Characteristics and cause analysis of electric motor overload failure

Electric Motor overload fault refers to the three phase induction motor in operation to withstand the current exceeds its design rating, Shandong Langrui Motor is one of the largest electric motor manufacturers in China. We will analyze some characteristics and possible causes of motor overload failure.

1. Overheating: The surface temperature of the electric motor rises abnormally, and even a burning smell may appear.

2. Excessive current: The current exceeds the rated current when the motor is running.

3. Speed drop: The motor speed decreases, and in severe cases, it may stop.

4. Sound and vibration: Low sound and vibration occur when the motor is running.

5. Burnt smell and black smoke: When the motor is severely overloaded, a burnt smell may be diffused around the motor, even accompanied by black smoke.

6. Winding damage: The insulation part of the winding is black and brittle, and in severe cases, the insulation layer is carbonized into powder.

二, Cause analysis:

1. Overload: The actual operating power of the motor exceeds the rated power, resulting in overload.

2. Phase loss operation: One or more phases of the three-phase power supply of the motor are missing, causing unbalanced operation of the motor.

3. Voltage problem: The operating voltage exceeds the rated voltage allowable value, causing the motor winding to heat up.

4. Mechanical failure: If the bearing is damaged or the mechanical jamming causes the motor speed to drop or stagnate.

5. Misoperation during the test process: If the stall test time is too long, or the test equipment capacity is insufficient, the motor winding will overheat.

6. Wiring error: The star-connected motor is incorrectly connected in a triangle connection, or the voltage is too high when testing the motor with different frequency and voltage.

7. Power supply problem: The power supply voltage is too high or too low, causing the winding to heat up.

8. Impact load: The load suddenly increases, causing the motor speed to suddenly decrease.

9. Bearing system failure: The bearing is damaged or the sweeping of the bore stops, causing the motor to overload.

三, Troubleshooting method:

1. Check the load: Confirm whether the motor is correctly selected and matched with the load.

2. Measure the current: Use an ammeter or clamp meter to measure the actual power consumption of the motor and compare it with the rated value on the nameplate.

3. Check the protection device: confirm whether the motor starter protection device is correctly installed and adjusted.

4. Clean the vents: regularly clean the motor surface and vents to remove debris that hinders airflow.

5. Check the motor wiring: ensure that the motor wiring is correct and there are no wiring errors.

6. Check the power supply: ensure that the power supply voltage is stable and within the allowable range.

Through the above characteristics and cause analysis, the motor overload fault can be effectively identified and handled to ensure the safe and stable operation of the motor.

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