Causes and Solutions of Explosion-proof Motor Vibration

1. The hazards of explosion-proof motor vibration

The vibration of the explosion-proof motor will shorten the life of the winding insulation and the bearing, and affect the normal lubrication of the sliding bearing. The vibration force will promote the expansion of the insulation gap, and the external dust and moisture will invade it, resulting in a decrease in insulation resistance and an increase in leakage current, and even accidents such as insulation breakdown.

In addition, the vibration of the explosion proof vfd motor will easily cause the water pipe of the cooler to crack and the welding point to vibrate. At the same time, it will cause damage to the load machinery, reduce the accuracy of the workpiece, cause fatigue of all vibrating mechanical parts, and cause the anchor screws to loosen or broken.

The vibration of the motor will cause abnormal wear of the carbon brushes and slip rings, and even severe brush fire will burn the collector ring insulation, and the motor will generate a lot of noise. This situation generally occurs in DC motors from time to time.

2. The cause of explosion-proof motor vibration

Electromagnetic reasons: 

(1) Power supply: the three-phase voltage is unbalanced, and the three-phase motor runs without a phase. 

(2) Stator: the stator core becomes elliptical, eccentric, and loose; the stator winding has disconnection, grounding breakdown, inter-turn short circuit, wrong wiring, and the three-phase current of the stator is unbalanced. 

(3) Rotor failure: the rotor core becomes elliptical, eccentric and loose. The rotor cage and the end ring are welded open, the rotor cage is broken, the winding is wrong, the brush is in poor contact, etc.

Mechanical reasons: 

(1) In terms of the explosion-proof motor itself, the rotor is unbalanced, the shaft is bent, the slip ring is deformed, the air gap between the stator and the rotor is uneven, the magnetic center of the stator and the rotor is inconsistent, the bearing is faulty, the foundation is poorly installed, the strength of the mechanical mechanism is not enough, resonance, The anchor screws are loose, and the motor fan is damaged. 

(2) In terms of cooperation with the coupling, the coupling is damaged, the coupling is poorly connected, the center of the coupling is not accurate, the load is mechanically unbalanced, and the system resonates, etc. The shaft system of the linkage part is not aligned, the center lines do not coincide, and the centering is not correct. This kind of failure is mainly caused by poor alignment and improper installation during the installation process.

3. The solution to the vibration of the explosion-proof motor

CCS MOTOR power control equipment company suggests that the influence of the surrounding components on the explosion-proof motor should be checked first, and then the coupling should be untied to allow the explosion-proof motor to run idly. If there is no vibration when idling, it means that the vibration is caused by the misalignment of the center line of the explosion-proof motor shaft and the mechanical load shaft, or the failure of the mechanical load. If the explosion-proof motor still vibrates when it is idling, it is caused by the explosion-proof motor itself. The power can be cut off and then judged. If the vibration disappears immediately after the power is cut off, it is electromagnetic vibration, and the fault may be disconnection of the parallel branch of the winding, damage to the bearing, uneven air gap, etc. If it still vibrates after the power is cut off, it is mechanical vibration, such as unbalanced rotor, damaged bearing, etc.