How to measure the ground resistance of the motor and judge the quality of the multimeter
1. Use the resistance gear to measure the insulation resistance of the casing and the enclosure. It should be above 500K.
2. Use the resistance gear to test whether the three phases are balanced (the resistance values of the three sets of windings are approximately equal).
3. Use the on-off gear of a multimeter to measure the on-off of the two terminals of each group of windings. If it is on, it is good, and if it is off, the circuit is broken; if the different windings are on, then the motor is short-circuited.
4. If it is short-circuited or burned out, use the milliamp current gear to short-circuit any two phases, turn the motor carefully to see what the current is, and then exchange the phase wires to see if it is similar. This method is based on the principle of using the remanence of the old motor to generate electricity , this method is less useful.
