Triple-phase asynchronous motor maintenance

Preparation and inspection before startup

1. Check whether the grounding of electric and starting equipment is reliable and complete, and whether the wiring is correct and good.

2. Check whether the voltage and frequency shown on the motor nameplate are consistent with the voltage and frequency of the power supply.

3. Before starting the newly installed or long-used motor, check the winding relative phase and relative insulation resistance.The insulated group shall be greater than 0.5 megohm. If the value is lower than this, the windings shall be dried.

4. For the wound rotor, check whether the brush device on the collector ring can work normally and whether the brush pressure meets the requirements.

5. Check whether the motor is flexible in rotation and whether the oil in the sliding bearing reaches the specified oil level.

6. Check whether the rated current of the fuse used in the motor meets the requirements.

7. Check whether the tightening bolts and mounting bolts of the motor are tightened.

After all the above inspections meet the requirements, the motor can be started.After the motor is started, it should run for about 30 minutes without load. Pay attention to observe whether there are abnormal phenomena in the motor. If abnormal conditions such as noise, vibration and heat are found, measures should be taken.

When starting a wound motor, the starting rheostat should be connected into the rotor circuit.For motors with brush lifting mechanism, put down the brush, disconnect the short-circuit device, close the stator circuit switch and pull the rheostat.When the motor is close to the rated speed, lift the brush, close the short-circuit device, and the motor is started.

Maintenance in operation

1. The motor should always be kept clean and no sundries are allowed to enter the motor;Air inlet and outlet must be kept clear.

2. Monitor the power supply voltage, frequency and load current of the motor with instruments.The voltage and frequency of the power supply shall conform to the motor nameplate data, and the load current of the motor shall not exceed the specified value on the nameplate; otherwise, the cause shall be found out, measures shall be taken, and the operation shall continue until the bad conditions are eliminated.

3. Take necessary measures to detect the temperature rise of each part of the motor.

4. For the wound rotor motor, always pay attention to the contact pressure, wear and spark between brush and collector ring.When the motor stops, the switch in the stator circuit should be disconnected, and then the brush lifting mechanism should be pulled to the starting position to disconnect the short-circuit device.

5. Regular maintenance of the motor after operation, generally divided into minor repair and major repair.Minor repair is a general overhaul. No major disassembly is required for the motor starting equipment and the whole. It is about once a quarter.