How to analysis problems of motor bearing

The cause of the problem of lack of oil in the bearing is the loss of grease or the deterioration of the grease due to the motor running too long.


 Too much fuel or too thick oil, dirty oil, mixed with particulate impurities.

● The shaft is flexed, the transmission assembly is not correct and the eccentricity is caused, the transmission belt or the coupling is too tight, etc., causing the bearing to suffer extra unbalance bending torque and increased friction loss.

End cap or bearing installation accuracy is not high, with too tight or too loose;

● Flange cover the pelvic structure and equipment to form a closed space, the bearing device sealed up, the friction heat can not get out, continue to accumulate, resulting in bearing overheating.

The vibration during the operation of the motor is inevitable, the grease in the bearing may be lost, so that the bearing dry grinding fever until overheating burned.


● Influence of shaft current. Due to the sometimes unbalanced stator field of a large motor, an induced electromotive force is generated on the shaft. The imbalance of the magnetic field may be caused by local corrosion of the iron core, increased resistance, and uneven air gap between the stator and the rotor, which may cause shaft current to generate eddy current.


In order to prevent the motor bearing eddy current, the bearing pad at the end of the motor under the padded insulation board at the same time to the bearing seat bolts, pins, tubing and flange insulation plate sets to cut off eddy current path. The best way to solve this problem is to adopt the system of insulated bearing system, the forum will be opened on the issue and exchange.

Bearing corrosion

Motor running condition bearing corrosion failure is relatively small. Generally due to the bearing cap bolts are not in place, causing the motor water in operation, caused by the failure of lubricants. Long-term motor does not run, because of the continued erosion of moisture will rust.

Cage loose

Cage easily lead to loose in the operation of the cage and the rolling body collision, wear and tear, severe cage rivets will rupture, deterioration of lubrication conditions, leading to bearing lock.


The new bearing cage material, product accuracy, assembly accuracy and other defects is the main cause of cage failure.

Bearing rolling body fatigue stripping

Rolling bearing fatigue for many reasons, the bearing inner and outer ring raceway defects, bearing clearance is too large, bearing overuse, the bearing itself defects in materials and so will lead to the rolling body peel.


Bearings in the course of long-term use of the high load, high speed state is one of the important reasons for bearing fatigue. Rolling elements in the bearing, outer ring raceway constantly rotating, sliding, raceway itself, the defect of the raceway surface uneven, too large clearance to the rolling body in motion to withstand high-frequency, high-intensity impact load, coupled with Bearings of the material defects as well as the use of bearings overrun will cause the bearing rolling body fatigue stripping.