What should be noted when measuring the insulation resistance of Rolling Mill Motor?

1. Power-off operation: Before measuring, be sure to disconnect the power supply of the motor and completely disconnect the motor terminals from the external circuit to ensure that the motor is in a power-free state to ensure personal safety and measurement accuracy.
2. Discharge treatment: After the motor is powered off, the motor winding should be discharged to release any residual charge. Discharge can be performed by short-circuiting the winding terminals. The discharge time should be long enough, usually not less than 5 minutes.
3. Choose a suitable megohmmeter: Select the voltage level of the megohmmeter according to the rated voltage of the motor. Generally speaking, a 500V megohmmeter is used for motors with a rated voltage below 500V; a 1000V megohmmeter is used for motors with a rated voltage of 500-1000V; and a 2500V megohmmeter is used for motors with a rated voltage above 1000V.
4. Measurement environment: The measurement should be performed in a dry environment without strong electromagnetic interference. Avoid measuring in an environment with high humidity, high temperature or low temperature to avoid affecting the measurement results.
5. Correct wiring: Connect the "L" end (line end) of the megohmmeter to the winding terminal of the motor, and the "E" end (ground end) to the motor housing or ground terminal. Make sure the wiring is firm and the contact is good.
6. Shake at a constant speed: When shaking the megohmmeter handle, keep a constant speed, usually about 120 rpm.
7. Measurement time: When reading the insulation resistance value, the megohmmeter should be shaken continuously for 1 minute before reading.
8. Multiple measurements: In order to obtain accurate results, multiple measurements can be performed and the average value is taken as the final insulation resistance value.
9. Recording and analysis: After the measurement is completed, the measurement results should be recorded and compared with the technical requirements of the motor or previous measurement data to determine whether the insulation condition is normal.