The motor winding machine is short-circuited due to damage to the motor insulation, and the motor cannot run due to the surge of current. Among them, overvoltage, undervoltage, overload, lack of phase and mechanical damage, etc., may cause short-circuit failure of the motor winding machine. The short circuit of the motor winding machine has two forms: inter-turn and inter-phase.
Long-term overload operation causes loss of insulation function;
Moisture of the motor winding machine leads to grounding fault; the insulation at the ends or between layers of the motor winding machine is not completed or damaged; the insulation breakdown caused by lightning and other surges; metal parts or tiny organisms enter the motor, etc.
(2) Detection method
1. Observation method. Disassemble the motor and check for smoke and burn marks. When a short circuit occurs, the sparks often generated will burn the insulation, and these traces must be the short-circuit fault point.
2. Power-on inspection method. Use a clamp-on ammeter to measure the three-phase current. If the current of one phase exceeds that of the other phases, it indicates that there is a short circuit in this phase.
3. Multimeter or shake meter testing method. Remove the external wiring of the motor winding machine coil, and measure the two ends of the same phase or two phases with the R×10KΩ gear of a multimeter or a shaker. If the reading is zero or very low, it indicates that there is a short circuit between the two phases or the phase motor winding machine. The point of failure.
(3) Treatment and repair methods
1. A short-circuit fault occurred at the end of the motor winding machine. The short-circuit fault point is insulated with insulating materials, then re-winding, dipping, and finally drying.
2. A short circuit occurs in the wire slot. After softening the motor winding machine, find out the short-circuit fault point, perform insulation repair, re-insert the wire trough, soak the insulating varnish, and finally dry it.
3. The phase-to-phase short circuit cannot generally be repaired, and the motor winding machine can only be replaced.