Squirrel Cage Motor

Common causes: power phase loss, motor winding short circuit to ground or between turns, thermal relay set current too low, excessive starting load or mechanical jamming. First power off and measure insulation and DC resistance, then check mechanical rotation and the thermal relay setting.

First verify the sensor range, check for loose wiring and whether the probe is properly attached to the measuring point, then compare data from other measuring points at the same position. If it is confirmed as sensor drift or false alarm, replace the sensor to avoid long-term protection bypass causing accidents.

Check whether the control power fuse/circuit breaker has tripped, the emergency stop button is reset, the safety door limit switches and interlock circuits are closed, and the contactor coil is energized. Measure voltage section by section per the drawing to locate the fault.