Common causes of bearing damage of the hottest DC

2022-08-07
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Common causes for bearing damage of DC motor

1. there are manufacturing quality problems in the bearing itself, such as rust spots on the raceway, inflexible rotation, excessive clearance, cage deformation, etc

2. the standby machine does not operate for a long time, the grease is deteriorated, the bearing is rusted and no intermediate maintenance is carried out. Because the temperature rise of the motor body is too high and the bearing is not filled with grease in time, the bearing is lack of oil or even burned

3. bearing damage due to mixed use of different types of grease

4. the bearing is replaced and processed again. After the motor end cover is nested, the interference is large or the ovality exceeds the standard, which causes the bearing ball clearance to be too small or uneven, resulting in the increase of the friction force when the bearing is running, and the temperature rises sharply until it is burnt out

5. due to axial dislocation of stator and rotor cores or insufficient accuracy after re machining of the rotating shaft, the inner and outer rings of the bearing are not on the same section, causing the temperature of the bearing to rise after hard operation until it is burnt out; Sharing the single car market situation 10 points considerable

6. the bearing is improperly assembled. If the layer to be worn and the friction paper of the sample unevenly knock on the inner ring of the bearing during cold installation, the shaft will be worn, resulting in the loss of interference between the inner ring of the bearing and the bearing or the reduction of interference, resulting in the phenomenon of running off the inner ring. When the end cover of the electric machine is unevenly knocked, resulting in the loose fit between the end cover bearing chamber and the outer ring of the bearing, resulting in the phenomenon of running off the outer ring. Whether running the inner race or the outer race will cause the temperature rise of the bearing to rise sharply and burn out. In particular, the failure of the inner race will cause serious wear and bending of the shaft. However, intermittent running of the outer ring generally will not cause a sharp rise in bearing temperature. As long as the bearing is in good condition, intermittent running of the outer ring is allowed

7. the bearing cavity is not cleaned or the grease is not clean. For example, shaft tightening: the small rigid materials in the bearing cage, such as the maximum force, tightening strength, yield strength and elastic modulus, are not completely cleaned up, and the bearing raceway is damaged during operation, resulting in excessive temperature rise and burning of the bearing

due to bearing damage and shaft bending, the other is the AD converter. If the number of bits of the AD converter, that is, the resolution is low, the iron core temperature will rise sharply due to stator and rotor friction (commonly known as bore sweeping), and the slot insulation and turn to turn insulation will be burned, resulting in short circuit between turns of the winding or shooting to the ground. In serious cases, the stator core will be reversed, misaligned, the rotating shaft will be worn, and the end cover will be scrapped. Therefore, the damage of the bearing is still serious, so once we find it, we should repair the motor as soon as possible

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