PLUNGER AS 8C9778 - Caterpillar

Illustration 1 g01425625
The Cat Digital Voltage Regulator presents an electrical shock/electrocution hazard. This hazard will cause serious injury or death.Service by trained personnel only.The terminals and heat sinks are live at hazardous voltages when power is applied and for up to 8 minutes after power is removed.
Verify that the voltage adjustment is not set too high. OK - If the voltage adjustment is correct, go to step 2.NOT OK - If the voltage adjustment is too high, adjust the voltage to the correct set point. STOP.
Verify that the sensing potential transformer (if used) has the correct turns ratio. OK - If the sensing potential transformer is correct, go to step 3.NOT OK - If the turns ratio of the sensing potential transformer is incorrect, replace the sensing potential transformer with the correct one.STOP.
High generator output voltage may occur when operating in droop mode with a capacitive load. If the high voltage condition is not caused by the droop function, go to step 4.
High generator output voltage may occur when operating in line drop compensation mode with a large generator load. If the high voltage condition is not caused by the line drop compensation function, go to step 5.
Verify that the fuses for the sensing potential transformer (if used) are not open. OK - If the fuses for the sensing potential transformer are correct, go to step 6.NOT OK - If the fuses for the sensing potential transformer are open, replace the fuses. STOP.
Verify that the auxiliary input voltage going to the voltage regulator is present or abnormally high. Higher than normal voltage at this input will cause a higher than normal generator voltage. If voltage is present on the auxiliary input, remove the input by removing the wiring going to the voltage regulator. If the wire is removed and the generator voltage returns to the desired level, determine the origin of the voltage. The source of the voltage could be a VAR/PF controller or another control that is connected to the unit. If the auxiliary input voltage is not present or abnormally high, go to step 7.
Replace the voltage regulator.