Digital Voltage Regulator Caterpillar

Note: Electromagnetic noise spikes can create an erroneous instantaneous trip. Such spikes are often the result of breaker closure. If the digital voltage regulator or any wiring to the digital voltage regulator is in close proximity to a circuit breaker (particularly a medium voltage breaker), this condition may occur. Uninterrupted power systems (UPS), motor drives, and other equipment that generates electromagnetic interference (EMI) spikes or switches large currents must also be avoided. Install the digital voltage regulator in the generator terminal box or in another location away from the offending equipment.

1. Check the wiring.

   1. Stop the generator set.

   2. Check the wiring.

      Expected Result: The wiring is correct.

      Results:

      • OK: Go to Step 2.

      • NOT OK: Shorted F1 and F2 wires will cause the instantaneous trip shutdown fault. Megger the exciter stator. See the proper wiring diagram for details. Refer to Testing And Adjusting, "Wiring Diagrams". STOP.

2. Check the accessory.

   1. Disconnect all accessory wiring from terminals 3, 5, 6, 7, 40, 41, 42, 43, 44, 45, and 50. Remove the serial data link, if installed.

   2. Start the generator set. Operate the generator set with the same conditions that caused the problem previously.

      Expected Result: The generator set operates properly.

      Results:

      • OK: The generator set operates properly. There is a problem with an accessory which has been disconnected. Reconnect one accessory. Operate the generator set again. Continue this process of reconnecting one accessory at a time until the faulty accessory is found. STOP.

      • NOT OK: The generator set does not operate properly. Go to Step 3.

3. Check the nearby equipment.

   1. Identify nearby equipment that could generate EMI spikes.

   2. Move the digital voltage regulator and the wiring to a temporary location away from the offending equipment and operate the generator again.

      Expected Result: The problem has been resolved.

      Results:

      • OK: The problem has been resolved. Find a new permanent home for the digital voltage regulator away from the offending equipment. Shielded wiring should always be used for rheostat inputs when the regulator and/or rheostat are located off the generator. Connect the shield drain wire to regulator terminal 45. Insulate the wiring shield from touching all other objects, including Earth ground.

      • NOT OK: The digital voltage regulator is being subjected to other sources of EMI. On methods to reduce EMI, refer to Systems Operation, "Customer Options", section Remote Installation Notes.