dgca ame es paper oct-2013

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PAPER- III (ELECTRICAL SYSTEM)

DGCA AME EXAM-----OCT SESSION-2013

Compiled & edited by:

Mohd Ali & Meenu Kumari

Email: [email protected]

Mob: +91-8802482422 Date: 15/Mar2014

Note: This question paper does not form in anyway the actual part of the DGCA AME Exam and hence requires

careful and necessary consultation with the core books.

The questions were compiled soon after the particular exam session after collecting from several candidates who

appeared in the same and are nearly same in order. Though careful consideration & reference has been made

with the core books while answering the questions, you may still refer the books in case of doubt.

1. Which of the electrical circuit will dissipate more heat : (BLT Page 29 part 1)

a. Figure a b. Figure b c. Figure c d. Both (b) & (c)

2. Smoke detectors use: (Pallet-page166)

a. capacitor discharge tubes b. spot fire detectors c. continuous fire wire elements d. photo diodes 3. While running, a synchronous motor is compelled to run at synchronous speed because of:-

(B. L. Thareja Vol II page no 1532, Chapter 38; AC 65-9A, Page-457)

a. damper winding in its pole faces b. magnetic locking between stator and rotor poles c. Induced emf. in rotor field winding by stator flux d. compulsion due to Lenzs law 4. The speed of a D.C. motor can be controlled by varying: - B.L Thareja, Page 321 a. Its flux b. Armature circuit resistance c. Applied voltage d. All the above

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5. In a thermal switch employing steel and invar element actuation of the contacts under increasing temperature condition is caused by: Pallet-223, Chapter 6. a. expansion of the steel element only b. contraction of the invar element only c. expansion of the steel element causing displacement of the in rear element d. none of the above

6. The purpose of dump valve is: (Ref. General) a. to release cabin pressure to atmosphere on landing b. to ensure that differential cabin pressure is maintained throughout the flight c. to maintain cabin temperature as per the setting d. none of the above 7. Sulphation in a lead-acid battery occurs due to :- (B.L Thareja, Page-351)

a. Trickle charging b. Incomplete charging c. Heavy discharging d. Fast charging

8. The method used to rapidly charge a nickel cadmium battery utilizes :- (T.K. Eismin, Page-52)

a. constant current and constant voltage

b. constant current and varying voltage c. constant voltage and varying current d. none of these

9. The horn in landing gear warning circuit is activated by: (Ref. EHJ Pallet, 176 & 177)

a. up lock micro s/w b. down lock micro s/w c. engine throttle operated micro s/w d. all the above

10. The condition for LG system horn to come on is: (EHJ Pallett,P-177)

a. Any one LG is not DOWN & locked b. Any one LG is not UP & locked c. As in (a) and throttle at landing configuration d. As in (b) and throttle at take off configuration

11. Early effect in BJT refers to- BLT-IV page 2218

a. Avalanche break down

b. Thermal Breakdown

c. Base narrowing d. Zener break down 12. Mark the correct statement, Synchronous motor- BLT-2 Page 1

a. Not self stating b. At low speed high efficiency and p. f. > 1 c. Use for centrifugal pump d. All of the above

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13. Mark the correct statement regarding wire bundle : (15A, wire)

a. 3 or more wire going together to the same location b. 2 or more wire group going to same location c. 3 or more wire group going to same location 14. Mark the correct statement, Anti-collision lights-

a. Navigation lights are used to identify an a/c path by observer b. A+ LH & RH lights are of 3 candles & Rear lights are of 5 candles c. A+ LH & RH lights are of 5 candles & Rear lights are of 3 candles

d. All of the above

15. Capacity of battery depends on- (Pallett Page 21). a. Material of electrode b. Size of electrode c. Level of electrolyte D. All of the above

16. Where initial current high & circuit contain high capacitive load, safety device used: pallett 112 a. Current Limiter b. Limiting Resister c. High Rupturing Fuse d. Air Fuse

17. In which side equalizer rings are connected when generators are working in parallel- pallett pg 18 a. Negative terminal of both generators b. Negative and Positive terminal of the generator c. Positive terminals of both generators

18. When full voltage applied on a synchronous motor, Input voltage know as- (B.L.Thareja Vol II, Chap 38 Page 1501)

a.Breakaway Torque b. Running Torque

c.Pull in Torque

d.Pull out Torque

19. Two material A and B have resistance Temperature Coefficient of 0.004 and 0.0004 at a temperature, in what proportion A and B join series to produce a circuit having a temperature coefficient of .001? a. 2 b.3 c.4 d. 5 20. Most common cause of false warning in continuous Loop fire detection system FAA a. Improper routing or clamping of loops b. Moisture

c. Dents, Kinks or crushed sensor section

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21. A Mono-stable Multi vibrator circuit (B.L.Thareja Vol IV, Chap 65 Page 2440)

a. Has no stable state b. Gives two output pulse for one input trigger pulse c. Return to its stand by states automatically d. Has no energy storage element.

22. Varistor is a solid state device it is primarily consist of- : (BLT Part 1Page 29) a. Zink oxide b. Carbons c. Metal oxide d. Silicon carbide 23. If temperature increases the resistance of ..Decreases a. Pure metal b. Electrolyte

c. Alloy

d. All of the above

24. Which is not the part of Secondary Bonding in aircraft: (Pallett Page 94 Ch-5) a. Junction Boxes b. Door plates

c. Flight Control Surface

d. Metal conduit

25.Out of adjustment in voltage regulator due to- Pallett page 10-11. a. Fault in field excitation b. Internal grounding of coils c. Open circuit in voltage regulator d. All of the above

26. Mark the correct statement regarding rain replant system- Pallett page 179. a. Approximately 5 c.c. fluid flows through the nozzle for approximately 0.25 seconds. b. Approximately 5 c.c. fluid flows through the nozzle for approximately 0.025 seconds. c. None of the above 27. Smoke detectors use: Pallet-166

a. capacitor discharge tubes

b. spot fire detectors

c. continuous fire wire elements d. photo diodes

28. In a CSD unit, the control cylinder is mechanically coupled to the: Pallet-221 a. variable displacement unit b. fixed displacement unit c. governor d. none of the above

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29. Circuit breakers and fuses are located: Pallet, P-115

a. generally far from the power source b. close to the power source c. at any location compatible to the particular unit d. so as not to be exposed to heat of any kind 30.. Temperature compensation capacitor is made of: (Ref. Grob., 420)

a. mica b. chip c. paper d. ceramic

31. In ATA 100 code wire specification, No. 3 & No. 5 indicates respectively : Pallett- Page-185 a. Circuit function & Cable segment i.e the portion of the cable between two terminals or connections. b. Circuit segment & Cable function i.e the portion of the cable between two terminals or connections. c. Circuit unit number and cable radius measured in AWG. d. Cable numbering which is used to differentiate between cables not having a common terminal in the

same ckt and the cable size corresponding to AWG sizes. 32. The Anti-collision beacon that employs a V- shaped reflector is: (Pallett Page 146)

a. Rotated at about 45 rev/min b. Rotated at 70-75 cycles/min c. Rotated at 80-90 cycles/min d. Rotated at 90-cycles/min

33. If a Lead acid battery is not retaining charge, probable cause may be: BLT- 1 Page 362 chapter 9 a. Set for high charging rate b. Low electrolyte c. Defective cell

d. Electrolyte level is below the plate

34. While utilizing co-axial cable, it should be secured firmly along its entire length and supporting clamp are placed: (FAA Airmen Question Bank)

a. at 1 feet interval b. at 2 feet interval c. at 4 feet interval d. wherever cable defines 35. In aircraft ESDS devices after removing from aircraft & taking for line maintenance: (Esmin page 274)

a. ESDS should be shorted by wire b. ESDS should be shorted by shorting-clips c. Both a and b

36. In a battery, temperature sensing device. (Pallett Page 27) a. prevents the battery from overcharging b. in the event of a temperature increase it will automatically disconnect the battery from charging c. as in (a) & prevents from thermal runaway d. All of the above

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37. The mechanical power developed by the armature of a D.C motor is equal to: BLT II page 1028 a. armature current multiplied by back e.m.f b. power input minus losses c. power output multiplied by efficiency d. power output plus iron losses

38. When external AC power is connected to TRU, its output: (Ref. EHJ Pallet, 63)

a. energies d.c. control relay circuits b. is connected to d.c. bus bar to operate d.c. consumers c. both a & b are correct d. is used sparingly on ground

39. Power transformer has : a. voltage constant b. current constant c. power constant d. Main flux constant

40. If an alternator or generator get overloaded Check!!!! a. it will be disconnected from over load circuit b. thermal switch will automatically disconnect it from over load c. overload condition can be reduced by resistance d. Drive shaft will be disconnected automatically

41. The effect of increasing the length of air-gap in an induction motor will be to increase the : BLT II Page 1309. a. power factor b. speed c. Magnetizing current d. air gap flux

42. In a very simple system, busbars are made up of : (Pallett- page 76 Chapter 5)

a. strips of interlinked terminals b. thick metal strip c. thick metal rod d. Both (b) and (c) 43. In servomechanism, which type of servomotor is usually preferred? Pallett (motors)

a. one phase b. Two phase c. Three phase d. both (a) and (b)

44. Igniter plug has more advantage over spark plug:

a. It sustain high voltage than spark plug b. it sustain high current than spark plug c. It has high energy for prolonger time

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45. Which one can be operated both manually and electrically: (Palette- Page 99 Chapter 6)

a. Proximity switch b. Rotating switch c. Micro-switch d. Thermal switch

46. what indicates the number of circuits each pole can complete through the switch : (Palette- Page 100 Chapter 6).

a. Pole b. Throw c. Both (a) and (b) d. Bi-pole

47. Method employed in CRT to generate free electrons: (BLT Chapter 73- Page 2695)

a. Heat energy (Thermionic emission) b. Speed c. Kinetic energy d. Light energy

48. Mark the correct statement related to NPN Transistor: V.K Mehta Page 755 a. Collector is highly doped for supply of carrier b. Base is least doped and has thin layer. C. Emitter has relatively low voltage

49. White crystals on Ni-Cd battery is formed due to: ( Pallett Chap-01 page 23 ) a. Over charging b. Under Charging c. Charge can be checked by voltage test 50. State of charge of Nickel Cadmium battery can be determined by: (Pallett- Chap- 01 Page 23)

a. Electrolytic level

b. By relative density of the electrolyte c. Battery Voltage check

d. Battery voltage on-charge condition and the electrolyte should be at maximum level.

51. A non-return valve fitted in the air inlet prevents: (Pallett Chapter 01 Page 24) a. air from cabin to enters the battery ventilation chamber and continues through to the outside of the aircraft. b. Fumes and gases from escaping into the aircraft when no pressure differentials exist on the ground. c. Leakage of battery fumes by pressure differential.

52. In a faulty circuit with bad insulation: CHECK!!!

a. Low intensity blub will glow dimly b. No effect on voltage drop c. current will go back to source d. both (a) and (b)

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53. Copper bonding is used on: Esmin page 77

a. Stainless steel b. Aluminium c. All metals parts d. both (a) and (b) 54. In order to achieve the best possible commutation, commutator are employed with: Pallett page 7 a. A support ring, or end frame, that can be rotated to alter the position of the brushes

relative to the magnetic neutral axis. b. brushes with short leads or "pigtails" c. Flexible copper braid moulded into the brush during manufacture. 55. If Ni-Cd battery is completely discharged and charged to 140% of charging :

a. Deep cycling b. Fresh charge c. Battery cycling 56. Mark the correct statement regarding landing horn: Pallett Page 176

a. Horn reset when thrust lever idle & flap position is up b. horn reset when final phase of landing & flap down position

57. Real load in Alternator can be determined by: Pallett a. Varying the speed of drive unit b. varying the value of voltage regulator c. varying the current in the field winding d. None of the above

58. Which one is the most accurate type of frequency measuring instrument? FAA-Jeppessen a. integrated circuit chip having a clock circuit b. Electro dynamo meter using electromagnetic fields c. Electomagnets using one permanent magnet

59. Mark the correct statement about TRU and static inverter (pallet) Check!!! a. TRU is connected to respective DC/AC busbar b. Static inverter directly connected to battery c. TRU connected to the battery d. Static inverter connected to non-essential bus bars,

60. When both the inputs are high and Output are low: BLT a. Positive NOR & Negative NAND b. Positive OR & Negative AND c. Positive NOR & Negative NAND d. Positive NAND & Negative NOR

61. MTCS regarding CB, CE & CC: BLT

a. Power Gain: Moderate Highest Lowest b. Power Gain: Highest Moderate Lowest c. Power Gain: Moderate Lowest Highest

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62. Which memory is a read-only memory? Esmin

a. Dynamic b. Static c. ROM d. EPROM

63. 8-Bit register that store the memory output when a memory read operation is performed, is known as: a. Program counter b. Memory data register c. Memory address register d. Instruction register

64. When a transformer designed for low frequency is used with higher frequency. Palltte 63

a. in this case the primary current will be reduced and the transformer will function normally

b. in this case the primary current will be high and there is a risk of excessive heat generation in the

primary winding and subsequent burnout.

65. In an intrinsic semiconductor, Fermi level : BLT 4 ch-1 pg 2035 a. Lies in the middle of the energy gap i.e. midway b/w the conduction and valence band. b. Lies in the middle of insulator and semiconductors.

66. Anti-skid system control affected by a. A switch in the cockpit

67. Regarding LED MTCS: a. For an LED to conduct, the applied voltage must be connected in the forward-biased condition b. For an LED to conduct, the applied voltage must be connected in the reversed-biased condition c. None of the above

68. MTCS: a. When open circuit occur in a circuit, current return into the system b. When short circuit occur current return to system c. As in b) & voltage low level condition light brightness is low d. As in b) and c)

69. The iron loss of a transformer at 400 Hz is low. Assuming that eddy current & hysteresis loss vary as the square of flux density. The iron loss of the Transformer at rated voltage but at 50 Hz would be-------- watt: BLT-1209

a. 80 b. 640 c. 1.25 d. 100 70. In case of magneto system : pallett page 158 a. When switch is in OFF position, circuit completes to ground. b. When the switch is ON condition circuit connects to ground. c. None of the above.

71. Mercury switch is used for: pallett page 104 a. When the angular position of a component must be controlled within a narrow band of operation. b. The angular position of a component has no effect on the switch.

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72. In the case of CRT: Esmin

a. The video data received from a radio antenna is conveniently in what is termed rho theta form. b. Received data is still in rho-theta form but displayed x-y format c. As in a) and b).

73. In the case of split bus bar method: page 81 pallett Check!!! a. Used between non-parallel generator b. In the case both the generator fails the main DC busbar will become isolated from the essential DC busbar

74. MTCS (bus II amber) when: page 80 pallett a) If both respective GCB and BTB are open b) If both respective GCB and BTB are open c) Either respective GCB and BTB are open

75. In case of servomechanism for correct phase used: Autoflight control (servo mechanism) a. Phase correction transducer b. Differentiator

76. In case of real load unbalance is determined by means of : Pallet page 48 a. Speed governor b. Error detector c. Current transformer d. Magnetic amplifier

77. In a generator what eliminates possible sparking to the brush guide caused by the movement of the brush within the holder: FAA

a. Brush spring tensions. b. The brush pigtails c. Undercutting of the mica on the commutator

78. The voltage in an ac transformer that contains twice as many as loops as the primary will be: FAA a. Greater & the amperage less than in the primary b. Less & the amperage greater than the primary.

79. In the case of synchronous motor : Pallett page 143 a. F=PN/60 (P:no. of pairs of poles, N:synchronous speed, F: power-supply frequency ) b. b. F=60/PN c. c. F=P60/N

80. Intrinsic semiconductor at absolute temperature behaves as: BLT a. Conductor b. Insulator c. None of the above

81. When constant frequency generators are operating in parallel the shearing of a real load is controlled by : pallet 221 a. Varying the excitation current in each generator b. Varying the output speed of the CSD unit c. By shedding certain load.

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82. The primary reason for providing compensating winding in a DC generator is to: BLT-965 a. Compensate for decrease in main flux b. Neutralize armature mmf c. Neutralize cross magnetizing flux d. Maintain uniform flux distribution

83. The main function if interlope is to minimize ________between the brushes and the commutator when the DC machine is rotated: BLT-965

a. Friction b. Sparking c. Current d. Wear and tear

84. The moving system of an indicating type of electrical instrument is subjected to: FAA a. A deflecting torque b. A controlling torque c. A damping torque d. All of the above

85. The meter suitable for only direct current measurement is: FAA a. Moving-iron type b. Permanent magnet type c. Electromagnet type d. Hot wire type

86. The ratio of the true power to the apparent power in an a.c circuit is known as: Pallett a. Reactive power b. Power factor c. Real power

87. The phase voltage of a three phase star connected a.c generator is: Pallett

a. Equal to line voltage

b. Greater than line voltage

c. Less than line voltage

More questions with figures:

1. Identification of coaxial cable

2. Continuous loop detector

3. Hartley and colpitt oscillator

4. Wattmeter

5. Switches (Pole-throw)

Best of Luck

dgca ame es paper oct-2013

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