The bearing is the most fragile part when a small or a medium-sized electric motor is running. If the bearing is damaged, circses as followed will happen: the increasing of the noise and the vibration, the rising of the working temperature, the decline of the matched equipments’precision, and it may even lead to the burning of the electric motors. So in order to extend the useful life by maintaining the bearings of electric motors, pay attention to the following factors in the course of the installing and using of motors:

1. The installing of the coupling

When the motors are connected to the matched equipments by couplings, the breakage of the bearing caused by the axial force generated by the installing of the coupling should be avoided. Regarding interference fit size, suggest adopting shrink fit or stand up to the side surface of non-driving end to install. This will help to effectively prevent the bearings from the larger axial force, and protect bearings

2. Lubrication for bearing 

A current research about the bearings-broken found that 36 persent of the cases caused by the bad lubrication for bearing or failed to apply the lubricant. Changing bearings is a tremendous hard work and many problems caused by bearings working too long. So it is the time to apply lubricant to bearings when electric motor continuously working for 6 months in normal circumstances.

Attentions:

A. the colour of lubricant turns dark 

B. covered by beads and dust

C. the lubricant becoming hard and going bad

D. the temperature of the bearing above 95℃

In all above conditions means the lubricant must be changed immediately. Changing steps shown below:

- clear up the lubricant presently, and wash the bearings and bearing cap

- apply new lubricant to the bearings(It is better that 2/3 of the bearing house is filled with lubricant )

3. Contaminated lubricant

Bearings are so delicacy that failure to work will caused by contaminated lubricant. For this reason, the running environment of the electric motors have to conform to the requirement of protection class.（See IEC 60034-5 for the specific requirements）

4、Fatigue 

   The corollary equipment, overloading and maintained in unsuitable measures will damage the bearing. A research found that primary reason of bearings earlier broken is fatigued. And 34% of the cases of earlier broken are caused by this reason. For this reason, electric motors must run in the rated conditions and avoid overloading.