Bearings are key components that support the normal operation of motors. The design and configuration of high speed motor bearings is very important. For example, horizontal and vertical of high speed motors should use different bearing configurations. Motors with different speed requirements should also use different bearings. Here, China Simo Motor Engineers provides you some suggests.
1 Configuration of horizontal motor bearings
A ball bearing and a column bearing should be used at both ends of the horizontal motor as much as possible. At present, domestic 2-pole small and medium-sized motors mostly use two ball bearings, although some manufacturers have made some adjustments to the tolerance of the bearing inner diameter to the direction of clearance fit, in order to alleviate the problem of ball squeezing after the bearing heats up. However, since the expansion coefficient of the bearing jacket is larger than that of the end cover or bearing sleeve, the cast iron part that houses the bearing chamber, and the temperature at the bearing jacket is also higher, the bearing jacket can originally move axially in the bearing chamber at room temperature. It slides a little, but the bearing may not be able to move in series after being heated during operation. This is the main reason why the bearing life is short and easy to heat up when using two ball bearings. After the temperature rise test of a motor using two ball bearings, the motor is stopped to measure the temperature rise. Sometimes the bearings of the motor are burned out when the motor is started for the second time. The reason is that the clearance of the ball bearings cannot bear the thermal expansion and contraction of the rotor, and the jacket It cannot creep in the bearing chamber, causing the balls to bear a large axial force.
If you choose a ball bearing and a column bearing, the above problems can be avoided. A better motor factory in the same company changed the 2-pole high-voltage motor in the H560 frame size from two ball bearings to one ball bearing and one column bearing, and the later operating results were very good. Except for replacing the bearings according to the regular maintenance cycle, there has never been a failure during normal operation. And the temperature measured at the bearing was only 20°C. This is the first successful case in China where the traditional use of two ball bearings in a 2-pole high speed motor was changed to one ball bearing and one column bearing. It has now been gradually promoted in explosion-proof motors.
In order to solve the problem of extreme speed heating and noise after using column bearings instead of ball bearings, light series column bearings can be used and placed at the outer fan end. The cooling condition is good, and the bearing noise can also be drowned by the fan noise. If a larger power 2-pole motor uses a larger bearing model and the light series column bearing is unable to meet the limit speed requirements, the bearing grease can also be changed to thin oil.
China Simo Motor is professional in producing electric motors including high speed motor. Welcome to contact with us at sales@simo-motor.com.cn.