Publication: Rev First Printing 01/93 Copyright

9 2709 00 990 G Revised 09/01 1993-2001

Basler ElectricPhone 618 654-2341Route 143 Box 269Highland IL 62249 USA

Power Systems GroupFax 618 654-2351

http://www.basler.cominfo@basler.com

INSTRUCTIONSFOR

VOLTAGE REGULATORAEC 42-7

9 2709 00 100

GENERAL INFORMATION

DESCRIPTION

The AEC 42-7 voltage regulator is designed foruse on 50/60 Hz brushless generators. Theregulator includes frequency compensation,overexcitation shutdown, a solid-state buildupcircuit, and EMI filtering.

ELECTRICAL SPECIFICATIONSDC Output PowerMaximum continuous: 7 Adc at 42 Vdc10 second Forcing: 15 Adc at 90 Vdc (at

240 Vac supplyvoltage)

Exciter Field DC ResistanceMinimum: 6 ohmsMaximum: 105 ohms

AC Power Input

Operating Range: 220 to 260 VacPhase: 1-PhaseFrequency: 50/60 HzBurden: <900 VA

Sensing Input: 200-252 Vac ±10%

2-phase, 50/60 Hz at<1 VA Burden

Voltage Adjust Range:180 to 277 VacRegulation Accuracy: <1% No-load to Full

load, Average SensingParalleling: Input for 5 Vac from

External CT / BurdenResistor to allow 10%Droop

Response Time: Less than 1.5 cyclesfor ±5% change insensing voltage. Link(T C) and AdjustableStability to optimize re-sponse

EMI Suppression: Internal EMI filterFrequency Compensation Rate:

Twice volts per Hertz(See Figure 1 forcurve)

Overexcitation Shutdown:Time Delayed: Inverse Trip Range: From no trip @ 50 Vdc

to instantaneous at100. (See Figure 2.)Disable link terminals (N D) provided for par-allel operation.

Voltage Buildup Internal provision forautomatic buildupfrom 6 Vac, “SoftStart”

Power Dissipation 20 watts (typical)

PHYSICAL SPECIFICATIONSTemperature:Operating: -20°C to 60°C

(-4°F to 140°F)Storage: -40°C to 85°C

(-40°F to 185°F)Vibration: Withstands 1.3 G's at

2 to 27 Hz.; 0.036"double amplitude at27 to 52 Hz.; and 5G's at 52 to 1000 Hz

Shock Withstands up to 20G's in each of threemutually perpendicu-lar axes

Weight 0.68 kg. (1.5 lbs.)

FREQUENCY COMPENSATIONThe frequency compensation characteristic ofFigure 1 is used to improve system load pickupperformance by restraining voltage recoveryuntil frequency has also started to recover.

The regulator is shipped from the factory set ata 47 Hz”'corner frequency” for 50 Hz systems.For 60 Hz systems, a 57 Hz corner frequencyis achieved by removing the “50-50" externallink.

OVEREXCITATION TIME DELAYIf exciter field voltage exceeds 52 ± 2 Vdc, theregulator automatically removes the fieldcurrent, after a time delay. The time delay isinversely proportional to the magnitude of thedetected field over voltage condition up to 95±5 Vdc point. Beyond 95 ±5 Vdc, the fieldvoltage is removed at a much faster rate. Thisshutdown function may be disabled for paralleloperation by linking terminals N and Dtogether.

INSTALLATIONMOUNTINGThe regulator may be mounted on the gen-erator in any convenient position. Refer tooutline drawing Figure 3. Figure 4 provides thedrilling template.

EXCITER FIELD POWER CIRCUIT

Connect regulator + wire to the brushless exciterfield F+ terminal, and the - wire to the field F-terminal. Refer to Figure 5.

If the exciter field resistance is less than 6ohms, and if the full-load field current does notexceed the maximum continuous current ratingof the regulator (7 Adc), a resistor of sufficientwattage must be added in series with the field tobring the total resistance to 6 ohms.

POWER INPUT

Connect wiring as shown in Figure 5. Power forthe regulator is derived from the generatorauxiliary winding, connected to wires 3 and 4.The operable power input range is 220-260 Vac.

SENSING INPUTS

For sensing, wires U and V are connected to thegenerator phase U and phase V respectively.Wires X and Y are connected to the oppositeends of the U and V phase coils, or commonedtogether at the neutral (star) point.

QUADRATURE DROOP INPUT

When paralleling is required, a currenttransformer (CT) and variable burden resistor(rheostat) should be connected to terminals Aand B. The ratio of the CT and the maximumvalue of the burden must be chosen so that atmaximum current the voltage applied toterminals A and B does not exceed 5 Vac rms.A suitable value of burden would be a rheostatadjustable from 0 - 5 ohms (10 Watts) for a CTwith a 1 Aac secondary current at full load.These terminals may either be linked or leftopen when paralleling is not required.

FUSES

It is recommended that a fuse or fuses with highinterruption capability be installed per the inter-connection diagram. A suitable fuse type wouldbe LittelFuse (type 3AG, rated 250 Vac, 6.3 A,“Slo-Blo.” Dimensions are 6.3 mm x 32 mm (1¼" x ¼").

CAUTIONThe DC resistance of the exciter field mustbe equal to or greater than 6 ohms and lessthan 100 ohms.

NOTEFuse(s) MUST be installed per theinterconnection diagram to avoidinterrupting field current directly.

NOTEThe ground terminal must be bondedeither to a metal ground by the mountingscrew or by means of a cable to the mostsuitable earthing point available close tothe regulator.

VOLTAGE ADJUST RHEOSTAT (V)

An internal screwdriver preset (V) providescoarse adjustment of generator output voltage.A clockwise adjustment of V increases voltage.The voltage regulator is shipped from the factorywith a link across terminals P and Q. If a re-mote voltage adjust rheostat is used, the linkshould be removed and the rheostat connectedto P and Q. A 1 kilo-ohm, 0.5 W potentiometerwill provide a 'fine' voltage range adjustment ofapproximately ±10% over most of the coarserange of adjustment. See Figure 5, Intercon-nection Diagram.

V/HZ "CORNER FREQUENCY" SELECTION

For 50 Hz systems, the regulator is preset at thefactory for a 47 Hz "corner frequency" with a linkfitted across terminals “50". If operation at 60Hz is required, this link should be removed; the"corner frequency" is now set to 57 Hz. Do notoperate the system at 60 Hz with the 50 Hz linkstill in place.

OVEREXCITATION SHUTDOWN

Overexcitation shutdown is provided to removeoutput excitation should the regulator outputvoltage exceeds 52 ± 2 Vdc for a sufficient time.The inverse-time-delay curve is shown in Figure2. For voltages above 95 ±5 Vdc, there is asecond and much shorter inverse time curve.

After output power is removed, the regulator canbe reset by decreasing the input voltage to lessthan 6 Vac for a minimum of 2 seconds. Thismay be accomplished by stopping the primemover or interrupting the regulator input bymeans of a reset switch.In cases where the generator is operating in aparallel mode, it is sometimes consideredundesirable to allow the regulator to shut down,which may cause the generator to be ”motored.”Terminals N and D may be linked together toprevent overexcitation shutdown. Note, how-ever, that continuous running at output levelsgreater than the continuous rating may result ineventual regulator failure, and that other meansshould be employed to protect the system.

OPERATIONGENERAL

The following system operation proceduresprovide instructions for adjusting the AEC 42-7voltage regulator. Symptoms resulting from afaulty regulator and certain generator systemproblems are included, together with suggestedremedies.

Complete the following steps before proceedingwith system startup.

PRELIMINARY SETUPa. Verify that the voltage regulator

specifications conform with the generatorsystem requirements.

b. Ensure that the regulator links are fittedcorrectly where required, as follows.

(1) If the remote voltage adjust rheostat isnot required, ensure terminals P andQ are linked together.

(2) If a 57 Hz corner frequency for 60 Hzsystems is desired, ensure the”'50 -50" link is removed. If a 47 Hz cornerfrequency for 50 Hz systems isdesired, ensure the “50 - 50" link isconnected.

(3) If the system is to be run in parallel,consider whether shutdown of thegenerator's excitation is acceptable. Ifnot, ensure that the link betweenterminals N and D is in place.

c. Ensure that the voltage regulator is cor-rectly connected to the generator system:F+ to field positive, F- to field negative, andterminals 3 and 4 to the auxiliary windingsupply. It is vital that the sensing con-nections are correctly made to all 4 wiresU, V, X, and Y. Ensure that the metal ringtag at one mounting hole is bonded toground via either a metal screw or shortlength of cable.

d. Install the fuses as directed in the previoussection.

e. Set the regulator and external voltageadjust, if used, as follows:

Regulator Volts Adjust 'V' Fully CCWRemote Volts Adjust CenteredStability Adjust 'S' Centered

SYSTEM STARTUPa. Perform the preliminary setup procedure

checking wiring carefully.

b. Start prime mover and bring up to ratedspeed.

RESULT: The voltage should build up to lessthan nominal value. c. Slowly adjust the regulator voltage adjust V

until the generator output voltage reachesthe nominal value. Should a low frequencyoscillation or hunting be present on thegenerator output voltage, adjust stabilitycontrol S to cause this to be damped out.In general, clockwise increases thestability. But in some cases, too far CWmay start to reduce stability again, and willinvariably slow the response of thegenerator to load changes. An optimumsetting method is to adjust S slowly CCWuntil the generator voltage just starts tobecome unstable. Then turn it up to ¼ turnCW from that position.

d. If used, adjust the external voltage adjustrheostat to fine trim the voltage to the exactvalue desired.

RESULT: Voltage should now have built upand be stable at the desired value. If voltagedoes not build up to rated value, check thatthere is no short circuit or excessive loadpresent on the generator lines. If a minimumresidual of 6 Vac is not present, perform “FieldFlashing” as ex-plained later.

e. Check regulator under normal operating

and loading conditions.

RESULT: Voltage regulation should be betterthan ±1.0% no-load to full-load. If regulation isnot within this range, check the following:

(1) Voltage reduction under loads of cosq >0.0 may be due to speed reduction dueto loading of the prime mover. This maybe causing the frequency compensation(V/Hz) circuit to reduce voltage at aspeed which is less than the "cornerfrequency".

(2) Replace voltage regulator.

FIELD FLASHING

When the regulator is operated with thegenerator for the first time, the polarity ofresidual magnetism may be reversed or toosmall to achieve the necessary buildup voltagefor the regulator. If reversing the field con-nections does not induce buildup, and theresidual voltage is less than the specified valueof 6 Vac, shut down the prime mover and pro-ceed with the following steps:

a. With the prime-mover at rest and theregulator field output wires disconnected,apply a DC source (NOT ground-ed) of notmore than 24 Vdc with Positive to F+ andNegative to F-, in series with acurrent-limiting resistor of 3-5 ohms. (Theset battery is a suitable source.)

b. Allow approximately 3 seconds beforeremoving the DC source.

c. With the voltage regulator disconnected(wires 3 and 4), start the prime mover andmeasure the “residual” voltage available atthe auxiliary winding. If this voltage isgreater than 6 Vac, reconnect voltageregulator, and voltage buildup should besuccessful. If less than 6 Vac is measured,repeat field flashing procedure.

d. If repeating steps a and b does not resultin generator voltage buildup, and residualis greater than 6 Vac, replace voltageregulator.

MAINTENANCE

PREVENTIVE MAINTENANCE

A periodic inspection of the unit should be madeto ensure it is kept clean and free fromaccumulations of dust and moisture. It is vital toensure that all the wire and terminal connectionsare kept sound, secure and free of corrosion.

OPERATIONAL TESTa. Connect the test setup as shown in Figure

6. Do NOT apply power. Ensure the lightbulbs are rated 120 volts and less than 100watts. Alternatively a single 240 V bulbmay be used.

b. Adjust the internal (V) and external voltageadjust potentiometers fully CCW.

c. Apply 240 Vac, 50/60 Hz power to theregulator.

d. Slowly turn the internal voltage adjust V inthe CW direction.

WARNING!If a glass fuse is used, itshould be enclosed for safety.

CAUTIONMeggers and high-potential testequipment must not be used.Incorrect use of such equipment could

NOTEAll AC voltage readings are to be takenwith an 'average' reading voltmeter ratedspeed.

Figure 1. Frequency Compensation CurvesFigure 2. Typical Inverse Time Delay Characteristic

Curve

V S

� � � �

AEC 42-7

QPBA

50

50-+4

3

VYXU

20 AWG LEAD WIRE

125mm (4.912")

(4.528")140mm

115mm

(5.512")

100mm (3.928")

GROUND CONNECTIONAT THIS MOUNTING HOLE

4mm (0.157")17mm (0.667")

77mm (3.02")

33mm (1.29")Figure 3. AEC 42-7 Outlined Diagram

RESULT:

(1) Before fully CW is reached, the light

bulb should reach full brilliance to signifythe regulator is controlling correctly.(2) At this regulating point, a small

change in either of the adjustmentsshould result in the light bulb beingturned full on or off.

Figure 6. Test Setup Diagram

Figure 5. Interconnection Diagram, 480 Vac Generator