Today, I will briefly introduce the inspection and maintenance knowledge of three-phase asynchronous motor bearings, focusing on how to check bearings and lubrication methods.

I. inspection method of bearing

(1) listening: use a screwdriver or iron bar, insert one end on the machine with bearing, and use the ear at the other end to hear whether there is any special noise. If there is intermittent sound, it indicates that there may be sundries in the bearing; if there is whistling sound, it indicates that the bearing is lack of lubricating oil or the bearing is in friction.

(2) temperature measurement: use mercury thermometer or alcohol thermometer to measure, the surface temperature plus 10 ℃ is about the internal temperature of the bearing; also use the touch of hand to check, if the hand can contact closely for a long time, the temperature should be below 60 ℃. The normal working temperature of the bearing shall not be higher than the ambient temperature by 55 ℃, and its own temperature shall not be higher than 95 ℃. If it works under excessive temperature, its service life will be reduced or even burnt.

II. Bearing lubrication

(1) adding cycle of lubricating grease

The lubricating grease of the bearing must be kept clean and sufficient. For the motor of sliding bearing, the lubricating oil shall be replaced after 1000 hours of operation; for the motor of rolling bearing, the lubricating grease shall be replaced after 2500-3000 hours of operation, and the lubricating grease shall be added every 1000 hours or so

(2) selection of lubricating grease for rolling bearing

In general, lithium grease is preferred when the working temperature is below 120 ℃, composite soap based or polyurea based grease is used when the temperature is above 120 ℃, and calcium based grease is used in humid environment and water.

(3) add standard of rolling bearing grease

The standard of adding lubricating grease for rolling bearing is determined according to the rotating speed. When the rotating speed is below 1500 rpm, the adding amount is 2 / 3 of the bearing cavity.

The above is how to repair and maintain the three-phase asynchronous motor bearing method, I hope to help you.