Inspection methods for rotor insulation
- Inspection method after shutdown: Use a 1000-volt multimeter to test the insulation between the rotor and the ground. When the insulation resistance is lower than 2 MΩ, it should be dealt with.
- Inspection method during operation: During operation of the generator, measure through the on-line rotor insulation monitoring device. When there is voltage between the positive or negative pole of the rotor and the ground, it is considered that the rotor insulation resistance has decreased, and the higher the ground voltage, the greater the decrease in insulation resistance. In such cases, the generator should be shut down for handling.
Methods for handling decreased insulation resistance
- If the rotor insulation resistance decreases due to moisture, we use the DC welding machine drying method or short-circuit the three phases of the generator stator to use self-generated heat for drying.
2. If the rotor coil insulation ages, then adopt the method of removing the guard ring, disassemble the rotor for major repair.
3. If the rotor coil end is covered with dust or oil, the common treatment methods are:
3.1 Use dry compressed air for blowing.
3.2 Remove the guard ring, clean the oil, dust, and carbon powder at the end of the rotor coil, and then reprocess the insulation at the end. This method is complex in process and long in duration, which directly affects the economic benefits of the generator.
3.3 Use the electrical equipment cleaning agent to treat the rotor insulation. The author focuses on introducing this method.
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Post time: Mar-09-2026