Methods to avoid aging of three-phase asynchronous motor

Release time：2020-05-08 15:36Number of views：Originate：

As a common power output device in mechanical equipment, the aging of three-phase asynchronous motor will produce many problems, which are generally manifested in the increase of motor heat output, the decrease of motor efficiency and the increase of motor running current. However, as long as the daily maintenance is proper, the aging of the motor will be delayed, and the service life of the three-phase asynchronous motor will be effectively extended. The three-phase asynchronous motor factory will teach you how to prevent the aging failure of the three-phase asynchronous motor.

 

There are several types of aging of three-phase asynchronous motor: motor insulation aging and motor mechanical aging.

 

Aging of motor insulation will cause electrical failure. Abnormal insulation between motor phases or to ground will result in turn to turn short circuit or motor phase loss operation, or rotor bar break will result in insufficient motor output and motor over-current.

 

The mechanical aging of the motor will lead to failure, such as motor hole cleaning, bearing overheating, excessive vibration, abnormal sound, etc. As long as these faults are found and handled in time, the motor will not be damaged generally.

 

Whether the motor is mechanical aging or insulation aging, it will not immediately damage the motor. Motor current, front and rear bearing temperature, motor body temperature, motor running current balance, motor vibration and other parameters. Will give some feedback.

 

The regular inspection and maintenance of the motor is very important. If the operation parameters of the motor are checked and recorded every day, if any abnormal parameters are found during the inspection, the motor can be better protected.

 

The regular maintenance work is roughly as follows: the front and rear end bearings of the motor need to be regularly filled with grease, the motor vents need to be regularly cleaned, the motor terminals need to be regularly tightened, and the motor coil insulation, operating current and load need to be regularly checked.

 

The motor consists of enameled wires for fans and transformers. If the aging can be seen from the outside and the paint package turns dark brown, the aging degree of the motor can be determined by comparing the decomposed and burned black carbon coils. This is a sign that the motor is different from the old one. In general, the motor load is heavy and hot, which easily leads to aging of insulating paper. The paint coating is affected by humid air and electric leakage. The magnetic flux of aging silicon steel sheet also decreases, which affects the rotating speed.

 

If you say the motor is aging, it's basically insulated. The bearing is worn and the shell is rusted. After aging, the insulation will be reduced and easy to be damped. Usually, it needs to be dried, or the winding must be rewound, soaked in paint and dried before it can be reused. The result of insulation aging is a short circuit to ground or between phases. We hereby stipulate that the insulation test shall be carried out after the motor has been shut down for more than 72 hours or after major repair (such as replacing the bearing, pumping through the rotor, opening the cover, etc.). When a single motor stops cooling, the insulation to the ground will return to zero. Before reuse, it must be dried to restore the insulation, otherwise it must be repaired.

 

After years of use, the insulation of the motor will age, which will reduce the insulation resistance, increase the possibility of leakage and reduce the safety. The aging insulation between the stator and the rotor's silicon steel sheet will increase the eddy current of the core, which will lead to higher motor temperature, higher power consumption, lower load capacity, higher noise and other problems.

 

Depending on the aging site, the possible faults will vary. If the insulation is aged, there may be ground fault, phase to phase short circuit and other faults. If the enclosure is aged, the sealing performance of the motor may become poor and easy to be damped. If the fixed parts are damaged, the vibration of the motor may be increased and the aging may be accelerated.

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