How to analyze and diagnose the fault of asynchronous motor

1. When the equipment fails, you must first investigate the situation.

Inquire the operator about the operation situation before and after the motor failure and the process and phenomenon of the fault; then observe the fault scene to see if there is any obvious damage or abnormal smell on the surface of the equipment; then turn the rotating part by hand to check whether it is flexible or Looseness, noise, etc., can initially understand the degree of damage inside the motor and the fault location.

When the above inspection does not find a big problem, measure the power supply voltage and check its insulation, such as the DC resistance of the motor winding and the grounding insulation resistance. Check the starting equipment of the motor and some electrical equipment of the control circuit. Check the motor winding lead-out wiring and cable wiring for faults. Disconnect the motor from the mechanical connection, turn the motor to no-load, and check the motor body for faults. When no-load test is carried out, carefully observe the sound, odor, vibration, temperature rise, current, voltage and speed; and make a correct judgment according to the actual situation.

2. Method for detecting motor failure

Visual inspection, through the eyes, ears, nose, hand touch to find faults. Check whether the outer surface is burnt, deformed, etc., whether the nose smells the device for abnormal smell, listen to the running sound of the motor, whether there is abnormal noise, whether there is vibration or the like. Intuitive and unpredictable, it can be detected by instrument: the multi-meter can be used to measure the power supply voltage; the double-arm bridge is used to measure whether the device has abnormal odor winding DC resistance; the insulation resistance meter measures the motor winding to ground insulation; the clamp-type ammeter measures the three-phase current. Whether it is balanced.