SCREW-PAN HEAD 1842472 - Caterpillar

An improved procedure can be used for easier adjustment of the voltage gain on all Statically Regulated Controlled Rectifier (SRCR) and Statically Regulated Brushless Excited (SR4) Generator Sets. The new procedure, which is given in this article, is also given in the Operation, Lubrication and Maintenance Guide for SRCR and SR4 Generator Sets, SEBU5717. Also, the later decal (black letters on white back ground) for initial adjustment of the voltage control, has the new procedure.
It was some times difficult to adjust the voltage gain with the former procedure. The improved procedure for adjustment of voltage gain, which follows, is adaptable to all SRCR and SR4 Generator Sets.
Procedure To Adjust Voltage Gain
1. Remove the access panel from the left side of the generator.2. Loosen the locknuts on the voltage droop, voltage level, and voltage gain controls.3. Turn the voltage droop control counterclockwise to get zero droop and tighten the locknut.4. Turn the voltage gain control counterclockwise to its zero position, and then turn the gain control to about one-fourth of it's full range of clockwise movement.5. Do all necessary maintenance on the engine before it is started.6. Start and operate the engine until it is at normal operating temperature.7. Increase the engine RPM to high idle (full governor RPM).8. Read the voltmeter. If it is not at the desired voltage, adjust the no load voltage with the voltage level control.9. Close the circuit breaker and gradually put the full load on the system. Adjust the governor control until the frequency shown on the Hertz meter is the same as given on the name plate.10. If the voltmeter indication increases with a full load on the system, turn the voltage gain control a very small amount in the counterclockwise direction. If the voltmeter indication decreases with a full load on the system, turn the gain control a very small amount in the clockwise direction.
11. Remove the load from the system and adjust the voltage level control, if necessary, to get the desired voltage.12. Put a load on the system and read the voltmeter. If necessary, do steps 9 thru 12 again, until the no load voltage is the same as the full load voltage.13. Tighten the locknuts on all the controls and install the access panel.