Heating and Welding.1. Which of the following is an advantage of heating by electricity?(a) Quicker operation (b) Higher efficiency (c) Absence of flue gases (d) All of the aboveAns: d2. ________ has the highest value of thermal conductivity.(a) Copper (b) Aluminum (c) Brass (d) SteelAns: a3. Which of the following heating methods has maximum power factor?(a) Arc heating (b) Dielectric heating (c) Induction heating (d) Resistance heatingAns: d4. Method has leading power factor(a) Resistance heating (b) Dielectric heating (c) Arc heating (d) Induction heatingAns: b5. Is used for heating non-conducting materials.(a) Eddy current heating (b) Arc heating(c) Induction heating (d) Dielectric heatingAns: d6. Which of the following methods of heating is not dependent on the frequency of supply?(a) Induction heating (b) Dielectric heating(c) Electric resistance heating FOLLOWERS (d) All of the aboveAns: c7. When a body reflects entire radiation incident on it, then it is known as(a) White body (b) Grey body (c) Black body (d) Transparent bodyAns: a8. for the transmission of heat from one body to another(a) Temperature of the two bodies must be different(b) Both bodies must be solids (c) Both bodies must be in contact(d) At least one of the bodies must have some source of heatingAns: a9. Heat transfer by condition will not occur when(a) Bodies are kept in vacuum (b) Bodies are immersed in water(c) Bodies are exposed to thermal radiations(d) Temperatures of the two bodies are identicalAns: d10. A perfect black body is one that(a) Transmits all incident radiations (b) Absorbs all incident radiations(c) Reflects all incident radiations(d) Absorbs, reflects and transmits all incident radiationsAns: b

11. Heat is transferred simultaneously by condition, convection and radiation(a) Inside boiler furnaces(b) During melting of ice(c) Through the surface of the insulted pipe carrying steam(d) From refrigerator coils to freezer of a refrigeratorAns: a12. The process of heat transfer during the reentry of satellites and missiles, at very high Speeds, into earth's atmosphere is known as(a) Ablation (b) Radiation (c) Viscous dissipation (d) IrradiationAns: a13. Which of the following has the highest value of thermal conductivity?(a) Water (b) Steam (c) Solid ice (d) Melting iceAns: c14. Induction heating process is based on which of the following principles?(a) Thermal ion release principle (b) Nucleate heating principle(c) Resistance heating principle (d) Electro-magnetic induction principleAns: d15. Which of the following insulating materials was suitable for low temperature applications?(a) Asbestos paper (b) Diatomaceous earth (c) 80 percent magnesia (d) CorkAns: b16. A non-dimensional number generally associated with natural convection heat transfer is(a) Prandtl number (b) Grashoff number (c) Pecelet number (d) Nusselt numberAns: b17. The temperature inside a furnace is usually measured by which of the following?(a) Optical pyrometer (b) Mercury thermometer(c) Alcohol thermometer (d) Any of the aboveAns: a18. Which of the following will happen if the thickness of refractory wall of furnace is increased?(a) Heat loss through furnace wall will increase(b) Temperature inside the furnace will fall(c) Temperature on the outer surface of furnace walls will drop(d) Energy consumption will increaseAns: c19. The material of the heating element for a furnace should have(a) Lower melting point (b) Higher temperature coefficient(c) High specific resistance (d) all of the aboveAns: c

20. In a resistance furnace the atmosphere is(a) Oxidizing (b) Deoxidizing c) Reducing (d) neutralAns: a21. By which of the following methods the temperature inside arc nace can be varied?(a) By disconnecting some of the heating elements(b) By varying the operating voltage(c) By varying the current through heating elements (d) By any of the above methodAns: d22. In induction heating ______ is abnormally high.(a) Phase angle (b) Frequency (c) current (d) VoltageAns: b23. by the use of which of the following, high frequency power supply for induction furnaces Can be obtained?(a) Coreless transformers (b) Current transformers(c) Motor-generator set (d) Multi-phase transformerAns: c24. Induction furnaces are employed for which of the following?(a) Heat treatment of castings (b) Heating of insulators(c) Melting aluminum (d) none of the aboveAns: a25. In an electric room heat convector the method of heating used is(a) Arc heating (b) Resistance heating (c) Induction heating (d) Dielectric heatingAns: b26. In a domestic cake baking oven the temperature is controlled by(a) Voltage variation (b) Thermostat(c) auto-transformer (d) series-parallel operationAns: d27. In an electric press mica is used(a) As an insulator (b) As a device for power factor improvement(c) For dielectric heating (d) for induction heatingAns: a28. Induction heating takes place it which of the following?(a) Insulating materials (b) Conducting materials which are magnetic(c) Conducting materials which are non-magnetic(d) Conducting materials which may or may not be magneticAns: d29. For heating element high resistivity material is chosen to(a) Reduce the length of heating element (b) Increase the life of the heating element(c) Reduce the effect of oxidation (d) Produce large amount of heatAns: a

30. In resistance heating highest working temperature is obtained from heating elements made of(a) Nickel copper (b) nichrome (c) Silicon carbide (d) SilverAns: c31. for intermittent work which of the following furnaces is suitable?(a) Indirect arc furnace (b) Core less furnace(c) Either of the above (d) None of the aboveAns: a32. Due to which of the following reasons it is desirable to have short arc length?(a) To achieve better heating (b) To increase the life of roof refractory(c) To have better stirring action (d) To reduce problem of oxidation(e) All of the aboveAns: e33. In the indirect resistance heating method, maximum heat-transfer takes place by(a) Radiation (b) convection (c) conduction (d) any of the aboveAns: a34. Properly of low temperature co-eflficient of heating element is desired due to which of the following reasons?(a) To avoid initial rush of current (b) To avoid change in kW rating with temperature(c) Both (a) and (b) (d) Either (a) or (b)Ans: c35. Which of the following methods is used to control temperature in resistance furnaces?(a) Variation of resistance (b) Variation of voltage(c) Periodical switching on and off of the supply (d) All of the above methodsAns: d36. It is desirable to operate the arc furnaces at power factor of(a) Zero (b) 0.707 lagging (c) unity (d) 0.707 leadingAns: b37. Radiations from a black body are proportional to(a) T1 (b) T2 (c) T3 (d) T*Ans: d38. In arc furnace the function of choke is(a) To stabilize the arc (b) To improve, power factor(c) To reduce severity of the surge (d) None of the aboveAns: a39. Ajax Wyatt furnace is started when(a) it is filled below core level (b) it is filled above core level(c) it is fully empty (d) none of the aboveAns: b

40. In electric press, mica is used because it is _______ conductor of heat but/and________ conductor of electricity.(a) bad, good (b) bad, bad (c) good, bad (d) good, goodAns:41. Resistance variation method of temperature control is done by connecting resistance elements in(a) Series (b) parallel (c) series-parallel connections(d) star-delta connections (e) All of the above waysAns: e42. Hysteresis loss and eddy current loss are used in(a) Induction heating of steel (b) Dielectric heating(c) Induction heating of brass (d) Resistance heatingAns: a43. In heating the ferromagnetic material by induction heating, heat is produced due to(a) Induced current flow through the charge(b) Hysteresis loss taking place below curie temperature(c) due to hysteresis loss as well as eddy current loss taking place in the charge(d) None of the above factorsAns: c44. Radiant heating is used for which of the following?(a) Annealing of metals (b) Melting of ferrous metals(c) Heating of liquids in electric kettle (d) Drying of paints and varnishesAns: d45. Which of the following devices is necessarily required for automatic temperature control in a furnace?(a) Thermostat (b) Thermocouple(c) Auto-transformer (d) Heating elements of variable resis-tance materialAns: b46. For radiant heating around 2250°C, the heating elements are made of(a) Copper alloy (b) Carbon (c) Tungsten alloy (d) Stainless steel alloyAns: c47. The electrode of a direct arc furnace is made of(a) Tungsten (b) Graphite (c) Silver (d) CopperAns: b48. Direct arc furnaces have which of the following power factors?(a) Unity (b) Low, lagging (c) Low, leading (d) Any of the aboveAns: b49. In direct arc furnace, which of the following has high value?(a) Current (b) Voltage (c) Power factor (d) All of the aboveAns: a

50. Which of the following is an advantage of eddy current heating?(a) The amount of heat generated can be controlled accurately(b) The area of the surface over which heat is produced can be accurately controlled(c) Heat at very high rate can be gene-rated (d) All of the aboveAns: dIndustrial Drives .1. The selection of an electric motor for any application depends on which of the following factors ?(a) Electrical characteristics(b) Mechanical characteristics(c) Size and rating of motors(d) Cost(e) All of the aboveAns: e2. For a particular application the type of electric-and control gear are determined by which of the following considerations?(a) Starting torque(b) Conditions of environment(c) Limitation on starting current(d) Speed control range and its nature(e) All of the aboveAns: e3. Which of the following motors is preferred for traction work ?(a) Universal motor(b) D.C. series motor(c) Synchronous motor(d) Three-phase induction motorAns: b4. Which of the following motors always starts on load ?(a) Conveyor motor(b) Floor mill motor(c) Fan motor(d) All of the aboveAns: d5. is preferred for automatic drives.(a) Squirrel cage induction motor(b) Synchronous motors(c) Ward-Leonard controlled D.C. motors(d) Any of the aboveAns: c

6. When the load is above _____ a synchronous motor is found to be more economical.(a) 2 kW (b) 20 kW (c) 50 kW (d) 100 kWAns: d7. The load cycle for a motor driving a power press will be(a) Variable load (b) Continuous(c) Continuous but periodical (d) Intermittent and variable loadAns: d8. Light duty cranes are used in which of the following?(a) Power houses (b) Pumping stations(c) Automobile workshops (d) All of the aboveAns: d9. While selecting an electric motor for a floor mill, which electrical characteristics will be of least significance?(a) Running characteristics (b) Starting characteristics(c) Efficiency (d) BrakingAns: d10. Which of the following motors are pre-ferred for overhead travelling cranes?(a) Slow speed motors (b) Continuous duty motors(c) Short time rated motors (d) None of the aboveAns: c11. is preferred for synthetic fibre mills.(a) Synchronous motor (b) Reluctance motor(c) Series motor (d) Shunt motorAns: b12. Ward-Leonard controlled D.C. drives are generally used for ______ excavators.(a) Light duty (b) Medium duty (c) Heavy duty (d) All of the aboveAns: c13. Which of the following motors is used for elevators?(a) Induction motor (b) Synchronous motor(c) Capacitor start single phase motor (d) Any of the aboveAns: a14. Which part of a motor needs maximum attention for maintenance?(a) Frame (b) Rearing(c) Stator winding (d) Rotor windingAns: b15. Need frequent starting and stopping of electric motors,(a) Paper mills (b) Grinding mills(c) Air-conditioners (d) Lifts and hoistsAns: d

16. Which feature, while selecting a.motor for centrifugal pump, will be of least significance?(a) Starting characteristics(b) Operating speed(c) Horse power(d) Speed controlAns: d17. _______ motor is a constant speed motor.(a) Synchronous motor(b) Schrage motor(c) Induction motor(d) Universal motorAns: a18. The starting torque in case of centrifugal pumps is generally(a) Less than running torque(b) Same as running torque(c) Slightly more than running torque(d) Double the running torqueAns: a19. Which of the following motors are best for the rolling mills ?(a) Single phase motors(b) Squirrel cage induction motors(c) Slip ring induction motors(d) D.C. motorsAns: d20. is not a part of ball bearing ?(a) Inner race (b) Outer race (c) Cage (d) BushAns: d21. The starting torque of a D.C. motor is independent of which of the following?(a) Flux (b) Armature current(c) Flux and armature current (d) SpeedAns: d22. Rotor of a motor is usually supported on _______ bearings.(a) ball or roller (b) needle (c) bush (d) thrustAns: a23. For which of the following applications D.C. motors are still preferred?(a) High efficiency operation(b) Reversibility(c) Variable speed drive(d) High starting torqueAns: c

24. In a paper mill where constant speed is required(a) synchronous motors are preferred(b) A.C. motors are preferred(c) individual drive is preferred(d) group drive is preferredAns: c25. A reluctance motor(a) is provided with slip rings (b) requires starting gear(c) has high cost (d) is compactAns: d26. The size of an excavator is usually expressed in terms of(a) 'crowd' motion (b) angle of swing(c) cubic metres (d) travel in metresAns: c27. For blowers which of the following motor is preferred?(a) D.C. series motor (b) D.C. shunt motor(c) Squirrel cage induction motor (d) Wound rotor induction motorAns: b28. Belted slip ring induction motor is almost invariably used for(a) water pumps (b) jaw crushers(c) centrifugal blowers (d) none of the aboveAns: b29. Which of the following is essentially needed while selecting a motor?(a) Pulley (b) Starter (c) Foundation pedal (d) BearingsAns: b30. Reluctance motor is a(a) variable torque motor (b) low torque variable speed motor(c) self starting type synchronous motor (d) low noise, slow speed motorAns: c31 method of starting a three phase induction motor needs six terminals.(a) Star-delta (b) Resistance starting(c) Auto-transformer (d) none of the aboveAns: a32. In ______ method of staging three phase induction motors the starting voltage is not reduced.(a) auto-transformer (b) star-delta (c) slip ring (d) any of the aboveAns: c33. In jaw crushers a motor has to often start against ______ load.(a) Heavy (b) medium (c) normal (d) lowAns: a

34. For a motor-generator set which of the following motors will be preferred?(a) Synchronous motor(b) Slip ring induction motor(c) Pole changing induction motor(d) Squirrel cage induction motorAns: a35. Which of the following motors is usually preferred for kiln drives ?(a) Cascade controlled A.C. motor(b) Slip ring induction motor(c) Three phase shunt wound com-mutator motor(d) Any of the aboveAns: d36. Heat control switches are used in(a) Transformers (b) Cooling ranges(c) Three phase induction motors (d) Single phaseAns: b37 has relatively wider range of speed control.(a) Synchronous motor(6) Ship ring induction motor(c) Squirrel cage induction motor(d) D.C. shunt motorAns: d38. in squirrel cage induction motors which of the following methods of starting cannot be used?(a) Resistance in rotor circuit(b) Resistance in stator circuit(c) Auto-transformer starting(d) Star-delta startingAns: a39. In which of the following applications the load on motor changes in cyclic order ?(a) Electric shovels(b) Cranes (c) Rolling mills (d) All of the aboveAns: d40. Flame proof motors are used in(a) Paper mills (b) Steel mills(c) Moist atmospheres (d) Explosive atmospheresAns: d41. Which of the following machines has heavy fluctuation of load?(a) Printing machine (b) Punching machine (c) Planer (d) LatheAns: b

42. For derries and winches which of the following drives can be used?(a) Pole changing squirrel cage motors(b) D.C. motors with Ward-leonard con-trol(c) A.C. slip ring motors with variable resistance(d) Any of the aboveAns: d43. Battery operated scooter for braking uses(a) Plugging (b) Mechanical braking(c) Regenerative braking (d) rheostatic brakingAns: b44 has least range of speed control.(a) Slip ring induction motor (b) Synchronous motor(c) D.C. shunt motor (d) Schrage motorAns: b45. has the least value of starting torque to full load torque ratio.(a) D.C. shunt motor(b) D.C. series motor(c) Squirrel cage induction motor(d) Slip ring induction motorAns: c46. In case of _______ speed control by injecting e.m.f. in the rotor circuit is possible,(a) d.c. shunt motor (b) schrage motor(c) synchronous motor (d) slip ring induction motorAns: d47. A pony motor is used for the starting which of the following motors ?(a) Squirel cage induction motor (b) Schrage motor(c) Synchronous motor (d) None of the aboveAns: c48. In ________ the speed can be varied by changing the position of brushes.(a) slip ring motor (b) schrage motor(c) induction motor (d) repulsion motorAns: b49. In which of the following applications variable speed operation is preferred?(a) Exhaust fan (b) Ceiling fan (c) Refrigerator (d) Water pumpAns: b

50. Heavy duty cranes are used in(a) ore handling plants(b) steel plants(c) heavy engineering workshops(d) all of the aboveAns: d51. The travelling speed of cranes varies from(a) 20 to 30 m/s (b) 10 to 15 m/s (c) 5 to 10 m/s (d) 1 to 2.5 m/sAns: d52. Besides a constant speed a synchronous rotor possesses which of the followingadvantages?(a) Lower cost (b) Better efficiency(c) High power factor (d) All of the aboveAns: c53. By the use of which of the following D.C. can be obtained from AC.?(a) Silicon diodes (b) Mercury arc rectifier(c) Motor generator set (d) any of the aboveAns: d54. Which of the following motors is preferred when quick speed reversal is the mainconsideration?(a) Squirrel cage induction motor(b) Wound rotor induction motor(e) Synchronous motor (d) D.C. motorAns: d55. Which of the following motors is preferred when smooth and precise speed control over a wide range is desired?(a) D.C. motor(b) Squirrel cage induction motor(c) Wound rotor induction motor(d) Synchronous motorAns: a56. For crane travel which of the following motors is normally used?(a) Synchronous motor(b) D.C. differentially compound motor(c) Ward-Leonard controlled D.C. shunt motor(d) AC. slip ring motorAns: d57. The capacity of a crane is expressed in terms of(a) type of drive(b) span (c) tones (d) any of the aboveAns: c

58. The characteristics of drive for crane hoisting and lowering are which of the following ?(a) Precise control(b) Smooth movement(c) Fast speed control(d) All of the aboveAns: d59. Which of the following motors is preferred for boom hoist of a travelling crane ?(a) Single phase motor(b) Synchronous motor(c) A.C. slip ring motor(d) Ward-Leonard controlled D.C. shunt motorAns: c60. A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is(a) slop speed operation(b) high starting torque(c) low windage losses(d) all of the aboveAns: b61. Which of the following motors has series characteristics ?(a) Shaded pole motor(b) Repulsion motor(c) Capacitor start motor(d) None of the aboveAns: b62. Which of the following happens when star-delta starter is used ?(a) Starting voltage is reduced(b) Starting current is reduced(c) Both (a) and (b) (d) None of the aboveAns: c63. For a D.C. shunt motor which of the following is incorrect 7(a) Unsuitable for heavy duty starting(b) Torque varies as armature current(c) Torque-armature current is a straight line(d) Torque is zero for zero armature currentAns: a64. For which of the following applications motor has to start with high acceleration?(a) Oil expeller (b) Floor mill (c) Lifts and hoists (d) Centrifugal pumpAns: c

65. Which of the following types of motor enclosure is safest?(a) Totally enclosed(b) Totally enclosed fan cooled(c) Open type (d) Semi closedAns: b66. While selecting motor for an air conditioner which of the following characteristics is of great importance?(a) Type of bearings(b) Type of enclosure (c) Noise(d) Arrangement for power transmis¬sion(e) None of the aboveAns: c67. The diameter of the rotor shaft for an electric motor depends on which of the following ?(a) r.p.m. only (b) Horse power only(c) Horse power and r.p.m. (d) Horse power, r.p.m. and power factorAns: c68. Which of the following alternatives will be cheaper?(a) A 100 H.P. AC. three phase motor(b) Four motors of 25 H.P. each(c) Five motors of 20 H.P. each(d) Ten motors of 10 H.P. eachAns: a69. The cost of an induction motor will increase as(a) Horse power rating increases but r.p.m. decreases(b) Horse power rating decreases but r.p.m. increases(c) Horse power rating and operating speed increases(d) Horse power rating and operating speed decreasesAns: a70. In series motor which of the following methods can be used for changing the flux per pole?(a) Tapped field control(b) Diverter field control(c) Series-parallel control(d) Any of the aboveAns: d

Electric Traction 1. Which of the following is an advantage of electric traction over other methods of traction?(a) Faster acceleration(b) No pollution problems(c) Better braking action(d) All of the aboveAns: a2. Which of the following is the voltage for single phase A.C. system?(a) 22 V (b) 440 V (c) 5 kV (d) 15 kV (e) None of the aboveAns: a3. Long distance railways use which of the following?(a) 200 V D.C. (b) 25 kV single phase A.C. 10.(c) 25 kV two phase A.C. (d) 25 kV three phase A.C.Ans: b4. The speed of a locomotive is controlled by(a) flywheel(b) gear box(c) applying brakes 11.(d) regulating steam flow to engineAns: b5. Main traction systems used in India are, those using(a) electric locomotives(b) diesel engine locomotives(c) steam engine locomotives(d) diesel electric locomotives(e) all of the aboveAns: e6, in India diesel locomotives are manu¬factured at(a) Ajmer (b) Varanasi (c) Bangalore (d) JamalpurAns: b7. For diesel locomotives the range of horsepower is(a) 50 to 200(b) 500 to 1000(c) 1500 to 2500(d) 3000 to 5000Ans: c8. _______ locomotive has the highest operational availability.(a) Electric (b) Diesel (c) SteamAns: a

9. The horse power of steam locomotives is(a) up to 1500(b) 1500 to 2000(c) 2000 to 3000(d) 3000 to 4000Ans: a10. The overall efficiency of steam locomotive is around(a) 5 to 10 percent (b) 15 to 20 percent(c) 25 to 35 percent (d) 35 to 45 percentAns: a11. In tramways which of the following motors is used?(a) D.C. shunt motor (b) D.C. series motor(c) A.C. three phase motor (d) AC. single phase capacitor start motorAns: b12. In a steam locomotive electric power is provided through(a) Overhead wire (b) battery system(c) Small turbo-generator (d) diesel engine generatorAns: c13. Which of the following drives is suitable for mines where explosive gas exists?(a) Steam engine (b) Diesel engine(c) Battery locomotive (d) any of the aboveAns: c14. In case of locomotives the tractive power is provided by(a) Single cylinder double acting steam engine(b) Double cylinder, single acting steam engine(c) Double cylinder, double acting steam engine(d) Single stage steam turbineAns: c15. Overload capacity of diesel engines is usually restricted to(a) 2 percent (b) 10 percent (c) 20 percent (d) 40 percentAns: a16. In case of steam engines the steam pressure is(a) 1 to 4 kgf/cm2 (b) 5 to 8 kgf/cm2 (c) 10 to 15 kgf/cm2 (d) 25 to 35 kgf/cm2Ans: c17. The steam engine provided on steam locomotives is(a) Single acting condensing type (b) Single acting non-condensing type(e) Double acting condensing type (d) Double acting non-condensing typeAns: b

18. Electric locomotives in India are manufactured at(a) Jamalpur (b) Bangalore(c) Chittranjan (d) GorakhpurAns: c19. The wheels of a train, engine as well as bogies, are slightly tapered to(a) reduce frietion(b) increase friction(c) facilitate braking(d) facilitate in taking turnsAns: d20. Automatic signalling is used for which of the following trains ?(a) Mail and express trains(b) Superfast trains(c) Suburban and Urban electric trains(d) All trainsAns: b21. The efficiency of diesel locomotives is nearly(a) 20 to 25 percent (b) 30 to 40 percent(c) 45 to 55 percent (d) 60 to 70 percentAns: a22. The speed of a superfast train is(a) 60 kmph(b) 75 kmph(c) 100 kmph(d) more than 100 kmphAns: d23. The number of passanger coaches that can be attached to a diesel engine locomotive on broad gauge is usually restricted to(a) 5 (b) 10 (c) 14 (d) 17Ans: b24. Which of the following state capitals is not on broad gauge track ?(a) Lucknow (b) Bhopal(c) Jaipur (d) ChandigarhAns: c25. Which of the following is the advantage of electric braking ?(a) It avoids wear of track(b) Motor continues to remain loaded during braking(c) It is instantaneous(d) More heat is generated during brakingAns: a

24. Which of the following braking systems on the locomotives is costly ?(a) Regenerative braking on electric locomotives(b) Vacuum braking on diesel locomo-tives(c) Vacuum braking on steam locomo-tives(d) All braking systems are equally costlyAns: a27. Tractive effort is required to(a) overcome the gravity component of train mass(b) overcome friction, windage and curve resistance(c) accelerate the train mass(d) do all of the aboveAns: d28. For given maximum axle load tractive efforts of AC. locomotive will be(a) less than that of D.C. locomotive(b) more than that of D.C. locomotive(c) equal to that of D.C. locomotive(d) none of the aboveAns: b29. Co-efficient of adhesion reduces due to the presence of which of the following?(a) Sand on rails (b) Dew on rails (c) Oil on the rails (d) both (b) and (c)Ans: d30. Due to which of the following co-efficient of adhesion improves ?(a) Rust on the rails(b) Dust on the rails(c) Sand on the rails(d) All of the aboveAns: d31. Quadrilateral speed-time curve pertains to which of the following services ?(a) Main line service(b) Urban service(c) Sub-urban service(d) Urban and sub-urban serviceAns: d32. Which of the following is the disadvantage of electric traction over other systems of traction?(a) Corrosion problems in the under-ground pipe work(b) Short time power failure interrupts traffic for hours(c) High capital outlay in fixed instal-lations beside route limitation(d) Interference with communication lines (e) All of the aboveAns: c

33. Co-efficient of adhesion is(a) high in case of D.C. traction than in the case of AC. traction(b) low in case of D.C. traction than in the case of AC. traction(c) equal in both AC. and D.C. traction(d) any of the aboveAns: b34. Speed-time curve of main line service differs from those of urban and suburbanservices on following account(a) it has longer free running period(b) it has longer coasting period(c) accelerating and braking periods are comparatively smaller(d) all of the aboveAns: d35. The rate of acceleration on suburban orurban services is restricted by the consideration of(a) Engine power (b) Track curves (c) Passenger Discomfort (d) Track sizeAns: c36. The specific energy consumption of a train depends on which of the following?(a) Acceleration and retardation(b) Gradient(c) Distance covered(d) All of the aboveAns: d37. The friction at the track is proportional to(a) 1/speed (b) l/(speed)2(c) speed (d) none of the aboveAns: c38. The air resistance to the movement of the train is proportional to(a) speed (b) (speed) (c) (speed) (d) 1/speedAns: b39. The normal value of adhesion friction is(a) 0.12 (b) 0.25 (c) 0.40 (d) 0.75Ans: b40. The pulsating torque exerted by steam locomotives causes which of the following?(a) Jolting and skidding(b) Hammer blow(c) Pitching(d) All of the aboveAns: a

41. Which of the following braking systems is used on steam locomotives?(a) Hydraulic system (b) Pneumatic system(c) Vacuum system (d) none of the aboveAns: c42. Vacuum is created by which of the following?(a) Vacuum pump (b) Ejector (c) Any of the above (d) None of the aboveAns: c43. The resistance encountered by a trainin motion is on account of(a) Resistance offered by air (b) Friction at the track(c) Friction at various parts of the rolling stock (d) all of the aboveAns: d44. Battery operated trucks are used in(a) steel mills (b) power stations(c) narrow gauge traction (d) factories for material transportationAns: d45. Method can bring the locomotive to dead stop.(a) Plugging braking (b) Rheostatic braking(c) Regenerative braking (d) None of the aboveAns: a46. The value of co-efficient of adhesion will be high when rails are(a) Greased (b) wet (c) sprayed with oil (d) cleaned with sandAns: d47. The voltage used for suburban trains in D.C. system is usually(a) 12 V (b) 24 V (c) 220 V (d) 600 to 750 VAns: d48. for three-phase induction motors which of the following is the least efficient method of speed control?(a) Cascade control (b) Pole changing(c) Rheostatic control (d) Combination of cascade and pole changingAns: c49. Specific energy consumption becomes(a) More on steeper gradient (b) more with high train resistance(c) Less if distance between stops is more (d) all of the aboveAns: d50. In main line service as compared to urban and suburban service(a) Distance between the stops is more (b) Maximum speed reached is high(c) Acceleration and retardation rates are low (d) all of the aboveAns: d

51. Locomotive having monomotor bogies(a) Has better coefficient of adhesion(b) Are suited both for passanger as well as freight service(c) has better riding qualities due to the reduction of lateral forces(d) has all above qualitiesAns: d52. Series motor is not suited for traction duty due to which of the following account ?(a) Less current drain on the heavy load torque(b) Current surges after temporary switching off supply(c) Self relieving property(d) Commutating property at heavy loadAns: b53. When a bogie negotiates a curve, reduction in adhesion occurs resulting insliding. Thus sliding is acute when(a) wheel base of axles is more (b) degree of curvature is more(c) both (a) and (b) (d) none of the aboveAns: c54. Energy consumption in propelling the train is required for which of the following?(a) Work against the resistance to motion(b) Work against gravity while moving up the gradient(c) Acceleration (d) All of the aboveAns: d55. An ideal traction system should have(a) easy speed control(b) high starting tractive effort(c) equipment capable of with standing large temporary loads(d) all of the aboveAns: d56. have maximum unbalanced forces(a) Diesel shunters(b) Steam locomotives(c) Electric locomotives(d) Diesel locomotivesAns: b57. Specific energy consumption is affected by which of the following factors ?(a) Retardation and acceleration values(b) Gradient(c) Distance between stops(d) All of the aboveAns: d

58. In case of ________ free running and coasting periods are generally long.(a) main-line service (b) urban service(c) sub-urban service (d) all of the aboveAns: a59. Overhead lines for power supply to tramcars are at a minimum height of(a) 3 m (b) 6 m (c) 10 m (d) 2 mAns: c60. The return circuit for tramcars is through(a) Neutral wire (b) rails (c) cables (d) common earthingAns: b61. Specific energy consumption is least in _______ service.(a) main line (b) urban (c) suburbanAns: a62. Locomotives with monometer bogies have(a) uneven distribution of tractive effect(b) suitability for passanger as well as freight service(c) lot of skidding (d) low co-efficient of adhesionAns: b63 _______ was the first city in India to adopt electric traction.(a) Delhi (b) Madras (c) Calcutta (d) BombayAns: d64 _______ frequency is not common in low frequency traction system(a) 40 Hz (b) 25 Hz (c) 16 HzAns: a65. For 25 kV single phase system power supply frequency is(a) 60 Hz (b) 50 Hz (c) 25 Hz (d) 16 HzAns: b66. Power for lighting in passanger coach, in a long distance electric train, is provided(a) directly through overhead electric line(b) through individual generator of bogie and batteries(c) through rails (d) through locomotiveAns: b67. In India, electrification of railway track was done for the first time in which of thefollowing years ?(a) 1820—1825 (b) 1880—1885 (c) 1925—1932 (d) 1947—1954Ans: c68. Suri transmission is(a) electrical-pneumatic (b) mechanical-electrical (c) hydro-mechanical (d) hydro-pneumaticAns: c

69. In case of a steam engine an average coal consumption per km is nearly(a) 150 to 175 kg (b) 100 to 120 kg (c) 60 to 80 kg (d) 28 to 30 kgAns: d70. Which of the following happens in Kando system ?(a) Three phase A.C. is converted into D.C.(b) Single phase A.C. is converted into D.C.(c) Single phase supply is converted into three phase system(d) None of the aboveAns: c71. For which of the following locomotives the maintenance requirements are the least?(a) Steam locomotives (b) Diesel locomotives(c) Electric locomotives (d) Equal in all of the aboveAns: b72. Which of the following methods is used to control speed of 25 kV, 50 Hz single phase traction?(a) Reduced current method(b) Tap changing control of transformer(c) Series parallel operation of motors(d) All of the aboveAns: b73. If the co-efficient of adhesion on dry rails is 0.26, which of the following could be the value for wet rails?(a) 0.3 (b) 0.26 (c) 0.225 (d) 0.16Ans: d74 watt-hours per tonne km is usually the specific energy consumption for suburbanservices.(a) 15—20 (b) 50—75 (c) 120—150 (d) 160—200Ans: b75. The braking retardation is usually in the range(a) 0.15 to 0.30 km phps (b) 0.30 to 0.6 km phps(c) 0.6 to 2.4 km phps (d) 3 to 5 km phps (e) 10 to 15 km phpsAns: d76. The rate of acceleration on suburban orurban service is in the range(a) 0.2 to 0.5 km phps (b) 1.6 to 4.0 km phps(c) 5 to 10 km phps (d) 15 to 25 km phpsAns: b77. The coasting retardation is around(a) 0.16 km phps (b) 1.6 km phps (c) 16 km phps (d) 40 km phpsAns: a

Control Systems 1. In an open loop control system(a) Output is independent of control input(b) Output is dependent on control input(c) Only system parameters have effect on the control output(d) None of the aboveAns: a2. For open control system which of the following statements is incorrect?(a) Less expensive(b) Recalibration is not required for maintaining the required quality of the output(c) Construction is simple and maintenance easy(d) Errors are caused by disturbancesAns: b3. A control system in which the control action is somehow dependent on the output is known as(a) Closed loop system(b) Semiclosed loop system(c) Open system(d) None of the aboveAns: a4. In closed loop control system, with positive value of feedback gain the overall gain of the system will(a) decrease(b) increase(c) be unaffected(d) any of the aboveAns: a5. Which of the following is an open loop control system ?(a) Field controlled D.C. motor(b) Ward leonard control(c) Metadyne(d) StroboscopeAns: a6. Which of the following statements is not necessarily correct for open control system ?(a) Input command is the sole factor responsible for providing the control action(b) Presence of non-linearities causes malfunctioning(c) Less expensive(d) Generally free from problems of non-linearitiesAns: b

7. In open loop system(a) the control action depends on the size of the system(b) the control action depends on system variables(c) the control action depends on the input signal(d) the control action is independent of the outputAns: d8. has tendency to oscillate.(a) Open loop system(b) Closed loop system(c) Both (a) and (b)(d) Neither (a) nor (b)Ans: b9. A good control system has all the following features except(a) good stability (b) slow response(c) good accuracy (d) sufficient power handling capacityAns: b10. A car is rtyining at a constant speed of 50 km/h, which of the following is the feedback element for the driver ?(a) Clutch (b) Eyes (c) Needle of the speedometer(d) Steering wheel (e) None of the aboveAns: c11. The initial response when tne output is not equal to input is called(a) Transient response(b) Error response(c) Dynamic response(d) Either of the aboveAns: a12. A control system working under unknown random actions is called(a) computer control system(b) digital data system(c) stochastic control system(d) adaptive control systemAns: c13. An automatic toaster is a ______ loop control system.(a) open (b) closed(c) partially closed (d) any of the aboveAns: a14. Any externally introduced signal affecting the controlled output is called a(a) Feedback (b) stimulus (c) signal (d) gain controlAns: b

15. A closed loop system is distinguished from open loop system by which of the following?(a) Servomechanism (b) Feedback(c) Output pattern (d) Input patternAns: b16 is a part of the human temperature control system.(a) Digestive system(b) Perspiration system(c) Ear (d) Leg movementAns: b17. By which of the following the control action is determined when a man walks along a path?(a) Brain (b) Hands (c) Legs (d) EyesAns: d18. Is a closed loop system.(a) Auto-pilot for an aircraft(6) Direct current generator(c) Car starter(d) Electric switchAns: a19. Which of the following devices are commonly used as error detectors in instruments?(a) Vernistats (b) Microsyns (c) Resolvers (d) Any of the aboveAns: d20. Which of the following should be done to make an unstable system stable?(a) The gain of the system should be decreased(b) The gain of the system should be increased(c) The number of poles to the loop transfer function should be increased(d) The number of zeros to the loop transfer function should be increasedAns: b21. Increases the steady state accuracy.(a) Integrator (b) Differentiator (c) Phase lead compensator (d) Phase lag compensatorAns: a22. A.C. servomotor resembles(a) two phase induction motor(b) Three phase induction motor(c) direct current series motor(d) universal motorAns: a

23. As a result of introduction of negative feedback which of the following will not decrease?(a) Band width (b) Overall gain (c) Distortion (d) InstabilityAns: a24. Regenerative feedback implies feedback with(a) oscillations (b) step input (c) negative sign (d) positive signAns: d25. The output of a feedback control system must be a function of(a) reference and output (b) reference and input(e) input and feedback signal (d) output and feedback signalAns: a26. is an open loop control system.(a) Ward Leonard control (b) Field controlled D.C. motor(c) Stroboscope (d) MetadyneAns: b27. A control system with excessive noise, is likely to suffer from(a) saturation in amplifying stages (b) loss of gain(c) vibrations (d) oscillationsAns: a28. Zero initial condition for a system means(a) input reference signal is zero(b) zero stored energy(c) ne initial movement of moving parts(d) system is at rest and no energy is stored in any of its componentsAns: d29. Transfer function of a system is used to calculate which of the following ?(a) The order of the system(b) The time constant(c) The output for any given input(d) The steady state gainAns: c30. The band width, in a feedback amplifier.(a) remains unaffected(b) decreases by the same amount as the gain increase(c) increases by the sane saaaajajt as the gain decrease(d) decreases by the same amount as the gain decreaseAns: c31. On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend ?(a) Frequency (b) Loop gain (c) Forward gain (d) All of the aboveAns: d

32. The transient response, with feedback system,(a) rises slowly (b) rises quickly (c) decays slowly (d) decays quicklyAns: d33. The second derivative input signals modify which of the following?(a) The time constant of the system(b) Damping of the system(c) The gain of the system(d) The time constant and suppress the oscillations(e) None of the aboveAns: d34. Which of the following statements is correct for any closed loop system ?(a) All the co-efficients can have zero value(6) All the co-efficients are always non-zero(c) Only one of the static error co-efficients has a finite non-zero value(d) None of the aboveAns: c35. Which of the following statements is correct for a system with gain margin close to unity or a phase margin close to zero ?(a) The system is relatively stable(b) The system is highly stable(c) The system is highly oscillatory(d) None of the aboveAns: c36. Due to which of the following reasons excessive bond width in control systems should be avoided ?(a) It leads to slow speed of response(b) It leads to low relative stability(c) Noise is proportional to band width(d) None of the aboveAns: c37. In a stable control system backlash can cause which of the following ?(a) Underdamping(b) Overdamping(c) Poor stability at reduced values of open loop gain(d) Low-level oscillationsAns: d38. In an automatic control system which of the following elements is not used ?(a) Error detector (b) Final control element(c) Sensor (d) OscillatorAns: d

39. In a control system the output of the controller is given to(a) Final control element (b) amplifier(c) Comparator (d) sensor(e) None of the aboveAns: a40. A controller, essentially, is a(a) Sensor (b) clipper (c) Comparator (d) AmplifierAns: c41. Which of the following is the input to a controller?(a) Servo signal (b) Desired variable value(c) Error signal (d) Sensed signalAns:42. The on-off controller is a _____ system.(a) digital (b) linear (c) non-linear (d) discontinuousAns:43. The capacitance, in force-current analogy, is analogous to(a) momentum (b) velocity (c) displacement (d) massAns: d44. The temperature, under thermal and electrical system analogy, is considered analogous to(a) Voltage (b) Current (c) Capacitance (d) Charge (e) none of the aboveAns: a45. In electrical-pneumatic system analogy the current is considered analogous to(a) velocity (b) pressure (c) air flow (d) air flow rateAns: d46. In liquid level and electrical system analogy, voltage is considered analogous to(a) Head (b) Liquid flow (c) Liquid flow rate (d) None of the aboveAns: a47. The viscous friction co-efficient, in force-voltage analogy, is analogous to(a) Charge (b) Resistance (c) Reciprocal of inductance(d) Reciprocal of conductance (e) none of the aboveAns: b48. In force-voltage analogy, velocity is analogous to(a) Current (b) charge (c) inductance (d) capacitanceAns: a49. In thermal-electrical analogy charge is considered analogous to(a) Heat flow (b) Reciprocal of heat flow(c) Reciprocal of temperature (d) Temperature(e) None of the aboveAns: d

50. Mass, in force-voltage analogy, is analogous to(a) Charge (b) Current (c) Inductance (d) ResistanceAns: c51. The transient response of a system is mainly due to(a) Inertia forces (b) Internal forces (c) Stored energy (d) FrictionAns: c52 signals will become zero when the feedback signal and reference signs are equal.(a) Input (b) Actuating (c) Feedback (d) ReferenceAns: b 53. A signal other than the reference input that tends to affect the value of controlledvariable is known as(a) Disturbance (b) command (c) control element (d) Reference inputAns: a54. The transfer function is applicable to which of the following?(a) Linear and time-in variant systems(b) Linear and time-variant systems(c) Linear systems(d) Non-linear systems(e) None of the aboveAns: a55. From which of the following transfer function can be obtained ?(a) Signal flow graph(b) Analogous table(c) Output-input ratio(d) Standard block system(e) None of the aboveAns: a56 is the reference input minus the primary feedback.(a) Manipulated variable (b) Zero sequence(c) Actuating signal (d) Primary feedbackAns: c57. The term backlash is associated with(a) Servomotors (b) Induction relays(c) Gear trains (d) Any of the aboveAns:58. with feedback _____ increases.(a) System stability(b) Sensitivity(c) gain (d) effects of disturbing signalsAns: a

59. By which of the following the system response can be tested better ?(a) Ramp input signal(b) Sinusoidal input signal(c) Unit impulse input signal(d) Exponentially decaying signalAns: c60. In a system zero initial condition means that(a) The system is at rest and no energy is stored in any of its components(b) The system is working with zero stored energy(c) The system is working with zero reference signalAns: a61. In a system low friction co-efficient facilitates(a) reduced velocity lag error(b) increased velocity lag error(c) increased speed of response(d) reduced time constant of the systemAns: a62. Hydraulic torque transmission system is analog of(a) amplidyne set(b) resistance-capacitance parallel circuit(c) motor-generator set(d) any of the aboveAns:63. Spring constant in force-voltage analogy is analogous to(a) capacitance(b) reciprocal of capacitance(c) current (d) resistanceAns: b64. The frequency and time domain are related through which of the following?(a) Laplace Transform and Fourier Integral(b) Laplace Transform(c) Fourier Integral(d) Either (b) or (c)Ans: a65. An increase in gain, in most systems, leads to(a) smaller damping ratio(b) larger damping ratio(c) constant damping ratio(d) none of the aboveAns: a

66. Static error co-efficients are used as a measure of the effectiveness of closed loopsystems for specified ________ input signal.(a) Acceleration (b) Velocity(c) Position (d) all of the aboveAns: d67. A conditionally stable system exhibits poor stability at(a) Low frequencies (b) Reduced values of open loop gain(c) Increased values of open loop gain (d) none of the aboveAns: b68. The type 0 system has ______ at the origin.(a) No pole (b) Net pole (c) Simple pole (d) Two poles(e) None of the aboveAns: a69. The type 1 system has ______ at the origin.(a) No pole bb (b) Net pole b (c) Simple pole (d) Two polesAns: c70. The type 2 system has at the origin.(a) No net pole (b) Net pole (c) Simple pole (d) two polesAns: d71. The position and velocity errors of a type-2 system are(a) Constant, constant (b) Constant, infinity (c) Zero, constant (d) Zero, zeroAns: c72. Velocity error constant of a system is measured when the input to the system is unit _______ function.(a) Parabolic (b) Ramp (c) Impulse (d) StepAns: b73. In case of type-1 system steady state acceleration is(a) Unity (b) Infinity (c) Zero (d) 10Ans: b74. If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is(a) not necessarily stable(b) stable (c) unstable (d) always unstable (e) any of the aboveAns: a75. Which of the following is the best method for determining the stability and transient response?(a) Root locus (b) Bode plot(c) Nyquist plot (d) none of the aboveAns: a

76. Phase margin of a system is used to specify which of the following?(a) Frequency response (b) Absolute stability(c) Relative stability (d) Time responseAns: c77. Addition of zeros in transfer function causes which of the following?(a) Lead-compensation(b) Lag-compensation(c) Lead-lag compensation(d) None of the aboveAns: b78. technique is not applicable to nonlinear system ?(a) Nyquist Criterion(b) Quasi linearization(c) Functional analysis(d) Phase-plane representationAns: a79. In order to increase the damping of a badly underdamped system which of following compensators may be used ?(a) Phase-lead(b) Phase-lag(c) Both (a) and (b)(d) Either (a) and (b)(e) None of the aboveAns: a80. The phase lag produced by transportation relays(a) is independent of frequency(b) is inverseh'proportional to frequency(c) increases linearly with frequency(d) decreases linearly with frequencyAns: c81. In a stable control system saturation can cause which of the following?(a) Low-level oscillations(b) High-level oscillations(c) Conditional stability (d) over dampingAns: a82. Which of the following can be measured by the use of a tacho-generator ?(a) Acceleration (b) Speed(c) Speed and acceleration (d) Displacement(e) None of the aboveAns: b

83 is not a final control element.(a) Control valve (b) Potentiometer(c) Electro-pneumatic converter (d) ServomotorAns: b84. Which of the following is the definition of proportional band of a controller?(a) The range of air output as measured variable varies from maximum to minimum(b) The range of measured variables from set value(c) The range of measured variables through which the air output chan¬ges from maximum to minimum(d) Any of the above (e) None of the aboveAns: c85. In pneumatic control systems the control valve used as final control element converts(a) pressure signal to electric signal(b) pressure signal to position change(c) electric signal to pressure signal(d) position change to pressure signal(e) none of the aboveAns: b86. Pressure error can be measured by which of the following ?(a) Differential bellows and straingauge (b) Selsyn(c) Strain gauge (d) Strain gauge and potentiometerAns: a87. Which of the following devices is used for conversion of co-ordinates?(a) Microsyn (b) Selsyn (c) Synchro-resolver (d) Synchro-transformerAns: c88. The effect of error damping is to(a) provide larger settling lime (b) delay the response(c) reduce steady state error (d) any of the above(e) none of the aboveAns: c89 technique gives quick transient and stability response(a) Root locus (b) Bode (c) Nyquist (d) NicholsAns: a90. A phase lag lead network introduces in the output(a) lag at all frequencies(b) lag at high frequencies and lead at low frequencies(c) lag at low frequencies and lead at high frequencies(d) none of the aboveAns: c

91. Which of the following is the non-linearity caused by servomotor?(a) Static friction (b) Backlash(c) Saturation (d) None of the aboveAns: c92 can be extended to systems which are time-varying?(a) Bode-Nyquist stability methods (b) Transfer functions(c) Root locus design (d) State model representativesAns: d93. When the initial conditions of a system are specified to be zero it implies that the system is(a) At rest without any energy stored in it (b) Working normally with reference input(c) Working normally with zero reference input (d) At rest but stores energyAns: d94. Which of the following is an electromechanical device?(a) Induction relay (b) Thermocouple (c) LVDT(d) Any of the above (e) None of the aboveAns: c95. A differentiator is usually not a part of a control system because it(a) reduces damping (b) reduces the gain margin(c) increases input noise (d) increases errorAns: c96. If the gain of the critical damped system is increased it will behave as(a) Oscillatory (b) Critically damped (c) Over damped (d) under damped (e) None of the aboveAns: d97. In a control system integral error compensation _______ steady state error(a) increases (b) minimizes (c) does not have any effect on (d) any of the aboveAns: b98. With feed back _____ reduces.(a) system stability (b) system gain (c) system stability and gain (d) none of the aboveAns: b99. An amplidyne can give which of the following characteristics?(a) Constant current (b) Constant voltage (c) Constant current as well as constant voltage(d) Constant current, constant voltage and constant power(e) None of the aboveAns: d

100. Which of the following can be measured by LVDT?(a) Displacement (b) Velocity (c) Acceleration (d) Any of the aboveAns: d101 directly convert temperature into voltage.(a) Thermocouple (b) Potentiometer (c) Gear train (d) LVDT(e) None of the aboveAns: a102. The transfer function technique is considered as inadequate under which of thefollowing conditions? (a) Systems having complexities and non-linearities(b) Systems having stability problems(c) Systems having multiple input dis¬turbances(d) All of the aboveAns: d103. Which of the following is the output of a thermocouple?(a) Alternating current (b) Direct current (c) A.C. voltage (d) D.C. voltage (e) None of the aboveAns: d104. A.C. servomotor is basically a(a) Universal motor (b) single phase induction motor(c) Two phase induction motor (d) Three phase induction motorAns: c105. The first order control system, which is well designed, has a(a) small bandwidth(b) negative time constant(c) large negative transfer function pole(d) none of the aboveAns: c106. Which of the following is exhibited by Root locus diagrams?(a) The poles of the transfer function for a set of parameter values(b) The bandwidth of the system(c) The response of a system to a step input(d) The frequency response of a system(e) None of the aboveAns: a

Measurement and Instrumentation 1. The use of _____ instruments is merely confined within laboratories as stand¬ardizing instruments.(a) absolute (b) indicating (c) recording (d) integrating (e) none of the aboveAns: a2. Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured?(a) Absolute instruments (b) Indicating instruments(c) Recording instruments (d) Integrating instrumentsAns: b3. _____ instruments are those which measure the total quantity of electricity delivered in a particular time.(a) Absolute (b) Indicating (c) Recording (d) IntegratingAns: d4. Which of the following are integrating instruments?(a) Ammeters (b) Voltmeters (c) Wattmeters(d) Ampere-hour and watt-hour metersAns: d5. Resistances can be measured with the help of(a) Wattmeters (b) voltmeters (c) ammeters(d) Ohmmeters and resistance bridges (e) all of the aboveAns: d6. According to application, instruments are classified as(a) Switch board (b) portable (c) both (a) and (b)(d) moving coil (e) moving iron (f) both (d) and (e)Ans: c7. Which of the following essential features is possessed by an indicating instrument?(a) Deflecting device (b) Controlling device (c) Damping device (d) All of the aboveAns: d8. A _____ device prevents the oscillation of the moving system and enables the latter to reach its final position quickly(a) Deflecting (b) controlling (c) Damping (d) any of the aboveAns: c9. The spring material used in a spring control device should have the following property.(a) Should be non-magnetic (b) Most be of low temperature co-efficient(c) Should have low specific resistance (d) should not be subjected to fatigue(e) All of the aboveAns: e

10. Which of the following properties damping oil must possess?(a) Must be a good insulator (b) Should be non-evaporating(c) Should not have corrosive action upon the metal of the vane(d) The viscosity of the oil should not change with the temperature(e) All of the aboveAns: e11. A moving-coil permanent-magnet instrument can be used as _____ by using a low resistance shunt.(a) ammeter (b) voltmeter (c) flux-meter (d) ballistic galvanometerAns: a12. A moving-coil permanent-magnet instrument can be used as flux-meter(a) by using a low resistance shunt(b) by using a high series resistance(c) by eliminating the control springs(d) by making control springs of large moment of inertiaAns: c13. Which of the following devices may be used for extending the range of instruments ?(a) Shunts (b) Multipliers (c) Current transformers(d) Potential transformers (e) All of the aboveAns: e14. An induction meter can handle current upto(a) 10 A (b) 30 A (c) 60 A (d) 100 AAns: d15. For handling greater currents induction wattmeters are used in conjunction with(a) potential transformers(b) current transformers (c) power transformers(d) either of the above (e) none of the aboveAns: b16. Induction type single phase energy meters measure electric energy in(a) kW (b) Wh (c) kWh (d) VAR (e) None of the aboveAns: c17. Most common form of A.C. meters met with in every day domestic and industrialinstallations are(a) mercury motor meters (b) commutator motor meters(c) induction type single phase energy meters (d) all of the aboveAns: c18. Which of the following meters are not used on D.C. circuits(a) Mercury motor meters (b) Commutator motor meters(c) Induction meters (d) None of the aboveAns: c

19. Which of the following is an essential part of a motor meter ?(a) An operating torque system(b) A braking device(c) Revolution registering device(d) All of the aboveAns: d20. A potentiometer may be used for(a) measurement of resistance (b) measurement of current(c) calibration of ammeter (d) calibration of voltmeter (e) all of the aboveAns: e21 is an instrument which measures the insulation resistance of an electric circuit relative to earth and one another,(a) Tangent galvanometer (b) Meggar(c) Current transformer (d) none of the aboveAns: b22. The household energy meter is(a) an indicating instrument (b) a recording instrument(c) an integrating instrument (d) none of the aboveAns: c23. The pointer of an indicating instrument should be(a) Very light (b) very heavy (c) either (a) or (b) (d) neither (a) nor (b)Ans: a24. The chemical effect of current is used in(a) D.C. ammeter hour meter (b) D.C. ammeter(c) D.C. energy meter (d) none of the aboveAns: a25. In majority of instruments damping is provided by(a) Fluid friction (b) spring (c) eddy currents (d) all of the aboveAns: c26. An ammeter is a(a) Secondary instrument (b) Absolute instrument(c) Recording instrument (d) Integrating instrumentAns: a27. In a portable instrument, the controlling torque is provided by(a) Spring (b) gravity (c) eddy currents (d) all of the aboveAns: a28. The disc of an instrument using eddy current damping should be of(a) Conducting and magnetic material (b) Non-conducting and magnetic material(c) Conducting and non-magnetic material (d) none of the aboveAns: c

29. The switch board instruments(a) Should be mounted in vertical position (b) Should be mounted in horizontal position(c) Either (a) or (b) (d) neither (a) nor (b)Ans: a30. The function of shunt in an ammeter is to(a) By pass the current (b) Increase the sensitivity of the ammeter(c) Increase the resistance of ammeter (d) None of the aboveAns: a31. The multiplier and the meter coil in a voltmeter are in(a) series(b) Parallel (c) series-parallel (d) none of the aboveAns: a32. A moving iron instrument can be used for(a) D.C. only (b) A.C. only (c) both D.C. and A.C.Ans: c33. The scale of a rectifier instrument is(a) linear (b) non-linear (c) either (a) or (b) (d) neither (a) nor (b)Ans: a34. For measuring current at high frequency we should use(a) moving iron instrument (b) electrostatic instrument(c) thermocouple instrument (d) none of the aboveAns: c35. The resistance in the circuit of the moving coil of a dynamometer wattmeter should be(a) almost zero (b) low (c) high (d) none of the aboveAns: c36. A dynamometer wattmeter can be used for(a) both D.C. and A.C. (b) D.C. only (c) A.C. only (d) any of the aboveAns: a37. An induction wattmeter can be used for(a) both D.C. and A.C. (6) D.C. only (c) A.C. only (d) any of the aboveAns: b38. The pressure coil of a wattmeter should be connected on the supply side of the current coil when(a) load impedance is high (b) load impedance is low(c) supply voltage is low (d) none of the aboveAns: a39. In a low power factor wattmeter the pressure coil is connected(a) to the supply side of the current coil (b) to the load side of the current coil(c) in any of the two meters at connection (d) none of the aboveAns: b

40. In a low power factor wattmeter the compensating coil is connected(a) in series with current coil (b) in parallel with current coil(c) in series with pressure coil (d) in parallel with pressure coilAns: c41. In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was(a) unity (6) 0.8 lagging (c) 0.8 leading (d) zeroAns: a42. In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be(a) unity (b) 0.5 (c) 0.3 (d) zeroAns: b43. The adjustment of position of shading bands, in an energy meter is done to provide(a) friction compensation (b) creep compensation(c) braking torque (d) none of the aboveAns: a44. An ohmmeter is a(a) moving iron instrument (b) moving coil instrument(c) dynamometer instrument (d) none of the aboveAns: b45. When a capacitor was connected to the terminal of ohmmeter, the pointer indicated a low resistance initially and then slowly came to infinity position. This shows that capacitor is(a) short-circuited (b) all right (c) faultyAns: b46. For measuring a very high resistance we should use(a) Kelvin's double bridge (b) Wheat stone bridge(c) Meggar (d) None of the aboveAns: c47. The electrical power to a meggar is provided by(a) battery (b) permanent magnet D.C. generator(c) AC. Generator (d) any of the aboveAns: b48. In a meggar controlling torque is provided by(a) spring (b) gravity (c) coil (d) eddy currentAns: c49. The operating voltage of a meggar is about(a) 6 V (b) 12 V (c) 40 V (d) 100 VAns: d

50. Murray loop test can be used for location of(a) ground fault on a cable (b) short circuit fault on a cable(c) both the ground fault and the short-circuit fault (d) none of the aboveAns: c51. Which of the following devices should be used for accurate measurement of low D.C. voltage ?(a) Small range moving coil voltmeter(b) D.C. potentiometer(c) Small range thermocouple voltmeter(d) None of the aboveAns: b52. It is required to measure the true open circuit e.m.f. of a battery. The best device is(a) D.C. voltmeter(b) Ammeter and a known resistance(c) D.C. potentiometer(d) None of the aboveAns: c53. A voltage of about 200 V can be measured(a) directly by a D.C. potentiometer(b) a D.C. potentiometer in conjunction with a volt ratio box(c) a D.C. potentiometer in conjunction with a known resistance(d) none of the aboveAns: b54. A direct current can be measured by(a) a D.C. potentiometer directly(b) a D.C. potentiometer in conjunction with a standard resistance(c) a D.C. potentiometer in conjunction with a volt ratio box(d) none of the aboveAns: b55. To measure a resistance with the help of a potentiometer it is(a) necessary to standardise the potentiometer(b) not necessary to standardise the potentiometer(c) necessary to use a volt ratio box in conjunction with the potentiometer(d) none of the aboveAns: b56. A phase shifting transformer is used in conjunction with(a) D.C. potentiometer (b) Drysdale potentiometer(c) A.C. co-ordinate potentiometer (d) Crompton potentiometerAns: b

57. Basically a potentiometer is a device for(a) comparing two voltages (b) measuring a current(c) comparing two currents (d) measuring a voltage (e) none of the aboveAns: a58. In order to achieve high accuracy, the slide wire of a potentiometer should be(a) as long as possible(b) as short as possible(c) neither too small not too large(d) very thickAns: a59. To measure an A. C. voltage by using an A.C. potentiometer, it is desirable that the supply for the potentiometer in taken(a) from a source which is not the same as the unknown voltage(b) from a battery(c) from the same source as the unknown voltage(d) any of the aboveAns: c60. The stator of phase shifting transformer for use in conjunction with an A.C.potentiometer usually has a(a) single-phase winding (b) two-phase winding(c) three-phase winding (d) any of the aboveAns: b61. In an AC. co-ordinate potentiometer, the currents in the phase and quadraturepotentiometer are adjusted to be(a) out of phase by 90° (b) out of phase by 60°(c) out of phase by 30° (d) out of phase by 0° (e) out of phase by 180°Ans: a62. A universal RLC bridge uses(a) Maxwell bridge configuration for measurement of inductance and De Santas bridge for measurement of capacitance(b) Maxwell Wein bridge for measurement of inductance and modified De Santy's bridge for measurement of capacitance(c) Maxwell Wein bridge for measurement of inductance and Wein bridge for measurement of capacitance(d) Any of the above.Ans: b63. For measurements on high voltage capacitors, the suitable bridge is(a) Wein bridge (b) Modified De Santy's bridge(c) Schering bridge (d) Any of the above(e) None of the aboveAns: c

64. In an Anderson bridge, the unknown inductance is measured in terms of(a) known inductance and resistance(b) known capacitance and resistance(c) known resistance(d) known inductanceAns: b65. Wagner earthing device is used to eliminate errors due to(a) electrostatic coupling(b) electromagnetic coupling(c) both (a) and (b)(d) none of the aboveAns: a66. For measurement of mutual inductance we can use(a) Anderson bridge(b) Maxwell's bridge(c) Heaviside bridge(d) Any of the aboveAns: c67. For measurement of inductance having high value, we should use(a) Maxwell's bridge(b) Maxwell Wein bridge(c) Hay's bridge(d) Any of the aboveAns: c68. If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is(a) 10° (b) 80° (c) 120° (d) 170°Ans: a69. In a Schering bridge the potential of the detector above earth potential is(a) a few volts only (b) 1 kV (c) 5 kV (d) 10 kVAns: a70. To avoid the effect of stray magnetic field in A.C. bridges we can use(a) Magnetic screening (b) Wagner earthing device(c) Wave filters (d) any of the aboveAns: a71. If an inductance is connected in one arm of bridge and resistances in the remaining three arms(a) the bridge can always be balanced (b) the bridge cannot be balanced(c) the bridge can be balanced if the resistances have some specific valuesAns: b

72. A power factor meter has(a) one current circuit and two pres¬sure circuits(b) one current circuit and one pressure circuit(c) two current circuits and one pres¬sure circuit(d) none of the aboveAns: a73. The two pressure coils of a single phase power factor meter have(a) the same dimensions and the same number of turns(b) the same dimension but different number of turns(c) the same number of turns but different dimensions(d) none of the aboveAns: a74. In a single phase power factor meter the phase difference between the currents in the two pressure coils is(a) exactly 0° (b) approximately 0° (c) exactly 90° (d) approximately 90°Ans: c75. In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at(a) 0° (b) 60° (c) 90° (d) 120°Ans: d76. In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of(a) 0.1 Hz (b) 0.25 Hz (c) 0.5 Hz (d) 1.5 HzAns: c77. In a Weston frequency meter, the magnetic axes of the two fixed coils are(a) parallel (b) perpendicular(c) inclined at 60° (d) inclined at 120°Ans: b78. A Weston frequency meter is(a) moving coil instrument (b) moving iron instrument(c) dynamometer instrument (d) none of the aboveAns: b79. A Weston synchronoscope is a(a) moving coil instrument (b) moving iron instrument(c) dynamometer instrument (d) none of the aboveAns: c80. In a Weston synchronoscope, the fixed coils are connected across(a) bus-bars (b) incoming alternator(c) a lamp (d) none of the aboveAns: b

81. In Weston synchronoscope the moving coil is connected across(a) bus-bars (b) incoming alternator(c) fixed coils (d) any of the aboveAns: a82. The power factor of a single phase load can be calculated if the instruments available are(a) one voltmeter and one ammeter(b) one voltmeter, one ammetqr and one wattmeter(c) one voltmeter, one ammeter and one energy meter(d) any of the aboveAns: b83. The desirable static characteristics of a measuring system are(a) accuracy and reproducibility (b) accuracy, sensitivity and reproducibility(c) drift and dead zone (d) static errorAns: b84. The ratio of maximum displacement deviation to full scale deviation of the instrument is called(a) static sensitivity (b) dynamic deviation(c) linearity (d) precision or accuracyAns: c85. Systematic errors are(a) instrumental errors (b) environmental errors(c) observational errors (d) all of the aboveAns: d86. Standard resistor is made from(a) Platinum (b) maganin (c) silver (d) nichromeAns: b87. Commonly used standard capacitor is(a) spherical type (b) concentric cylindrical type(c) electrostatic type (d) multilayer parallel plate typeAns: b88. Operating torques in analogue instruments are(a) Deflecting and control(b) Deflecting and damping(c) Deflecting, control and damping (d) vibration and balancingAns: c89. Commonly used instruments in power system measurement are(a) Induction (b) moving coil or iron(c) Rectifier (d) electrostaticAns: a

90. Damping of the Ballistic galvanometer is made small to(a) Get first deflection large(b) Make the system oscillatory(c) Make the system critically damped(d) Get minimum overshootAns: a91. If an instrument has cramped scale for larger values, then it follows(a) Square law (b) Logarithmic law(c) Uniform law (d) none of the aboveAns: b92. Volt box is a component to(a) extend voltage range (b) measure voltage(c) compare voltage in a box (d) none of the aboveAns: a93. E.m.f. of a Weston cell is accurately measured by(a) Electrostatic voltmeter(b) Hot wire voltmeter(c) Isothermal voltmeter(d) electrodynamic voltmeterAns: a94. The gravity controlled instrument has crowded scale because current is proportional to(a) balancing weight (b) deflection angle (c) sine of deflection angleAns: c95. A sensitive galvanometer produces large deflection for a(a) small value of current (b) large value of current(c) large value of power (d) large value of voitage(e) none of the aboveAns: a96. A multirangq instrument has(a) multiple shunt or series resistances inside the meter(b) multicoii arrangement(c) variable turns of coil(d) multi range meters inside the measurement system(e) any of the aboveAns: a97. The rectifier instrument is not free from(a) temperature error (b) wave shape error(c) frequency error (d) all of the aboveAns: c

98. Alternating current is measured by(a) induction ammeter(b) permanent magnet type ammeter(c) electrostatic ammeter(d) moving iron repulsion type voltmeterAns: a99. Most sensitive galvanometer is(a) elastic galvanometer(b) vibration galvanometer(c) Duddlb galvanometer(d) spot ballistic galvanometerAns: d100. Instrument transformers are(a) potential transformers(b) current transformers(c) both (a) and (b)(d) power transformersAns: c101. An instrument transformer is used to extend the range of(a) induction instrument (b) electrostatic instrument(c) moving coil instrument (d) any of the aboveAns: a102. Wattmeter cannot be designed on the principle of(a) electrostatic instrument(b) thermocouple instrument(c) moving iron instrument(d) electrodynamic instrumentAns: c103. In an energymeter braking torque is produced to(a) safe guard it against creep(b) brake the instrument(c) bring energy meter to stand still(d) maintain steady speed and equal to driving torqueAns: d104. Various adjustments in an energy meter include(a) light load or friction(b) lag and creep(c) overload and voltage compensation(d) temperature compensation(e) all of the aboveAns: e

105. The power of a n-phase circuit can be measured by using a minimum of(a) (n - 1) wattmeter elements(b) n wattmeter elements(c) (n + 1) wattmeter elements(d) 2n wattmeter elementsAns: a106. Two holes in the disc of energymeter are drilled at the opposite sides of the spindle to(a) improve its ventilation(b) eliminate creeping at no load(c) increase its deflecting torque(d) increase its braking tcrqueAns: b107. Which of the following is measured by using a vector voltmeter?(a) Amplifier gain and phase shift(b) Filler transfer functions(c) Complex insersion loss(d) All of the aboveAns: d108. The principle on which vector voltmeter is based is(a) that it works on the principle of complex variation(b) that it measures the response of linear ramp voltage(c) same as digital meter(d) that it measures the amplitude of a single at two points and at the same time measurestheir phase differenceAns: d109. To measure radio frequency, the suitable frequency meter is(a) Weston frequency meter(b) reed vibrator frequency meter(c) hetrodyne frequency meter(d) electrical resonance frequency meterAns: c

D.C. Generators 1. Laminations of core are generally made of(a) case iron(b) carbon(c) silicon steel(d) stainless steelAns: c2. Which of the following could be lamina-proximately the thickness of lamina-tionsof a D.C. machine ?(a) 0.005 mm(b) 0.05 mm(c) 0.5 m(d) 5 mAns: c3. The armature of D.C. generator is laminated to(a) reduce the bulk(b) provide the bulk(c) insulate the core(d) reduce eddy current lossAns: d4. The resistance of armature winding depends on(a) length of conductor(b) cross-sectional area of the conductor(c) number of conductors(d) all of the aboveAns: d5. The field coils of D.C. generator are usually made of(a) mica(b) copper(c) cast iron(d) carbonAns: b6. The commutator segments are connected to the armature conductors by meansFOLLOWERSof(a) copper lugs(b) resistance wires(c) insulation pads(d) brazingAns: a7. In a commutator

(a) copper is harder than mica(b) mica and copper are equally hard(c) mica is harder than copper(d) none of the aboveAns: c8. In D.C. generators the pole shoes are fastened to the pole core by(a) rivets(b) counter sunk screws(c) brazing(d) weldingAns: b9. According to Fleming's right-hand rule for finding the direction of induced e.m.f.,when middle finger points in the direction of induced e.m.f., forefinger will point inthe direction of(a) motion of conductor(b) lines of force(c) either of the above(d) none of the aboveAns: b10. Fleming's right-hand rule regarding direction of induced e.m.f., correlates(a) magnetic flux, direction of current flow and resultant force(b) magnetic flux, direction of motion and the direction of e.m.f. induced(c) magnetic field strength, induced voltage and current(d) magnetic flux, direction of force and direction of motion of conductorAns: b11. While applying Fleming's right-hand rule to And the direction of induced e.m.f.,the thumb points towards(a) direction of induced e.m.f.(b) direction of flux(c) direction of motion of the conductor if forefinger points in the direction of generated e.m.f.(d) direction of motion of conductor, if forefinger points along the lines of fluxAns: d12. The bearings used to support the rotor shafts are generally(a) ball bearings(b) bush bearings(c) magnetic bearmgs(d) needle bearingsAns: a13. In D.C. generators, the cause of rapid brush wear may be

(a) severe sparking(b) rough commutator surface(c) imperfect contact(d) any of the aboveAns: d14. In lap winding, the number of brushes is always(a) double the number of poles(b) same as the number of poles(c) half the number of poles(d) twoAns: b15. For a D.C. generator when the number of poles and the number of armatureconductors is fixed, then which winding will give the higher e.m.f. ?(a) Lap winding(b) Wave winding(c) Either of (a) and (b) above(d) Depends on other features of designAns: b16. In a four-pole D.C. machine(a) all the four poles are north poles(b) alternate poles are north and south(c) all the four poles are south poles(d) two north poles follow two south polesAns: b17. Copper brushes in D.C. machine are used(a) where low voltage and high currents are involved(b) where high voltage and small cur-rents are involved(c) in both of the above cases(d) in none of the above casesAns: a18. A separately excited generator as compared to a self-excited generator(a) is amenable to better voltage con-trol(b) is more stable(c) has exciting current independent of load current(d) has all above featuresAns: d19. In case of D.C. machines, mechanical losses are primary function of(a) current(b) voltage(c) speed

(d) none of aboveAns: c20. Iron losses in a D.C. machine are independent of variations in(a) speed(b) load(c) voltage(d) speed and voltageAns: b21. In D.C. generators, current to the external circuit from armature is given through(a) commutator(b) solid connection(c) slip rings(d) none of aboveAns: a23. Brushes of D.C. machines are made of(a) carbon(b) soft copper(c) hard copper(d) all of aboveAns: a24. If B is the flux density, I the length of conductor and v the velocity of conductor, theninduced e.m.f. is given by(a)Blv(b)Blv2(c)Bl2v(d)Bl2v2Ans: a25. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils,the pole pitch will be(a) 4(b) 8(c) 16(d) 32Ans: b26. The material for commutator brushes is generally(a) mica(b) copper(c) cast iron

(d) carbonAns: d27. The insulating material used between the commutator segments is normally(a) graphite(b) paper(c) mica(d) insulating varnishAns: c28. In D.C. generators, the brushes on commutator remain in contact with conductors which(a) lie under south pole(b) lie under north pole(c) lie under interpolar region(d) are farthest from the polesAns: c29. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be(a) demagnetisation only(b) cross magnetisation as well as magnetisation(c) crossmagnetisation as well as demagnetising(d) cross magnetisation onlyAns: c30. Armature reaction of an unsaturated D.C. machine is(a) crossmagnetising(b) demagnetising(c) magnetising(d) none of aboveAns: a31. D.C. generators are connected to the busbars or disconnected from them only under thefloating condition(a) to avoid sudden loading of the primemover(b) to avoid mechanicaljerk to the shaft(c) to avoid burning of switch contacts(d) all aboveAns: d32. Eddy currents are induced in the pole shoes of a D.C. machine due to(a) oscillating magnetic field(b) pulsating magnetic flux(c) relative rotation between field and armature

(d) all aboveAns: c33. In a D.C. machine, short-circuited field coil will result in(a) odour of barning insulation(b) unbalanced magnetic pull producing vibrations(c) reduction of generated voltage for which excitation has to be increased to maintain thevoltage(d) all aboveAns:34. Equilizer rings are required in case armature is(a) wave wound(b) lap wound(c) delta wound(d) duplex woundAns: b35. Welding generator will have(a) lap winding(b) wave winding(c) delta winding(d) duplex wave windingAns: a36. In case of D.C. machine winding, number of commutator segments is equal to(a) number of armature coils(b) number of armature coil sides(c) number of armature conductors(d) number of armature turnsAns: a37. For a D.C. machines laboratory following type of D.C. supply will be suitable(a) rotary converter(b) mercury are rectifier(c) induction motor D.C. generator set(d) synchronous motor D.C. generator setAns: c38. The function of pole shoes in the case of D.C. machine is(a) to reduce the reluctance of the magnetic path(b) to spread out the flux to achieve uniform flux density(c) to support the field coil(d) to discharge all the above functionsAns: d39. In the case of lap winding resultant pitch is

(a) multiplication of front and back pitches(b) division of front pitch by back pitch(c) sum of front and back pitches(d) difference of front and back pitchesAns: d40. A D.C. welding generator has(a) lap winding(b) wave moving(c) duplex winding(d) any of the aboveAns: a41. Which of the following statement about D.C. generators is false ?(a) Compensating winding in a D.C. machine helps in commutation(b) In a D. C. generator interpoles winding is connected in series with the armature winding(c) Back pitch and front pitch are both odd and approximately equal to the pole pitch(d) Equilizing bus bars are used with parallel running of D.C. shunt generatorsAns: d42. The demagnetising component of armature reaction in a D.C. generator(a) reduces generator e.m.f.(b) increases armature speed(c) reduces interpoles flux density(d) results in sparking troubleAns: a43. Magnetic field in a D.C. generator is produced by(a) electromagnets(b) permanent magnets(c) both (a) and (b)(d) none of the aboveAns: a44. The number of brushes in a commutator depends on(a) speed of armature(b) type of winding(c) voltage(d) amount of current to be collectedAns: d45. Compensating windings are used in D.C. generators(a) mainly to reduce the eddy currents by providing local short-circuits(b) to provide path for the circulation of cooling air(c) to neutralise the cross-magnetising effect of the armature reaction

(d) none of the aboveAns: c46. Which of the following components of a D.C, generator plays vital role for providing directcurrent of a D.C. generator ?(a) Dummy coils(b) Commutator(c) Eye bolt(d) Equilizer ringsAns: b47. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by(a) using conductor of annealed copper(b) using commutator with large number of segments(c) using carbon brushes of superior quality(d) using equiliser ringsAns: c48. In D.C. generators, lap winding is used for(a) high voltage, high current(b) low voltage, high current(c) high voltage, low current(d) low voltage, low currentAns: b49. Two generators A and B have 6-poles each. Generator A has wave wound armature whilegenerator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B willbe(a) 2 : 3(b) 3 : 1(c) 3 : 2(d) 1 : 3Ans: b50. The voltage drop for which of the following types of brush can be expected to be least ?(a) Graphite brushes(b) Carbon brushes(c) Metal graphite brushes(d) None of the aboveAns: c

51. The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be(a) E/2(b) 2E(c) slightly less than E(d) EAns: b52. In a D.C. generator the actual flux distribution depends upon(a) size of air gap(b) shape of the pole shoe(c) clearance between tips of the ad¬jacent pole shoes(d) all of the aboveAns:53. The armature core of a D.C. generator is usually made of(a) silicon steel(b) copper(c) non-ferrous material(d) cast-ironAns: a9.63. Satisfactory commutation of D.C. machines requires(a) brushes should be of proper grade and size(b) brushes should smoothly run in the holders(c) smooth, concentric commutator properly undercut(d) all of the aboveAns: d54. Open circuited armature coil of a D.C. machine is(a) identified by the scarring of the commutator segment to which open circuited coil isconnected(b) indicated by a spark completely around the commutator(c) both (a) and (b)(d) none of the aboveAns: c55. In a D.C. machine, fractional pitch winding is used(a) to increase the generated voltage(b) to reduce sparking(c) to save the copper because of shorter end connections(d) due to (b) and (c) aboveAns:

56. For the parallel operation of two or more D.C. compound generators, we should ensurethat(a) voltage of the incoming generator should be same as that of bus bar(b) polarity of incoming generator should be same as that of bus bar(c) all the series fields should be run in parallel by means of equilizer connection(d) series fields of all generators should be either on positive side or negative side of the armature(e) all conditions mentioned above should be satisfiedAns: d57. D.C. series generator is used(a) to supply traction load(b) to supply industrial load at constant voltage(c) voltage at the toad end of the feeder(d) for none of the above purposeAns: c58. Following D.C. generator will be in a position to build up without any residual magnetism inthe poles(a) series generator(b) shunt generator(c) compound generator(d) self-excited generatorAns: d59. Interpole flux should be sufficient to(a) neutralise the commutating self induced e.m.f.(b) neutralise the armature reaction flux(c) neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil(d) perform none of the above functionsAns: c60. D.C. generator generally preferred for charging automobile batteries is(a) series generator(b) shunt generator(c) long shunt compound generator(d) any of'the aboveAns: c61. In a D.C. generator the number of mechanical degrees and electrical degrees will be thesame when(a) r.p.m. is more than 300

(b) r.p.m. is less than 300(c) number of poles is 4(d) number of poles is 2Ans: d62. Permeance is the reciprocal of(a) flux density(b) reluctance(c) ampere-turns(d) resistanceAns: b63. In D.C. generators the polarity of the interpoles(a) is the same as that of the main pole ahead(b) is the same as that of the immediately preceding pole(c) is opposite to that of the main pole ahead(d) is neutral as these poles do not play part in generating e.m.f.Ans: a64. The e.m.f. generated in a D.C. generator is directly proportional to(a) flux/pole(b) speed of armature(c) number of poles(d) all of the aboveAns: b65. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis,when(a) there is no load on|he generator(b) the generator runs on full load(c) the generator runs on overload(d) the generator runs on designed speedAns: a66. In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in thecoil is neutralised by all of the following except(a) interpoles(b) dummy coils(c) compensating winding(d) shifting of axis of brushesAns: b67. In D.C. generators on no-load, the air gap flux distribution in space is(a) sinusoidal

(b) triangular(c) pulsating(d) flat toppedAns: d68. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speedincreases to 1200 r.p.m., the generated e.m.f. will be nearly(a) 150 V(b) 175 V(c) 240 V(d) 290 VAns: c69. The purpose of providing dummy coils in a generator is(a) to reduce eddy current losses(b) to enhance flux density(c) to amplify voltage(d) to provide mechanical balance for the rotorAns: d70. In a shunt generator the voltage build up is generally restricted by(a) speed limitation(b) armature heating(c) insulation restrictions(d) saturation of ironAns:71. If a D.C. generator fails to build up the probable cause could not be(a) imperfect brush contact(b) field resistance less than the critical resistance(c) no residual magnetism in the generator(d) faulty shunt connections tending to reduce the residual magnetismAns: b72. Flashing the field of D.C. generator means(a) neutralising residual magnetism(b) creating residual magnetism by a D.C. source(c) making the magnetic losses of forces parallel(d) increasing flux density by adding extra turns of windings on polesAns: b73. The e.m.f. induced in the armature of a shunt generator is 600 V. The armatureresistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be(a) 640 V(b) 620 V(c) 600 V

(d) 580 VAns: d74. In a D.C. generator the critical resistance refers to the resistance of(a) brushes(b) field(c) armature(d) loadAns: b75. To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so asto bring them(a) just ahead of magnetic neutral axis(b) in magnetic neutral axis(c) just behind the magnetic neutral axisAns: a76. Armature coil is short circuited by brushes when it lies(a) along neutral axis(b) along field axis(c) in any of the above positions(d) in none of the above positionsAns: a77. A cumulatively compounded long shunt generator when operating as a motor would be(a) cumulatively compounded long shunt(b) differentially compounded long shunt(c) cumulatively compounded short shunt(d) differentially compounded short shuntAns: b78. To avoid formation of grooves in the commutator of a D.C. machine(a) the brushes of opposite polarity should track each other(b) the brushes of same polarity should track each other(c) brush position has no effect on the commutator groovingAns: a79. The following constitute short-circuit in the armature winding.(a) Insulation failure between two com-mutator bars(6) Insulation failure between two turns of a coil(c) Two of more turns of the same coil getting grounded(d) All of the aboveAns: d80. The rapid wear of brushes takes place due to(a) abrasion from dust

(b) excessive spring pressure(c) rough commutator bars(d) high mica insulation between com-mutation bars(e) all of the above factorsAns: e81. Number of tappings for each equilizer ring is equal to(a) number of pole pairs(b) number of poles(c) number of parallel paths(d) number of commutator segmentsAns: a82. A D.C. generator can be considered as(a) rectifier(b) primemover(c) rotating amplifier(d) power pumpAns: c83. In any rotating machine that part which houses the conductors and in which e.m.f. inducedis to be utilised is called(a) rotor(b) stator(c) field(d) armatureAns: d84. In a D.C. machine stray loss is the sum of(a) total copper loss and mechanical loss(b) armature copper loss and iron loss(c) shunt field copper loss and mechanical loss(d) iron loss and mechanical lossAns: d85. Lap winding is composed of(a) any even number of conductors(b) any odd number of conductors(c) that even number which is exact multiple of poles + 2(d) that even number which is exact multiple of polesAns: a86. In a D.C. generator in case the resistance of the field winding is increased, then outputvoltage will(a) increase

(b) decrease(c) remain unaffected(d) fluctuate heavilyAns: b87. An exciter for a turbo generator is a(a) separately excited generator(b) shunt generator(c) series generator(d) compound generatorAns: b88. In case of a flat compounded generator(a) voltage generated is less than the rated voltage(b) generated voltage is proportional to the load on the generator(c) voltage remains constant irrespec¬tive of the load(d) speed varies in proportion to the load on the generatorAns: c89. Which of the following generator will have negligible terminal voltage while running on noload ?(a) Series generator(b) Shunt generator(c) Compound generator(d) Separately excited generatorAns: a90. Which of the following D.C. generators will be in a position to build up without any residualmagnetism in the poles ?(a) Series generator(b) Shunt generator(c) Compound generator(d) None of the aboveAns: d91. In over compounded generator, full load terminal voltage is(a) almost zero(b) less than noload terminal voltage(c) more than noload terminal voltage(d) equal to no-load terminal voltageAns: c92. In a level compounded D.C. generator, full load terminal voltage is(a) negligibly low(b) equal to no-load terminal voltage

(c) more than no-load terminal voltage(d) less than no-load terminal voltageAns: b93. The terminal voltage of a D.C. shunt generator drops on load because of all of thefollowing reasons except(a) armature reaction(b) armature resistance drop(c) field weakening due to armature reaction and armature(d) commutationAns: d94. In a D.C. generator(a) external resistance = internal char-acteristic - armature reaction(b) internal characteristic = magnetisation characteristic - ohmic drop(c) external characteristic = magnetisation characteristic - ohmic drop - armature reaction(d) magnetisation characteristic = external characteristicAns: c95. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armaturevoltage wave(a) will be zero(b) will be of 5 Hz(c) willbeof5xiVHz(d) will be of v Hz 5Ans: b96. A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltagewill be(a) zero(b) about 2 V(c) about 50 V(d) 220 VAns: b97. In a separately excited generator supplying rated load the armature reaction ,(a) is always present(b) is always absent(c) may be sometimes present(d) none of the aboveAns: a

98. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed willbe(a) zero(b) small(c) the same as rated voltage(d) highAns: a99. Armature reaction in a generator results in(a) demagnetisation of leading pole tip and magnetisation of trailing pole tip(b) demagnetisation of trailing pole tip and magnetisation of leading pole tip(c) damagnetising the centre of all poles(d) magnetising the centre of all polesAns: a100. Following energized winding of a D.C. machine should not be opened as it wouldproduce high inductive voltage which may be dangerous to personnel and may cause its owninsulation failure.(a) Series field(b) Compensating field(c) Inter pole field(d) Shunt fieldAns: d101. Wave winding is composed of(a) any even number of conductors(b) any odd number of conductors(c) that even number which is exact multiple of poles + 2(d) that even number which is exact multiple of polesAns: c102. The critical resistance of the D.C. generator is the resistance of(a) field(b) brushes(c) armature(d) loadAns: a103. When two D.C. series generators are running in parallel, an equilizer bar is used(a) to increase the speed and hence generated e.m.f.(b) to increase the series flux(c) so that two similar machines will pass approximately equal currents to the load(d) to reduce the combined effect of ar-mature reaction of both machines

Ans: c104. Which of the following generating machine will offer constant voltage on all loads ?(a) Self-excited generator(b) Separately excited generator(c) Level compounded generator .(d) All of the aboveAns: c105. Which of the following generators will be preferred if they are required to be run inparallel ?(a) Shunt generators(b) Series generators(c) Compound generators(d) None of the aboveAns: a106. Two generators are running in parallel. One of the generators may run as motor forwhich of the following reasons ?(a) The direction of that generator is reversed(b) The speed of that generator is increased(c) The field of that generator is weakened(d) That generator takes large share of loadsAns: d107. A D.C. generator works on the principle of(a) Lenz's law(b) Ohm's law(c) Faraday's law of electromagnetic induction(d) none of the aboveAns: c108. A series generator can self-excite(a) only if the load current is zero(b) only if the load current is not zero(c) irrespective of the value of load current(d) none of the aboveAns: b109. A shunt generator can self-excite(a) only if the resistance of the field circuit is less than critical value(b) only if the resistance of the field circuit is greater than critical value(c) irrespective of the value of the resis-tance in the field circuitAns: a

110. The terminal voltage of a series generator is 150 V when the load current is 5 A. If theload current is increased to 10 A, the terminal voltage will be(a) 150 V(b) less than 150 V(c) greater than 150 V(d) none of the aboveAns: c111. The open circuit voltage of a compound generator is 250 V. At full load the terminalvoltage(a) will be less than 250 V(b) will always be 250 V(c) may be greater or less than 250 V(d) none of the aboveAns: c112. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and fieldresistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the loadcircuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be(a) 270 V(b) 267.5 V(c) 265 V(d) 257.4 VAns: b113. The essential condition for parallel operation of two D.C. generators is that they have '(a) same kW rating(b) the same operation r.p.m.(c) the same drooping voltage charac-teristics(d) same percentage regulationAns: c114. When two D.C. generators are running in parallel an equilizer bar is used(a) to increase the series flux(b) to increase the generated e.m.f.(c) to reduce the combined effect of ar-mature reaction of both the machines(d) so that the two identical machines will pass approximately equal currents to the loadAns: d115. With a D.C. generator which of the following regulation is preferred ?

(a) 100% regulation(b) infinite regulation(c) 50% regulation(d) 1% regulationAns: d116. Which generator would you prefer for feeding long D.C. transmission lines ?(a) Series generator(b) Shunt generator(c) Over compound generator(d) Flat compound generatorAns: c117. In a D.C. generator the critical resistance can be increased by(a) increasing its field resistance(b) decreasing its field resistance(c) increasing its speed(d) decreasing its speedAns: c118. The number of armature parallel paths in a two-pole D.C. generator having duplex lapwinding is(a) 2(b) 4(c) 6(d) 8Ans: b119. For both lap and wave windings, there are as many commutator bars as the number of(a) slots(b) armature conductors(c) winding elements(d) polesAns: c120. The series field of a short-shunt D.C. generator is excited by(a) external current(b) armature current(c) shunt current(d) load currentAns: d121. As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C.generator is approximately

(a) 40 percent(b) 25 percent(c) 10 percent(d) 5 percentAns: d122. Shunt generators are most suited for stable parallel operation because of their(a) rising voltage characteristics(b) identical voltage characteristics(c) drooping voltage characteristics(d) linear voltage characteristicsAns: c123. The main factor which leads to unstable parallel operation of flat and over compoundedgenerators is(a) their rising voltage characteristics(b) unequal number of turns in their series field windings(c) unequal speed regulation of their primemovers(d) unequal series field resistancesAns: a124. If a self excited D.C. generator after being installed, fails to build up on its first trial run,the first thing to do is to(a) reverse the field connections(b) increase the field resistance(c) increase the speed of primemover(d) check armature insulation resis¬tanceAns: aD.C Motors 1. No-load speed of which of the following motor will be highest ?(a) Shunt motor(b) Series motor(c) Cumulative compound motor(d) Differentiate compound motorAns: b2. The direction of rotation of a D.C. series motor can be changed by(a) interchanging supply terminals(b) interchanging field terminals(c) either of (a) and (b) above(d) None of the aboveAns: b3. Which of the following application requires high starting torque ?

(a) Lathe machine(b) Centrifugal pump(c) Locomotive(d) Air blowerAns: c4. If a D.C. motor is to be selected for conveyors, which rriotor would be preferred ?(a) Series motor(b) Shunt motor(c) Differentially compound motor(d) Cumulative compound motorAns: a5. Which D.C. motor will be preferred for machine tools ?(a) Series motor(b) Shunt motor(c) Cumulative compound motor(d) Differential compound motorAns: b6. Differentially compound D.C. motors can find applications requiring(a) high starting torque(b) low starting torque(c) variable speed FOLLOWERS(d) frequent on-off cyclesAns: b7. Which D.C. motor is preferred for elevators ?(a) Shunt motor(b) Series motor(c) Differential compound motor(d) Cumulative compound motorAns: d8. According to Fleming's left-hand rule, when the forefinger points in the direction of thefield or flux, the middle finger will point in the direction of(a) current in the conductor aovtaat of conductor(c) resultant force on conductor(d) none of the aboveAns: a9. If the field of a D.C. shunt motor gets opened while motor is running(a) the speed of motor will be reduced %(b) the armature current will reduce(c) the motor will attain dangerously high speed 1(d) the motor will continue to nuvat constant speed

Ans: c10. Starters are used with D.C. motors because(a) these motors have high starting torque(b) these motors are not self-starting(c) back e.m.f. of these motors is zero initially(d) to restrict armature current as there is no back e.m.f. while startingAns: d11. In D.C. shunt motors as load is reduced(a) the speed will increase abruptly(b) the speed will increase in proportion to reduction in load(c) the speed will remain almost/constant(d) the speed will reduceAns: c12. A D.C. series motor is that which(a) has its field winding consisting of thick wire and less turns(b) has a poor torque(c) can be started easily without load(d) has almost constant speedAns: a13. For starting a D.C. motor a starter is required because(a) it limits the speed of the motor(b) it limits the starting current to a safe value(c) it starts the motor(d) none of the aboveAns: b14. The type of D.C. motor used for shears and punches is(a) shunt motor(b) series motor(c) differential compoutid D.C. motor(d) cumulative compound D.C. motorAns: d15. If a D.C. motor is connected across the A.C. supply it will(a) run at normal speed(b) not run(c) run at lower speed(d) burn due to heat produced in the field winding by .eddy currentsAns: d16. To get the speed of D.C, motor below the normal without wastage of electrical energy isused.

(a) Ward Leonard control(b) rheostatic control(c) any of the above method(d) none of the above methodAns: a17. When two D.C. series motors are connected in parallel, the resultant speed is(a) more than the normal speed(b) loss than the normal speed(c) normal speed(d) zeroAns: c18. The speed of a D.C. shunt motor more than its full-load speed can be obtained by(a) decreasing the field current(b) increasing the field current(c) decreasing the armature current(d) increasing the armature currentAns: a19. In a D.C. shunt motor, speed is(a) independent of armature current(b) directly proportional to the armature current(c) proportional to the square of the current(d) inversely proportional to the armature currentAns: a20. A direct on line starter is used: for starting motors(a) iip to 5 H.P.(b) up to 10 H.P.(c) up to 15 H.P.(d) up to 20 H.P.Ans: a21. What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?(a) The motor will stop(b) The motor will continue to run(c) The armature may burn(d) The motor will run noisyAns: c22. In case of D.C. shunt motors the speed is dependent on back e.m.f. only because(a) back e.m.f. is equal to armature drop(b) armature drop is negligible(c) flux is proportional to armature current(d) flux is practically constant in D:C. shunt motors

Ans: d23. In a D.C. shunt motor, under the conditions of maximum power, the current in thearmature will be(a) almost negligible(b) rated full-load current(c) less than full-load current(d) more than full-load currentAns: d24. These days D.C. motors are widely used in(a) pumping sets(b) air compressors(c) electric traction(d) machine shopsAns: c25. By looking at which part of the motor, it can be easily confirmed that a particular motor isD.C. motor?(a) Frame(b) Shaft(c) Commutator(d) StatorAns: c26. In which of the following applications D.C. series motor is invariably tried?(a) Starter for a car(b) Drive for a water pump(c) Fan motor(d) Motor operation in A.C. or D.C.Ans: a27. In D.C. machines fractional pitch winding is used(a) to improve cooling(b) to reduce copper losses(c) to increase the generated e.m.f.(d) to reduce the sparkingAns: d28. A three point starter is considered suitable for(a) shunt motors(b) shunt as well as compound motors(c) shunt, compound and series motors(d) all D.C. motorsAns: b

29. In case-the conditions for maximum power for a D.C. motor are established, theefficiency of the motor will be(a) 100%(b) around 90%(c) anywhere between 75% and 90%(d) less than 50%Ans: d30. The ratio of starting torque to full-load torque is least in case of(a) series motors(b) shunt motors(c) compound motors(d) none of the aboveAns: b32. In D.C. motor which of the following can sustain the maximum temperature rise?(a) Slip rings(b) Commutator(c) Field winding(d) Armature windingAns: c33. Which of the following law/rule can he used to determine the direction of rotation of D.C.motor ?(a) Lenz's law(b) Faraday's law(c) Coloumb's law(d) Fleming's left-hand ruleAns: d34. Which of the following load normally needs starting torque more than the rated torque?(a) Blowers(b) Conveyors(c) Air compressors(d) Centrifugal pumpsAns: b35. The starting resistance of a D.C. motor is generally(a) low(b) around 500 Q(c) 1000 Q(d) infinitely largeAns: a

36. The speed of a D.C. series motor is(a) proportional to the armature current(b) proportional to the square of the armature current(c) proportional to field current(d) inversely proportional to the armature currentAns: d37. In a D.C. series motor, if the armature current is reduced by 50%, the torque of themotor will be equalto(a) 100% of the previous value(b) 50% of the previous value(c) 25% of the previous value(d) 10% of the previous value(e) none of the aboveAns: c38. The current drawn by the armature of D.C. motor is directly proportional to(a) the torque required(b) the speed of the motor(c) the voltage across the terminals(d) none of the aboveAns: a39. The power mentioned on the name plate of an electric motor indicates(a) the power drawn in kW(b) the power drawn in kVA(c) the gross power(d) the output power available at the shaftAns: d40. Which D.C. motor has got maximum self loading property?(a) Series motor(b) Shunt motor(c) Cumulatively compounded 'motor(d) Differentially compounded motorAns: d41. Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavy loads?(a) Series motor(b) Shunt motor(c) Cumulatively compounded motor(d) Differentially compounded motorAns: c

42. If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens(a) nothing will happen to th£ motor(b) this will make armature to take heavy current, possibly burning it(c) this will result in excessive speed, possibly destroying armature due to excessivecentrifugal stresses (d) motor will run at very slow speedAns: c43. D.C. series motors are used(a) where load is constant(b) where load changes frequently(c) where constant operating speed is needed(d) in none of the above situations.Ans: d44. For the same H.P. rating and full load speed, following motor has poor starting torque(a) shunt(b) series(c) differentially compounded(d) cumulativelyc'ompoundedAns: c45. In case of conductively compensated D.C. series motors, the compensating winding isprovided(a) as separately wound unit(6) in parallel with armature winding(c) in series with armature winding(d) in parallel with field windingAns: c46. Sparking at the commutator of a D.C. motor may result in(a) damage to commutator segments(b) damage to commutator insulation(c) increased power consumption(d) all of the aboveAns: d47. Which of the following motor is preferred for operation in highly explosive atmosphere ?(a) Series motor(b) Shunt motor(c) Air motor(d) Battery operated motorAns: c

48. If the supply voltage for a D.C. motor is increased, which of the following will decrease ?(a) Starting torque(b) Operating speed(c) Full-load current(d) All of the aboveAns: c49. Which one of the following is not the function of pole shoes in a D.C. machine ?(a) To reduce eddy current loss(b) To support the field coils(c) To spread out flux for better unifor-mity(d) To reduce the reluctance of the mag-netic pathAns: a50. The mechanical power developed by a shunt motor will be maximum when the ratio ofback e.m.f. to applied voltage is(a) 4.0(b) 2.0(c) 1.0(d) 0.5Ans: d51. The condition for maximum power in case of D.C. motor is(a) back e.m.f. = 2 x supply voltage(b) back e.m.f. = | x supply voltage(c) supply voltage = | x back e.m.f.(d) supply voltage = back e.m.f.Ans: b52. For which of the following applications a D.C. motor is preferred over an A.C. motor ?(a) Low speed operation(b) High speed operation(c) Variable speed operation(d) Fixed speed operationAns: c53. In D.C. machines the residual magnetism is of the order of(a) 2 to 3 per cent(6) 10 to 15 per cent(c) 20 to 25 per cent(d) 50 to 75 per centAns: a

54. Which D.C. motor is generally preferred for cranes and hoists ?(a) Series motor(b) Shunt motor(c) Cumulatively compounded motor(d) Differentially compounded motorAns: a55. Three point starter can be used for(a) series motor only(b) shunt motor only(c) compound motor only(d) both shunt and compound motorAns: d56. Sparking, is discouraged in a D.C. motor because(a) it increases the input power con-sumption(b) commutator gets damaged(c) both (a) and (b)(d) none of the aboveAns: b57. Speed control by Ward Leonard method gives uniform speed variation(a) in one direction(b) in both directions(c) below normal speed only(d) above normal speed only.Ans: b58. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor,compound motor will haveto be(a) level compounded(b) under compounded(c) cumulatively compounded(d) differentially compoundedAns: c59. Following motor is used where high starting torque and wide speed range control isrequired.(a) Single phase capacitor start(b) Induction motor(c) Synchronous motor(d) D.C. motor(e) None of the above

Ans: d60. In a differentially compounded D.C. motor, if shunt field suddenly opens(a) the motor will first stop and then run in opposite direction as series motor(b) the motor will work as series motor and run at slow speed in the same direction(c) the motor will work as series motor and run at high speed in the same direction(d) the motor will not work and come to stopAns: a61. Which of the following motor has the poorest speed regulation ?(a) Shunt motor(b) Series motor(c) Differential compound motor(d) Cumulative compound motorAns: b62. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of(a) D.C. series motor(b) D.C. shunt motor(c) induction motor(d) all of above motorsAns: a63. As -the load is increased the speed of D.C. shunt motor will(a) reduce slightly(b) increase slightly(c) increase proportionately(d) remains unchangedAns: a64. The armature torque of the D.C. shunt motor is proportional to(a) field flux only(b) armature current only(c) both (a) and (b)(d) none of the aboveAns: b65. Which of the following method of speed control of D.C. machine will offer minimum efficiency ?(a) Voltage control method(b) Field control method(c) Armature control method(d) All above methodsAns: c66. Usually wide and sensitive speed control is desired in case of(a) centrifugal pumps

(b) elevators(c) steel rolling mills(d) colliery windersAns: d67. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. Thespeed regulation of the motor is(a) 2.36%(6) 4.76%(c) 6.77%(d) 8.84%Ans: b68. The armature voltage control of D.C. motor provides(a) constant torque drive(b) constant voltage drive(c) constant current drive(d) none of the aboveAns: a69. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent aheavy current from flowing though the armature circuit(a) a resistance is connected in series with armature(b) a resistance is connected parallel to the armature(c) armature is temporarily open circuited(d) a high value resistor is connected across the field windingAns: a70. The speed of a D.C. shunt motor can be increased by(a) increasing the resistance in armature circuit(b) increasing the resistance in field circuit(c) reducing the resistance in the field circuit(d) reducing the resistance in the armature circuitAns: b71. If I2 be the armature current, then speed of a D.C. shunt motor is(a) independent of Ia(b) proportional to la(c) varies as (Ia)(d) varies as laAns: a72. In case the back e.m.f. and the speed of a D.C. motor are doubled, the torquedeveloped by the motor will(a) remain unchanged

(6) reduce to one-fourth value(c) increase four folds(d) be doubledAns: a73. At the instant of starting when a D.C. motor is put on supply, it behaves like(a) a highly resistive circuit(6) a low resistance circuit(c) a capacitive circuit(d) none of the aboveAns: b74. The speed of a D.C. motor can be varied by varying(a) field current(b) applied voltage(c) resistance in series with armature(d) any of the aboveAns: d75. Which one of the following is not necessarily the advantage of D.C. motors over A.C.motors ?(a) Low cost(b) Wide speed range(c) Stability(d) High starting torque.Ans: a76. For a D.C. shunt motor if the excitation is changed(a) torque will remain constant(b) torque will change but power will remain constant(c) torque and power both will change(d) torque, power and speed, all will changeAns: b77. Which motor has the poorest speed control?(a) Differentially compounded motor(b) Cumulatively compounded motor(c) Shunt motor(d) Series motorAns: d78. The plugging gives the(a) zero torque braking(b) smallest torque braking(c) highest torque braking

(d) none of the aboveAns: c79. The armature voltage control of D.C. motor provides(a) constant voltage drive(b) constant current drive(c) constant torque drive(d) none of the aboveAns: c80. If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambienttemperature, then the motor(a) of lower H.P. should be selected(6) of higher H.P. should be selected(c) can be used for 50°C ambient temperature also(d) is to be derated by a factor recom-mended by manufacturer and select the next higherH.P. motorAns: d81. If the terminals of armature of D.C. motor are interchanged, this action will offer followingkind of braking(o) regenerative(b) plugging(c) dynamic braking(d) none of the above(e) any of the aboveAns: b82. Which of the following motors one will choose to drive the rotary compressor ?(a) D.C. shunt motor(b) D.C. series motor(c) Universal motor(d) Synchronous motorAns: d83. If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will(a) increase(b) decrease(c) remain same(d) become zeroAns: a84. Why are the D.C. motors preferred for traction applications ?(a) Torque and speed are inversely proportional to armature current

(b) Torque is proportional to armature current(c) Torque is proportional to square root of armature current(d) The speed is inversely proportional to the torque and the torque is proportional tosquare of armature currentAns: d85. Which of the following motors is usually used in house-hold refrigerators ?(a) D.C. shunt motor(b) D.C. series motor(c) Single phase induction motor (split phase start or induction run motor)(d) Reluctance motor(e) Synchronous motorAns: c86. Which of the following motors is most suitable for signalling devices and many kinds oftimers ?(a) D.C. shunt motor(b) D.C. series motor(c) Induction motor(d) Reluctance motorAns: d87. Which motor should not be started on no-load ?(a) Series motor(b) Shunt motor(c) Cumulatively compounded motor(d) Differentially compounded motor.Ans: a88. Ward-Leonard control is basically a(a) voltage control method(b) field divertor method(c) field control method(d) armature resistance control methodAns: a89. For constant torque drive which speed control method is preferred ?(a) Field control(b) Armature voltage control(c) Shunt armature control(d) Mechanical loading systemAns: b90. In Ward-Leonard control the lower limit of speed is imposed by(a) residual magnetism of the generator(b) core losses of motor

(c) mechanical losses of motor and gen¬erator together(d) all of the aboveAns: a91. The main disadvantage of the Ward-Leonard control method is(a) high initial cost(b) high maintenance cost(c) low efficiency at Hght loads(d) all of the aboveAns: d92. Regenerative method of braking is based on that(a) back e.m.f. is less than the applied voltage(b) back e.m.f. is equal to the applied voltage(c) back e.m.f. of rotor is more than the applied voltage(d) none of the aboveAns: b93. The hysteresis loss in a D.C. machine least depends on(a) Frequency of magnetic reversals(b) Maximum value of flux density(c) Volume and grade of iron(d) Rate of flow of ventilating airAns: d94. In a D.C. generator all of the following could be the effects of iron losses except(a) Loss of efficiency(b) Excessive heating of core(c) Increase in terminal voltage(d) Rise in temperature of ventilating airAns: c95. The losses occurring in a D.C. generator are given below. Which loss is likely to havehighest proportion at rated load of the generator ?(a) hysteresis loss(b) field copper loss(c) armature copper loss(d) eddy current lossAns: c96. Which of the following loss in a D.C. generator varies significantly with the load current ?(a) Field copper loss(b) Windage loss(c) Armature copper loss(d) None of the above

Ans: c97. Torque developed by a D.C. motor depends upon(a) magnetic field(b) active length of the conductor(c) current flow through the conductors(d) number of conductors(e) radius of armature(f) all above factorsAns: f98. D.C. shunt motors are used for driving(a) trains(b) cranes(c) hoists(d) machine toolsAns: d99. In a manual shunt motor starter(a) over load relay is connected in series and no volt relay in parallel with the load(6) over load relay is connected in paral¬lel and no volt relay in series with the load(c) over load relay and no volt relay are both connected in series with the load(d) over load relay and no volt relay are both connected in parallel with the loadAns: a100. Which of the following steps is likely to result in reduction of hysteresis loss in a D.C.generator ?(a) Providing laminations in armature core(b) Providing laminations in stator(c) Using non-magnetic material for frame(d) Using material of low hysteresis co-efficient for armature core materialAns: d101. Which of the following loss in a D.C. generator is dissipated in the form of heat?(a) Mechanical loss(b) Core loss(c) Copper loss(d) All of the aboveAns: d102. Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?(a) Hysteresis losses(b) Eddy current losses(c) Copper losses

(d) Windage lossesAns: b103. The total losses in a well designed D.C. generator of 10 kW will be nearly(a) 100 W(b) 500 W(c) 1000 W(d) 1500 WAns: b104. The condition for maximum efficiency for a D.C. generator is(a) eddy current losses = stray losses(b) hysteresis losses = eddy current losses(c) copper losses = 0(d) variable losses = constant lossesAns: d105. D.C. generators are normally designed for maximum efficiency around(a) full-load(b) rated r.p.m.(c) rated voltage(d) all of the aboveAns: a106. In a D.C. generator, the iron losses mainly take place in(a) yoke(b) commutator(c) armature conductors(d) armature rotorAns: d107. D.C. generators are installed near the load centres to reduce(a) iron losses(b) line losses(c) sparking(d) corona lossesAns: b108. The purpose of retardation test on D.C. shunt machines is to find out(a) stray losses(b) eddy current losses(c) field copper losses(d) windage lossesAns: a109. Which of the following tests will be suitable for testing two similar D.C. series motors of

large capacity ?(a) Swinburne's test(b) Hopkinson's test(c) Field test(d) Brake testAns: c110. Hopkinson's test on D.C. machines is conducted at(a) no-load(b) part load(c) full-load(d) overloadAns: c111. During rheostat braking of D.C. series motors(a) motor is run as a generator(b) motor is reversed in direction(c) motor is run at reduced speedAns: a112. For which types of D.C. motor, dynamic braking is generally used ?(a) Shunt motors(b) Series motors(c) Compound motors(d) All of the aboveAns: d113. Which method of braking is generally used in elevators ?(a) Plugging(b) Regenerative braking(c) Rheostatic braking(d) None of the aboveAns: a114. In variable speed motor(a) a stronger commutating field is needed at low speed than at high speed(b) a weaker commutating field is needed at low speed than at high speed(c) same commutating field is needed at low speed than at high speed(d) none of the above is correctAns: b115. When the armature of a D.C. motor rotates, e.m.f. induced is(a) self-induced e.m.f.(b) mutually induced e.m.f.(c) back e.m.f.(d) none of the aboveAns: c

116. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversingand speed control(a) drum type controller is used(b) three point starter is used(c) four point starter is used(d) all above can be usedAns: a117. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens(a) this will make armature to take heavy current, possibly burning it(6) this will result in excessive speed, possibly destroying armature due to excessivecentrifugal stresses(c) nothing will happen to motor(d) motor will come to stopAns: a118. D.C. motor is to drive a load which has certain minimum value for most of the time andsome peak value for shortduration. We will select the(a) series motor(b) shunt motor(c) compound motor(d) any of the aboveAns: a119. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle andpeak value for short duration. We will select this(a) series motor(b) shunt motor(c) compound motor(d) any of the aboveAns: c120. Which D.C. motor has got maximum self relieving property ?(a) Series motor(6) Shunt motor(c) Cumulatively compounded motor(d) Differentially compounded motorAns: a121. In the D.C. motor the iron losses occur in(a) the field

(b) the armature(c) the brushes(d) the commutatorAns: b122. The speed of a D.C. shunt motor is required to be more than full load speed. This ispossible by(a) reducing the field current(b) decreasing the armature current(c) increasing the armature current(d) increasing the excitation current(e) none of the above methodsAns: a123. One D.C. motor drives another D.C. motor. The second D.C. motor when excited anddriven(a) runs as a generator(b) does not run as a generator(c) also runs as a motor comes to stop after sometimeAns: a