ELEMENT 8I6679 - Caterpillar

Except for the oilfield generators, all Cat® generators are provided with voltage regulators. The voltage regulator controls the generator output voltage. Refer to the appropriate price list to view the available IVR and CDVR options for Cat® generators.Illustrations 1 through 4 show the different types of voltage regulator adjustment controls.The VR3 regulators and the VR3F regulators have voltage droop capability (1). The VR4 regulator does not have a voltage droop capability. The VR4 regulator is not designed for parallel applications.The VR3 regulators, VR3F regulators, and VR4 regulators have the voltage level control (2).The VR3 regulators and VR4 regulators have a voltage gain capability (3). The VR3F regulator does not have voltage gain capability.Voltage droop, voltage level, and voltage gain are controlled by multiturn potentiometers. The adjusting screws on the potentiometers do not have a fixed stop. When the potentiometer reaches the end of adjustment, a ratchet action begins. The beginning of a ratchet action can be felt with the adjusting tool. The adjusting screw can be turned past the potentiometer stop (ratchet action) without further changing the potentiometer setting.
Illustration 1 g00626329
Adjustment Controls of the VR3 Regulator
(1) Voltage droop potentiometer
(2) Voltage level potentiometer
(3) Voltage gain potentiometer
(4) Fuse(s)
Illustration 2 g00626331
Adjustment Controls of the VR3F Regulator
(1) Voltage droop potentiometer
(2) Voltage level potentiometer
(4) Fuse(s)
Illustration 3 g00626398
Adjustment Controls of the VR4 Regulator
(2) Voltage level potentiometer
(3) Voltage gain potentiometer
(4) Fuse(s)
Illustration 4 g00626333
Digital Voltage Regulator (DVR)
(5) Display
(6) Function key
(7) Scroll down key
(8) Scroll up key
(9) Keypad
(10) J1 connector
(11) Screw terminalsThe digital voltage regulator (DVR) is a microprocessor-based voltage regulator. The parameters are preset at the factory or the parameters can be modified to meet the specific requirements on the site. Certain system parameters can also be monitored on the display (5) of the DVR. Keypad (9) is used to change the information that is shown on the display (5). J1 connector (10) is used to join the DVR to a personal computer. Screw terminals (11) are used to join the DVR to the generator and various customer options.Adjustment Procedure for the Voltage Regulators
VR3 Regulator
Note: The VR3 regulator is protected by a fuse or fuses. The VR3 regulator also has a solid-state overcurrent protection. If a fuse becomes open, contact a Caterpillar dealer.
Remove the access panel of the generator.
Loosen the locknut on the voltage droop potentiometer (1). Remove the protective screw from the voltage level potentiometer (2). Remove the protective screw from the voltage gain potentiometer (3).
Turn the voltage droop potentiometer (1) counterclockwise to zero droop. Tighten the locknut. The Voltage droop potentiometer (1) is located next to the regulator.
Remove the protective screw from the voltage level potentiometer (2). Remove the protective screw from the voltage gain potentiometer (3).
Turn the voltage gain potentiometer (3) counterclockwise to zero. Then, turn voltage gain potentiometer (3) to about 1/4 of full range of clockwise travel.
Perform required maintenance on the engine before you start the engine.
Start the engine. Allow the engine to warm up. Refer to the Safety Section, "Engine Starting".
Increase engine speed to full governed rated speed (high idle).
Observe the voltmeter reading. If