How to repair the motor?
(1) External observation method. Observe whether the junction box and the winding end are burnt. After the windings overheat, leave a dark brown color and smell.
(2) Temperature inspection method. No-load operation for 20 minutes (stop immediately when abnormality is found), touch the windings to check if the parts exceed the normal temperature.
(3) electricity test method. With ammeter measurement, if the current of a phase is too large, there is a short circuit in the phase.
(4) Bridge inspection. Measure the winding DC resistance, the general phase difference should not exceed 5% or more, if exceeds, then the resistance has a short circuit fault.
(5) Short-circuit detector method. If there is a short circuit in the measured winding, the steel plate will vibrate.
(6) Multimeter or Megohmmeter method. Measure the insulation resistance between any two phase windings. If the reading is very small or zero, it means that there is a short circuit between the two phases.
(7) Voltage drop method. After the three windings are connected in series, they are connected to low-voltage safe alternating current.
(8) Current method. When the motor runs at no load, the three-phase current is measured first, and the two-phase measurement is replaced and compared. If the change does not change with the power supply, the one-phase winding with a large current has a short circuit.