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AC motor bearing disassembly and replacement
Jul 24, 2018

Motor bearings, also known as motor bearings or motor bearings, are special bearings for motors or motors. The motor bearing used in the motor is a part that supports the shaft. It can guide the rotation of the shaft and can also withstand the components that are idle on the shaft. The concept of the bearing is very broad. There are four types of bearings commonly used in motors, namely rolling bearings, plain bearings, joint bearings and oil-impregnated bearings. The most common motor bearings are rolling bearings, ie bearings with rolling elements. A plain bearing refers to a bearing that has no rolling elements, that is, a bearing that performs a sliding motion.

The bearing is a part that supports the shaft. It can guide the rotation of the shaft and can also withstand the components that are idle on the shaft. The concept of the bearing is very broad. There are four types of bearings commonly used in motors, namely rolling bearings, plain bearings, joint bearings and oil-impregnated bearings. The most common motor bearings are rolling bearings, ie bearings with rolling elements. A plain bearing refers to a bearing that has no rolling elements, that is, a bearing that performs a sliding motion.

According to HG25103-91 "equipment maintenance and repair regulations", the motor bearing temperature should not exceed 95 °C, the requirements of the second-class motor is not more than 90 degrees, and when the current is not exceeded, the temperature does not exceed 40 degrees. The status is OK.

If the three-phase asynchronous AC motor needs to be disassembled for some reason (such as cleaning or repairing the rotor or stator), then the grease in the bearing and bearing cap can be cleaned with grease solvent. Then, fill the bearing with approximately 50% of the space with grease or similar grease recommended by the motor manufacturer. But be sure to keep the grease clean. Because the gap between the ball bearing and the roller bearing is small. Heavy-duty ball bearings, when the ball and the race are in contact, the compressive stress is usually around 7000 MPa in the contact area per minute. Therefore, it can be seen that a small piece of hard sand or cast iron dust may damage the ball or the seat.

When installing a new bearing, first confirm its specifications and the type is correct. In most cases, the bearing type is marked on the motor nameplate or on the bearing end cover. If it is not possible to purchase the original bearing, it is best to check with the manufacturer to use a suitable replacement bearing. Prior to installation, all machined surfaces are cleaned with a suitable solvent and the machined mating surfaces of the end caps, housings, oil retaining ring and grease cap are checked for burrs. Whether these mating surfaces are smooth or not is of great significance.

If a bearing of an AC motor is not disassembled, care must be taken when disassembling the bearing and installing the bearing or replacing the new bearing, and be aware that the bearing detacher should be used. When possible, apply tension on the inner ring. Pulling the outer ring will affect the bearing steel ball, which may deform the surface of the bearing steel ball. If the outer ring is not pulled, replace the bearing. Unless new bearings of the same specification cannot be purchased, in fact, the bearings that are pulled down should generally be replaced.


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