DRIVE SHAFT GUARD GROUP 2G1755 - Caterpillar

The Cat VR6 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.
Check if there is the jumper between terminals 4 and 7.Expected Result:There is a jumper that is placed between terminals 4 and 7.Results:
YES - If a remote voltage adjust potentiometer is NOT used, the jumper is properly installed. Proceed to test step 4.
YES - If a remote voltage adjust potentiometer is used, the jumper should be removed from terminals 4 and 7. In this case, the remote voltage adjust potentiometer should be connected to terminals 6A and 7. Proceed to test step.
NO - There is no jumper between terminals 4 and 7. The regulator may go into the overexcitation shutoff.Repair: Verify the wiring schematics. Install the jumper in accordance with the wiring schematic.STOPTest Step 4. CHECK THE RESISTANCE OF THE REMOTE VOLTAGE ADJUST RHEOSTAT
Ensure that the generator set is stopped.
Disconnect the wires from terminals 6A and 7.
Measure the resistance of the remote voltage adjust potentiometer while the potentiometer is being adjusted over the operating range.Expected Result:The resistance should be between zero (0) Ohms and 10 K Ohms 0.5 K Ohm.Results:
Yes - The resistance increases smoothly within the specified range. Proceed to test step 5.
No - The resistance is not within the specified value. The resistance jumps to a high value when the potentiometer is adjusted.Repair: Replace the remote voltage adjust potentiometer.STOPTest Step 5. CHECK CONNECTIONS FOR THE DROOP CURRENT TRANSFORMER (CT)
Stop the genset.
For a 1 A CT, verify that the connections are to terminals 5 and 6.
For a 5 A CT, verify that the connections are to terminals 5A and 6.Note: For troubleshooting purposes, the voltage regulator can be operated when the droop CT is disconnected. However, the droop CT secondary wires must be connected together.
Verify that the polarity connection of the droop CT is connected to terminal 6.Expected Result:The connections are correct.Results:
YES - The connections are correct. Proceed to test step 6.
NO - The connections are not correct or the connections are impossible to verify.Repair: Run an individual genset with a reactive load. If the voltage increases as the reactive load increases, the CT secondary is not connected properly. Stop the genset and reverse the lead connections.STOPTest Step 6. CHECK ENGINE RPM
Start the genset.
Run the genset at no load.
Monitor the engine speed.Expected Result:Engine speed is stable.Results:
YES - Engine speed is stable. Proceed to test step 7.
NO - When the engine speed is unstable, the frequency will be also unstable. The unstable frequency causes the voltage to become unstable as well.Repair: Troubleshoot the engine RPM. Refer to the appropriate engine service manual.STOPTest Step 7. VERIFY THE STABILITY ADJUSTMENT SETTING
Readjust the stability adjustment. Refer to the Testing and Adjusting, "Stability - Adjust".Expected Result:Voltage has stabilized.Results:
YES - The voltage is stable. Add the load to the generator. If the voltage remains stable, the problem has been resolved.