AutomaticVoltageRegulators
VR3
SPECIFICATIONS
RegulationLess than ±1% no load to full load
Regulator driftLess than ±1/2% steady state
Temperature driftLess than ±1% for any 40° C change over theoperating temperature range
Regulator responseMaximum of one electrical cycle (i.e., less than16.6 milliseconds at 60 Hz, or 20 milliseconds at50 Hz)
Regulator sensingThree phase sensing is standard. Single phasesensing can be selected on SE regulators only.
Regulator stabilityRegulator responds to the fundamentalcomponent of the sensed voltage and remainsstable for total harmonic distortion of thegenerator output voltage waveform up to 20%.
Regulator filteringTelephone Influence Factor (TIF) less than 50.Optional filtering packages available to complywith MIL STD 461B Part 9 and VDE 85 level N.
Harmonic toleranceThe AVR will maintain precise control of thegenerator output with up to 20% harmonicdistortion in the generator output voltage.
Voltage adjust range-25% to 10% of nominal
Regulator gainMinimum of +5% to compensate for speed droopgovernors or line losses (voltage droop) betweengenerator and load.
Regulator build-up voltageSE regulators will build up with the generatoroutput voltage as low as 6 vac. No minimumrequirement for PM regulators.
Regulator start-up voltageVoltage overshoot at full throttle engine startingwill not exceed 5% of rated value.
Volts/Hz characteristicLinearly proportional to frequency (8 Volts/Hz on480 Volt/60 Hz basis) over the frequency range of30 Hz to 70 Hz provides matched engine/generator performance for improved block loadperformance.
Reactive droop adjustmentMinimum of 8% droop at full load and 0.8 pf
FEATURES
Self Excited (SE) and Permanent
Magnet Excited (PM) versions available
Regulation better than ±1.0%
Frequency compensated
Overexcitation shutdown
Solid state voltage buildup
Three phase sensing – standard
Compact package size
Moistureproof assembly
Mechanically rugged
Fast response time
Applicable to 50 and 60 Hz systems
Complete line of accessories available
VR3 AUTOMATIC VOLTAGE REGULATORS
STANDARD ACCESSORIES AVAILABLE
Series boostAble to sustain the generator output at 300%rated current for a minimum of ten seconds.Not required for PM.
KVAR/PF controllerProvides KVAR or Power Factor control whengenerator is paralleled with utility.
Remote voltage adjustControls voltage level with a 10 kΩ, 1 wattremotely mounted rheostat.
Manual voltage controlPermits manual regulation of the generator output in the event of a regulator failure.
ParallelingA reactive droop network consisting of a currenttransformer, 8Ω 25 watt rheostat, and controlcircuit allows generator to be paralleled withother generators either in reactive droop or crosscurrent compensation (zero droop) modes.
FilteringComplies with requirements of MIL-STD 461BPart 9, VDE 875 Level N, EN50081-2 andEN50082-2.
SUMMARY OF OPERATING PARAMETERS
SPECIFICATIONS/continued
Overexcitation protectionShuts off generator output when excitationexceeds the nominal values shown below forapproximately 10-16 seconds:
Excitation Type Shutoff Value
SE Excitation voltage > 63 vdcPM Excitation current > 14 amp
Fault protectionTwo fast-acting, high-interrupting capacity fusesare provided to protect the AVR and excitationsystem components against potentiallydamaging electrical faults.
Ambient operating temperature . . -40° C to +70° CStorage temperature range . . . . . . . -40° C to +85° CPower dissipation . . . . . . . . . . . . . . . . . 50 watt (max)Shock . . . . . . . . . . . . . . . . . . . Withstands up to 20 g’sVibration
Withstands 4.5 g’s at frequencies between 18and 2000 Hz in three mutually perpendicularplanes.
Salt spray: . . . Meets MIL-STD-810C, method 509.1Sealing:. . . . . . . . Withstands up to 35 kPa (5.08 psi)Weight: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 Kg
Power Input Output Rating Sensing Reactive Droop Exciter FieldInput Resistance
Max. Min.Continuous Forcing Max VA
Freq Burden VA Min.Type V Hz VA V A V A V Per ø Amps Burden Ohms
240 SE 200/240 50/ 1500 50 10 90 15 200/ 1 0.5 3 3 10volt 1ø 60 240
480 SE 200/240 50/ 1500 50 10 90 15 400/ 1 0.5 3 3 10volt 1ø 60 480
120 PM 70-110 200/ 1500 50 10 90 15 100/ 1 0.5 3 3 10volt 3ø 240 120
240 PM 70-110 200/ 1500 50 10 90 15 200/ 1 0.5 3 3 10volt 3ø 240 240
480 PM 70-110 200/ 1500 50 10 90 15 400/ 1 0.5 3 3 10volt 3ø 240 480
VoltageRating
Max.Ohms
VR3 AUTOMATIC VOLTAGE REGULATORS
OUTLINE DRAWING
For a complete listing of connection diagrams, see Caterpillar publication SENR4794-01 entitled “CONNECTION DIAGRAMS: SR4 GENERATORS VR3 & VR4 VOLTAGE REGULATOR OPTIONS”
01
86.9
113.
8
0202 02
01
1 2 3 4 5 6 7 8 9 10
LEVEL GAIN
20 22 24 26 28 30 F1 F2
FIELDA C I N P U T
9.9
9.9
03
150.
614
0.7
03
191.5201.4
216
INC INC
CONNECTION DIAGRAMS
SELF EXCITED WITH DIRECT CONNECTION TO GENERATOR(240 VAC Sensing)
P.M. EXC WITH DIRECT CONNECTION TO GENERATOR(240 or 480 VAC Sensing)
T8 or T2
CT1
FROMGENERATOR
5 GEN
6 GENR1 8 OHM
2 3 4 5 6 7 8 9
R2 10K OHM
REMOTE LEVELIF INSTALLED(REMOVE LINK 4-7)
LEVEL GAIN
20
VR3 REGULATOR
REGULATORSENSINGLEADS
20KTK-R-12
24 FUSES
22 24 26 28 30 F1 F2
KTK-R-12
F1+
– F2NOTE
DROOP TRANSFORMER CT1 AND DROOP RHEOSTAT R1 MAY OR MAY NOTBE SUPPLIED
L1 EXCITER FIELDR1 DROOP RHEOSTATR2 REMOTE LEVEL RHEOSTAT
C37006P1
CT1 DROOP TRANSFORMER
TERMINAL NUMBERS WIRE NUMBERS POLARITY
REGULATORSENSINGLEADS
T8 or T
5 GEN
6 GEN
2 3 4 5 6 7 8 9
L1F2
T8 or T2
CT1
FROMGENERATOR
5 GEN
6 GENR1 8 OHM
2 3 4 5 6 7 8 9
R2 10K OHM
REMOTE LEVELIF INSTALLED(REMOVE LINK 4-7)
LEVEL GAIN
20
VR3 REGULATOR20
KTK-R-12
24 FUSES
22 24 26 28 30 F1 F2
KTK-R-12
+
–L1
20 GEN
24 GEN
22 GEN
11ABC-10
ABC-10 13FUSES
11 GEN
13 GEN
NOTE
DROOP TRANSFORMER CT1 AND DROOP RHEOSTAT R1 MAY OR MAY NOTBE SUPPLIED
L1 EXCITER FIELDL5 P.M. EXCITER STATORR1 DROOP RHEOSTATR2 REMOTE LEVEL RHEOSTAT
C37057P1
CT1 DROOP TRANSFORMER
TERMINAL NUMBERS WIRE NUMBERS POLARITY
20 GEN
24 GEN
22 GEN
F1
F2
LS12 GEN
VR3 AUTOMATIC VOLTAGE REGULATORS
Materials and specifications are subject to change without notice. The International System of Units (SI) is used in this publication.
LEHX7054 © 1996 Caterpillar Inc. Printed in U.S.A.Supersedes LEHX3239 All rights reserved.
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