Judgment and Maintenance of Common Faults of Three-phase Asynchronous Motor

Judgment and Maintenance of Common Faults of Three-phase Asynchronous Motor
1. Fault phenomena
The vibration of motor is larger in operation
2. Fault Judgment
Because of wear bearing clearance is too large;
(2) Non-uniform air gap;
(3) Rotor unbalance;
(4) Rotating shaft bending;
_Core deformation or loosening;
_The center of coupling (pulley) is not corrected;
The fan is unbalanced;
_Insufficient strength of shell or foundation;
_The foot screw of the motor is loose;
_Cage rotor open welding break; winding rotor open circuit; plus stator winding fault.
3. Troubleshooting
Maintenance of bearings and replacement if necessary;
(2) Adjusting air gap to make it uniform;
(3) Correction of rotor dynamic balance;
(4) Straightening the rotating shaft;
(5) Correction of overlapping cores.
(5) Re-calibration to make it conform to the regulations;
_Maintain the fan, correct the balance and correct its geometric shape;
_Reinforcement;
Tighten the foot screw;
_Repair the rotor winding; Repair the stator winding.
Section 10
1. Fault phenomena
Bearing overheating
2. Fault Judgment
2.1 Too much or too little lipid;
2.2 Oil quality is not good and contains impurities.
2.3 Inappropriate fit of bearing with journal or end cap (too loose or too tight)
2.4 The bearing bore is eccentric and rubs against the shaft.
2.5 The motor end cap or bearing cap is not installed flat.
2.6 The coupling between motor and load is not corrected or the belt is too tight.
2.7 Bearing clearance is too large or too small;
2.8 Motor shaft bending.
3. Troubleshooting
3.1 Add grease (1/3-2/3 of volume) as required.
3.2 Replace clean grease;
3.3 Over-looseness can be repaired with binder, over-tightening, grinding the inner hole of journal or end cover to make it suitable;
3.4 Repair bearing cover to eliminate friction points.
3.5 reassembly;
3.6 Recalibrate and adjust belt tension.
3.7 Replacement of new bearings;
3.8 Correction of motor shaft or replacement of rotor.
Section 11
1. Fault phenomena
Motor overheating or even smoking
2. Fault Judgment
2.1 The overvoltage of the power supply greatly increases the heating of the iron core.
2.2 The power supply voltage is too low, the motor runs with rated load, and the excessive current makes the winding heated.
2.3 When repairing and dismantling windings, the hot dismantling method is improper and the iron core is burned.
2.4 The stator and rotor cores are rubbed together.
2.5 Motor overload or frequent start;
2.6 cage rotor broken bars;
2.7 The motor is out of phase and operates in two phases.
2.8 After rewinding, the winding is not dipped sufficiently.
2.9 The surface of motor with high ambient temperature is dirty, or the ventilation duct is blocked.
2.10 Motor fan fault, poor ventilation; stator winding fault (inter-phase and inter-turn short circuit; stator winding internal connection error)
3. Troubleshooting
3.1 Reduce the power supply voltage (e.g. adjust the tap of power supply transformer). If the error of Y and_connection method of motor is caused, the connection method should be corrected.
3.2 Raise the supply voltage or change the thick supply wire;
3.3 Maintenance of iron core and troubleshooting;
3.4 Eliminate friction points (adjust air gap or setback, car rotor);
3.5 Load reduction; Start according to the specified number of times;
3.6 Check and eliminate rotor winding faults;
3.7 Restore three-phase operation;
3.8 Secondary dipping and vacuum dipping were used.
3.9 Cleaning motor, improving environment temperature, adopting cooling measures
3.10 Inspect and repair fans, replace them if necessary, and repair stator windings to eliminate faults.