How to use a multimeter to judge whether a motor is good or bad

　　The method of using a multimeter to determine whether a single-phase or three-phase motor is burned out is only applicable to small motors with a DC resistance of the coil winding of more than 1 ohm.

　　The method to determine whether a three-phase motor is burned out is relatively simple. Use a multimeter to test whether the DC resistance of the three-phase winding is balanced. If it is unbalanced, it can be determined that the three-phase motor is burned out.

　　The DC resistance of the starting winding of a two-phase motor is generally greater than that of the running winding. The simplest way to determine this is;

　　1. First use a multimeter to measure the DC resistance from the common end to the running winding end and the starting winding end respectively.

　　2. Then use a multimeter to measure the DC resistance from the running winding end to the starting winding end.

　　3. If the arithmetic sum of the two measurements in "1" is not equal to the measured value in "2", then the motor must be burned! If they are equal, it is best to compare with a motor of the same model, or find the factory parameters of the motor for comparison. To judge whether the motor is good or bad, one more thing to add is that the capacitor should be disconnected when measuring a single-phase motor. If a single-phase motor is short-circuited, you need to have a normal resistance value as a reference. It is simple to use the two methods of smell and observation.