Causes of motor bearing heating and experience in replenishing and replacing grease
Date：2024-03-26 Author：XINDA MOTOR
The high temperature of motor bearings is mainly due to the following reasons
1. The grease brand is inappropriate.
2. The grease is of poor quality or has deteriorated.
3. There is too much or too little grease in the bearing cavity.
4. There are impurities in the grease.
5. The bearing runs on the outer ring or inner ring.
6. The bearing model is incorrect or of poor quality.
7. The coupling is misaligned.
8. The belt is pulled too tight.
9. The motor vibrates too much.
2. When replacing the grease, remove the old grease, clean the bearings and bearing caps, and then add new grease. The amount of grease added should be 1/2-2/3 of the bearing cavity space (for a 2-pole motor) The amount of grease is 1/2 of the cavity, and the amount of grease for 4-pole, 6-pole and 8-pole motor bearings is 2/3 of the cavity). If there is too much or too little grease, it will cause the bearing to heat up during operation, causing the grease to decompose and deteriorate.
3. The motor in use should be refueled regularly. If there is a time requirement on the nameplate of the motor housing, please refuel regularly as required. If there is no time requirement on the nameplate, please refuel regularly as required in the motor manual. Motor bearings usually need to be replenished with oil to run for 2000 to 3000 hours, and the amount of replenished oil is 20 to 50 grams. When the equipment is running under high load, the refueling frequency can be appropriately increased. If the equipment is not used for a long time, the refueling amount does not need to be that much, just a little replenishment is enough.
4. The motor bearing oil needs to be replenished during operation. When replenishing oil, the oil nozzle needs to be wiped clean. Do not add too much oil at one time, otherwise the bearing will easily heat up, and the increased revenue will not be worth the loss. You can add a little first and observe whether the bearing temperature, sound, etc. change, and then add again. After adding oil, the sound and vibration of the bearing should change, so pay attention to observation.
5. For high-voltage motors and some high-power low-voltage motors, there is an oil drain hole under the bearing cover for draining excess oil in the bearing and waste oil that has been emulsified and deteriorated after use. In principle, it needs to be drained regularly. It is recommended to clean the waste oil from the oil drain hole before and after oil filling.
6. In dusty, humid, and high-temperature environments, grease should be replaced frequently. When replacing bearings, clean them with kerosene and gasoline before injecting grease. After the bearings are filled with lubricating oil, the motor rotor should be easily pulled by hand.
7. Motor bearings have limited service life. Under normal oil replenishment and oil change conditions, when the motor bearing generates heat or abnormal noise, you should consider whether the motor bearing has reached the end of its service life. It is recommended that the bearings of normally operating motors be replaced every three years. For high-load motors or motors where dust is easy to enter the bearings, this time should be shortened, and it is recommended that the bearings be replaced once a year.
8. The bearings used in motors without oiling holes (usually low-power motors) are sealed bearings. During the service life, there is no need to replace the bearings with grease, and the bearings can be replaced according to the time of replacing the motor bearings.
The oil replenishment and oil change of the motor bearings should be handled correctly according to the on-site usage conditions. It is not static, and problems must be checked frequently and dealt with promptly to keep the motor in good operating condition.
XINDA