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Causes of Common Faults of AC Motors

Update:08-11-2019
Summary:

As described in the previous article, AC Washer Motor a […]

As described in the previous article, AC Washer Motor are inevitably malfunctioning due to friction, vibration, insulation aging, etc. So we should check it regularly:

1. Listen to the sound, carefully find the fault point AC asynchronous motor is running, if you find a thin "beep" sound, there is no change in height, it is a normal sound, if the sound is thick and sharp sound are precursors to failures and should be considered for the following reasons:

2. Using the sense of smell, the fault motor is odor-free in normal operation. If it smells different, it is a fault signal, such as burnt smell, which is caused by the insulation of the barbecue, and with the increase of the temperature of the AC motor, when it is serious It also emits smoke; if it is oily, it is mostly the lack of oil in the bearing, and the odor of oil and gas evaporates when it is close to the dry grinding state.

3. Using the feel, check the fault, touch the outer casing of the TV by hand, you can roughly judge the temperature. If you touch the motor casing with your hand, you will feel very hot. The temperature value is very high. Check the cause, such as excessive load and voltage. Higher, then troubleshoot for the cause.

Causes of common faults

1.The AC motor does not have a starting torque, or it cannot start when it is empty, and an abnormal sound is emitted.

The reasons are as follows:

(l) The three-phase power supply circuit (including the knife switch and the lead stator winding) has a phase disconnection, resulting in single-phase start.

(2) The power supply voltage is too low.

(3) The bearing is excessively worn, so that the rotor is close to one side of the stator, causing the stator and the rotor to be different, and the air gap is not uniform.

2. The starting torque of the motor is small, it can't be started when there is load, and the motor stops when the load increases, sometimes it emits strong noise and local heat. Reason: The grid voltage is low, the winding has a turn-to-turn short circuit, and there is a disconnection or de-soldering phenomenon in the rotor winding. After the start-up, the one-phase disconnection causes single-phase operation.

3. The starting current is large, and it is unbalanced, and the sound is loud, causing the protection device to operate and cut off the power. Cause: The stator winding wiring method may be incorrect, and the winding insulation is aging to ground.