the Maintenance & Protection of Three-phase Asynchronous Motor

21 Dec 2021174

1 Three-phase asynchronous motor composition and its fault overview

      The faults of three-phase asynchronous motors are mainly divided into electrical faults and mechanical faults. Electrical faults mainly include various switches, fuses, brushes, stator windings, rotors and other equipment faults; mechanical faults mainly include bearings, casing, Failure of parts on equipment such as end caps and rotating shafts.

      The composition of a three-phase asynchronous motor mainly includes two parts, namely a stator and a rotor, and the stator is composed of a stator winding and an iron core, and the stator winding is the core part of the whole three-phase asynchronous motor. From the perspective of the types of faults in three-phase asynchronous motors, most of the faults mainly appear on the windings, such as loss of insulation, poor contact, ground faults, short circuits, and open circuits. In the fault diagnosis and troubleshooting, the motor must first be fully inspected, and the correct fault location must be found using a reasonable diagnosis method, and then the cause of the fault must be judged, and then the fault must be eliminated.

2 Three-phase asynchronous motor fault diagnosis and maintenance methods

2.1 Inspection and maintenance for the inability of the motor to run after it is energized

      In view of the problem that the motor cannot start running after being energized, after analyzing the cause of the fault, we concluded that one is related to insufficient power of the motor, and the other is related to damaged parts. Therefore, when diagnosing faults, you can start from these two aspects. First, check the wires to ensure that the wires can supply power to the motor. Generally, current detection methods are used to detect whether there are current traces inside the motor. If there is no current trace, it means that the wire line appears. Problem.

2.2 Inspection and maintenance for excessive motor running noise

      For the overhaul of excessive noise generated by the motor during operation, the main cause of the failure is related to the aging of internal parts, which increases the running friction. It may also be mixed with foreign objects during operation. Therefore, check from these two Start from the angle, check out the problem in time, and take targeted measures to solve it, so as to avoid the excessive noise problem causing damage to the motor itself, or even harming the surrounding environment and causing huge losses.

2.3 Inspection and maintenance for excessive vibration during motor operation

      For the inspection and diagnosis of large-scale vibration problems during operation, because the vibration problems can be directly seen by the naked eye, the subjective inspection method can be directly used to inspect the vibration parts of the machine, which may only be related to the movement of the machine for a short distance. . It may also be related to the problem of the stator and rotor working trajectory, or foreign matter has been mixed in the motor operation. At this time, it is necessary to use instrument inspection and testing to determine the specific location and cause of the vibration, and then take targeted elimination methods.

2.4 Inspection and maintenance for the excessively high operating temperature of the motor

      In view of the problem of excessive heat generated during the operation of the motor, there will generally be special instruments to test and monitor the temperature. This is to avoid excessive temperature and affect the service life of the machine itself. After analyzing the cause of the failure, we found that the excessive temperature is mainly related to the abnormal operation of the stator and rotor. The stator and rotor, which are the main parts of the motor, will generate more heat if the steering is wrong or the speed is too fast during operation. The heat generated by the motor as a whole increases. In the process of inspection and maintenance, each part of the motor must be carefully inspected and tested to find the specific fault location and use targeted solutions to eliminate it.