The regulations stipulate that the maximum temperature of rolling bearings should not exceed 95℃, and the maximum temperature of sliding bearings should not exceed 80℃. Furthermore, the temperature rise should not exceed 55℃ (temperature rise is the bearing temperature minus the ambient temperature during testing).
(1) Cause: Shaft bending, centerline inaccurate. Solution: Re-align.
(2) Cause: Loose foundation screws. Solution: Tighten foundation screws.
(3) Cause: Unclean lubricating oil. Solution: Replace lubricating oil.
(4) Cause: Lubricating oil used for too long without replacement. Solution: Clean the bearing and replace the lubricating oil.
(5) Cause: Damaged balls or rollers in the bearing.
Solution: Replace with a new bearing.
According to national standards, for F-class insulation and B-class assessment, the motor temperature rise should be controlled at 80K (resistance method) or 90K (component method). Considering an ambient temperature of 40℃, the maximum operating temperature of the motor should not exceed 120/130℃.
The maximum allowable bearing temperature is 95 degrees Celsius. Using an infrared detector to measure the temperature of the outer surface of the bearing housing, empirically, the highest point temperature of a 4-pole motor should not exceed 70℃. The motor itself does not require monitoring. Once manufactured, the motor's temperature rise is generally constant and will not change abruptly or increase continuously during operation. However, bearings are wear parts and require inspection.