Ac motor maintenance:
Preparation and inspection before starting
1. Check whether the grounding of the 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 power supply voltage and frequency.
3. The relative phase and insulation resistance of windings should be checked before starting the newly installed or long-stopped motor. The insulation group shall be larger than 0.5 megohm, if lower than this value, the winding 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 rotating flexibly and whether the oil in the sliding bearing reaches the specified oil level.
6. Check whether the rated current of the fuse used by the motor meets the requirements.
7. Check whether the fastening bolts and mounting bolts of the motor are tightened.
The ac motor can be started after all the above inspections meet the requirements. After the motor is started, it shall run for about 30 minutes without load. Please pay attention to whether there is any abnormal phenomenon of the motor, such as noise, vibration, heating and other abnormal conditions. Measures shall be taken.
When starting the wound motor, the starting rheostat should be connected to the rotor circuit. For the motor with brush lifting mechanism, put down the brush, disconnect the short-circuit device, close the stator circuit switch and switch the rheostat. When the motor is close to the rated speed, lift the brush, close the short circuit device, the motor starts.
