Personal Injury or death can result from improper troubleshooting and repair procedures.
The following troubleshooting and repair procedures should only be performed by qualified personnel familiar with his equipment.
If the insulation resistance values are less than recommended values, one of the following drying procedures must be selected. This decision should be based on the following factors:
The following methods can be used for drying a generator:
When servicing or repairing electric power generation-equipment:
The generator set functional test is a simplified test that can be performed in order to determine if the generator is functional. The generator set functional test should be performed on a generator set that is under load.
The generator set functional test determines if the following statements happen:
The generator set functional test consists of the following steps:
Recommended Periodic Insulation Test
Periodically use a megohmmeter to check the insulation resistance of the generator's main stator winding. The frequency of this test is determined by the generator's environment. Previous megohmmeter readings will also determine the frequency of this test.
Test the main stator windings with a megohmmeter in the following situations:
Space heaters must be used whenever the generator set is not under load. Space heaters must also be used whenever salt is present or whenever high humidity is present. Using a space heater in this fashion is the only way to maintain megohmmeter readings above one megohm. Use space heaters only when the generator is not running.
Rotating Rectifier Test
Testing a Brushless Exciter Rotating Rectifier With An Ohmmeter.
If the failure of a rectifier is suspected, use the following procedure.
The ohmmeter should indicate a low resistance when the ohmmeter leads are across the rectifier in one direction. The ohmmeter should indicate a high resistance when the leads are reversed.
If the ohmmeter indicates a low resistance in both directions, the rectifier is shorted. A high resistance in both directions indicates an open rectifier.
Include the following information when a rectifier is being ordered for replacement:
Source: MaintainX (Community Member)