Multimeter to judge the motor good or bad method
There are three-phase motors and single-phase motors, and single-phase motors come in three-wire and six-wire versions.
Three-phase motors
Three-phase motors have 6 taps on the three-phase winding. We start by removing the connecting tabs that connect the motor terminals. Measure the first and last ends of each phase of the windings with a multimeter in the on-off position to see if they are on or off. Then use a multimeter to measure the resistance between each two-phase winding, at least greater than 0.5 megohm, the larger the better. Finally, then measure the insulation resistance of each phase of the winding and motor shell, should also be infinity. This measurement down basically can judge the three-phase motor good or bad.
Single-phase motor with three wires
A single-phase motor has only two windings, a start winding and a run winding. One of the three wires is their common wire, which is the end of the two-phase winding that is connected together. The other two are the other taps of the two phase windings.
The resistance between the two taps should be maximum and equal to the sum of the resistance values of the two windings.
Of course we also have to measure the resistance of the coil to the chassis to see if it has been penetrated, the higher the resistance the better of course, and the same for the minimum, not less than 0.5 megohm.
Single-phase motor with 6 wires
The reason why there are 6 wires, in fact, there are two wires (Z1, Z2) is the centrifugal switch wire. This motor it also has 6 terminals, so remove its connecting tabs as well. Remove the capacitor as well, and then measure the resistance at the first and last ends of the two phase windings, and between the two phase windings. The method is the same as for a three-phase motor.
Use a multimeter to judge the motor is good or bad, can only be a preliminary judgement, the winding and the insulation resistance between the winding and each phase of the winding to ground insulation resistance, should use megohmmeter to measure to be more accurate.
There is also a short circuit between the turns of the winding is not measured, we can only use the method of comparison to guess, whether there is a short circuit between the turns of the phenomenon. For example, a phase of the winding organisation relative to the other two phases is much smaller, then we can suspect that he has a short circuit between turns.
