DAMPER GP 3823941 - Caterpillar

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Retarding Grid Blower Inverter (RGBI) connections
(12) Three phase cables that are used to supply AC power to the grid blower motor
At the RGBI, disconnect the “BM-A”, the “BM-B” and the “BM-C” three phase cables that supply the AC power to the grid blower motor. Position the cable ends where contact with each other, the RGBI housing or with the cabinet frame cannot occur.
Use a multimeter to measure the resistance between each of the RGBI phase lugs and the RGBI housing:
If all three resistance measurements are high - greater than 2 megohms or “infinite”, the RGBI is most likely not causing the problem. Proceed to the next Test Step “E”.
If any of the three resistance measurements is less than 2 megohms, there is a problem inside of the RGBI. Stop the procedure and call the Dealer Solutions Network (DSN). Indicate the steps that have been taken to find the cause of this problem and the findings that have been discovered.
Connect the megger for testing the insulation of the blower motor cables and the grid blower motor stator windings. Connect the red positive clip to one of the disconnected blower motor cables. Connect the black negative clip to a good cabinet frame ground point.
Ensure that all personnel are not in contact with any of the AC conductors. Ensure that no one is in the area of the grid blower motor or the motor connection in the front of the cabinet.
Set the dial on the megger to 1000 V. Do not test the insulation of the grid blower motor and cables at greater than 1000 V. Press the “START/STOP” button on the megger to start the test. Test the motor cable and the grid blower motor windings at 1000 V. Continue the test until the test voltage has stabilized for 10 seconds. Press the “START/STOP” button to stop the test. The megger will discharge the system. Wait until the voltage readout on the megger display is 0 V. Test Results:
If the insulation test of the grid blower motor and cables indicated a resistance to ground that is much greater than 2 megohms, proceed to the “NO” result below.
A resistance to ground that is very close to 2 megohms or below 2 megohms indicates that each of the three phase cables will need to be tested individually. The tests will determine if one of the cables is faulted to ground or if a blower motor winding is faulted to ground. Proceed to Step “G”.
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Grid blower motor connection enclosure
(12) Three phase cables that are used to supply AC power to the grid blower motor from the RGBI
(13) Three phase cables that go out to the grid blower motor
Remove the cover from lower connection enclosure on the front of the grid assembly. Disconnect the three phase cables (12) that are used to supply AC power to the grid blower motor from the RGBI. Position the cable ends where contact with each other or with the frame cannot occur. If necessary, insulate the