Introduction to three-phase asynchronous motor: three-phase asynchronous motor is widely used in industrial and agricultural production and other national economic sectors for its advantages of simplicity, reliability, durability, easy manufacturing, low price and high efficiency. It consists of stator, rotor and air gap. In addition, there are end caps, bearings, stands, fans and other components.
1. The motor has abnormal sound or excessive vibration
Causes: 1. Mechanical friction (including stator and rotor friction), or friction between coupling and motor. 2. The motor is running without phase. 3. The rolling bearing is short of oil or damaged. 4. Motor wiring error. 5. Bent shaft extension or damaged shaft. 6. The coupling is loose, the balance of rotor and pulley is not corrected, and the pulley and coupling are eccentric. 7. The installation foundation is unbalanced or defective.
Corresponding countermeasures: 1. Check the clearance between the rotating part and the static part, find out the cause of the friction, and correct it. When the motor rotor is pulling out the core, the rotor must be lifted to prevent the stator and rotor core from friction with each other. 2. First check the power supply. If the power supply is normal, check the motor and repair it. 3. Clean and check the bearing. If the bearing is damaged, replace the bearing. 4. Find out the cause and correct it. 5. Straighten the shaft or replace the rotor. 6. Find out the looseness, tighten the bolts, and correct the balance and concentricity of the rotor, pulley and coupling. 7. Check foundation and base plate fixing and correct.
2. Motor temperature rise too high or smoke
Possible causes: 1. Heavy load. 2. Phase loss operation. 3. The power supply voltage is too low or the motor is connected incorrectly. 4. Stator winding grounding or turn to turn, phase to phase short circuit. 5. Broken rotor bar of squirrel cage motor. 6. Stator and rotor rub. 7. Poor ventilation. 8. The power frequency does not meet the requirements.
Treatment: 1. Use clamp ammeter to detect the stator current. If overload is found, reduce the load and do not pull the cart. 2. Check the fuse and control grounding point, and remove the fault. 3. Check the power supply voltage and motor wiring. The delta connected motor is wrongly connected to the star working mode or the star connected motor is wrongly connected to the triangle working mode. 4. Find out the ground or short circuit and repair it. 5. Replace and repair the copper strip. 6. Measure the air gap of motor, check the assembly quality and bearing wear, find out the cause and repair. 7. Remove dirt, dust and sundries from the air duct to make the air duct smooth. Ensure that the motor is clean, well ventilated and well cooled, and avoid frequent starting of the motor. 8. Adjust the power frequency to meet the requirements.