High voltage motor test standards and procedures

High voltage motor test standards and procedures

The testing standards and procedures for high-voltage motors mainly include core items such as insulation resistance testing, DC resistance testing, and withstand voltage testing. The specific standards are as follows:

1、 Insulation resistance test
Measurement requirements
For motors below 1000V, a 1000V/500V meter should be used. For motors below 3000V, the insulation resistance should be ≥ 0.5M Ω. For motors above 3000V, the absorption ratio (≥ 1.2) should be measured.
The neutral point of the motor needs to be short circuited to the non tested phase ground. If it is not led out, the three-phase should be short circuited and measured.
measuring method
Use a megohmmeter (2500V meter) to connect the main ground to the casing (or neutral point), connect the L end to the winding, and maintain stable speed to read the value.

2、 DC resistance test
Measurement requirements
Motors with a voltage of 3000V or above or a power of 45kW or above, with a phase to phase resistance difference of ≤ 2% of the minimum value; The resistance difference between the neutral point and the motor wires is ≤ 1%.
During measurement, the winding and cable connection should be kept open, the rotor should be stationary, and a thermometer should be placed on the iron core.
measuring method
Use a double arm bridge or direct resistance meter, connect C1/C2 to the winding terminals, and charge the B key to obtain a stable reading.

3、 Voltage withstand test
testing voltage
When replacing the new winding, it is 3Un, and when undergoing major repairs or partial replacements, it is 2.5Un.
The test voltage is gradually increased to the specified value (such as 1.5Un/2Un) for 1 minute, and the leakage current is ≤ 20 μ A.
Experimental steps
Disconnect the neutral point connection, ground the casing, gradually apply pressure, and monitor changes in insulation resistance.

4、 Other key requirements
Environment and safety: Before testing, the motor surface needs to be cleaned to ensure reliable grounding and equipment calibration.
Data recording: Comparing historical data, the change in resistance value should be ≤ 5%, and the temperature rise should comply with the design specifications.

The above standards integrate international (such as IEC 60034-1, IEC 60034-2) and domestic (such as GB/T470-1997) specifications to ensure that the insulation and electrical performance of the motor meet safety requirements.