How to maintain the components of three-phase asynchronous m

Release time：2020-05-08 16:00Number of views：Originate：

Repair of frame and end cover fault

 

The base and end cover of three-phase asynchronous motor are mostly cast iron. Cracks and damage may occur if they are not used, handled and disassembled carefully. Follow the three-phase asynchronous motor manufacturers to see the maintenance methods of other parts of the three-phase asynchronous motor.

 

(1) For the longitudinal or transverse cracks in the stator shell, if the length does not exceed 50% of the corresponding length or width, repair welding can be carried out. For cast iron shell, preheat to about 700 ℃, then use cast iron electrode for hot welding, and use DC welding machine.

 

(2) For cracks in the end cover, hot welding with cast iron electrode can also be used.

 

Repair of rotating shaft fault

 

The rotating shaft of the motor supports the rotation of the rotor core and maintains a proper uniform air gap between the stator and the rotor. Common faults of motor shaft include bending, shaft crack, fracture, journal wear, etc.

 

(1) Bending of rotation axis

 

The bending of the rotating shaft will lead to the loss of dynamic balance of the rotor, and produce greater vibration during operation, which will cause the rotor hole to be cleaned in serious cases. When the motor rotates, the bending of the shaft can be distinguished by observing the runout of the shaft extension end. The shaft that is not bent will not jump. The more serious the bending is, the more serious the jump is. Under normal circumstances, minor bending of the shaft is allowed, but if the bending is more than 0.2 mm, it should be corrected.

 

(2) Broken shaft

 

In this case, a new spindle should usually be replaced. However, if there are only cracks, and the crack depth is not more than 10% - 15% of the journal, and the length is not more than 10% of the shaft length or circumference, the weld overlay can be used for repair.

 

(3) Journal wear

 

The wear of the journal will lead to the displacement of the rotor and increase the abnormal vibration of the motor. In serious cases, it will cause the rotor to sweep through the hole. If the wear is not too serious, the anchor can be plated on the journal. If the wear is serious, it can be repaired by heat sleeve method.

 

Repair of core failure

 

The common faults of iron core include surface damage of iron core, loosening of iron core, overheating of iron core and burning of tooth root.

 

(1) Core surface damage

 

First, deburring, repairing and leveling the silicon steel sheet with flat copper terbium, separating the connected silicon steel sheet, cleaning the surface with gasoline brush, and then applying a layer of insulating paint.

 

(2) Loose core

 

The iron core can be fixed by adding positioning screws on the shell, or it can be firmly welded by electric welding.

 

3) Core overheating

 

This situation is caused by the aging or falling off of the film between the films and the increase of eddy current loss. Whether repair is necessary shall be determined after temperature rise test. When removing the silicon steel sheet, pay attention to the positioning holes and keep the original order. Deburring the silicon steel sheet to be coated with insulating paint, cleaning and drying with gasoline, then coating insulating paint on both sides of the silicon steel sheet, drying and reassembling.

 

(4) Root burned

 

This phenomenon is caused by a ground fault. The burned root can be removed, burred and filled with insulating glue.

Next：Overload symptoms and causes of three-phase asynchronous motor
Last：Three phase asynchronous motor maintenance from these aspect