Cat® Digital Voltage Regulator Caterpillar

Illustration 1	g01425634

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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.

Refer to Specifications, Systems Operation, Testing and Adjusting, RENR7941, "Earlier CDVR Dissimilarities " for part number information of the earlier version of the CDVR.

1. Verify that the voltage regulator is programmed for droop mode. If the voltage regulator is programmed for droop mode, go to step 2.

2. Verify that the voltage regulator droop setting is not adjusted to 0% droop. If the droop setting is adjusted to 0% droop, increase the setpoint above 0%. If the droop setting is adjusted to above 0%, go to step 3.

3. Check for an open in the circuit connected to voltage regulator terminals P12-1 and P12-2 and CT2. If there is an open circuit, repair as necessary. If there is not an open circuit, go to step 4.

4. Verify that all connections are correct according to Testing and Adjusting, "Wiring Diagrams". Verify that the "Curren Transformer" (CT) is not installed backwards, or on the wrong phase. Verify that the "Potential Transformer" (PT) phase rotation is correct. If connections and installations are correct, go to step 5.

5. Verify that the load that is being applied to the generator for droop testing is not a purely resistive load. If only a resistive load is being applied to the generator, apply an inductive load and retest. If the load being applied to the generator is inductive, go to step 6.

6. Verify that the current sensing transformer that is being used is compatible with the voltage regulator. A current sensing transformer with a 1-ampere output rating would produce little droop since the voltage regulator has a 5 A current transformer input. If the current transformer input is incorrect, replace the current sensing transformer for compatibility. If the current transformer input is correct, go to step 7.

7. Check the wiring to the switch input ("programmable input") if that input is configured for line loss compensation.

8. If all of the previous steps fail to correct the malfunction, replace the voltage regulator.