Most of the reasons for bearing damage are many, beyond the original estimated load, too small bearing clearance caused by non-effective sealing and over-tightening. Any of these factors have their particular type of damage and leave a special mark of damage.
Inspection of damaged bearings can be found in most cases. In general, one-third of bearing damage is caused by fatigue damage, and the other third is due to poor lubrication, other three points One is due to contaminants entering the bearing or improperly installed.
According to analysis, high-voltage motors are mostly end-cap sliding bearing structures and end cap rolling bearing structures. After summing up and analyzing the experience of various high-voltage motor maintenance, we believe that there are the following problems: end cap sliding bearing type: Most of these motors have large axial movements of the rotor, bearing bush heating and oil leakage. Corrosion caused to the stator coil of the motor, and excessive oil and ash accumulation inside the motor, resulting in poor ventilation, causing the motor temperature to be too high and damaged. Sliding bearings are also much more complicated to overhaul than rolling bearings.
Box-type high-voltage motor: This motor is a new type of motor produced in China in recent years. Its performance and shape are superior to JS series motors. However, some of the motors produced by some manufacturers have some defects in the design of the bearings, resulting in more bearing failures in the running of the motor. The structure of these motors is to have a oil retaining disc with a small clearance from the bearing on the outside of the bearing, so that the grease inside the bearing can be kept sufficient, but this structure has the following disadvantages:
Due to the existence of the bearing oil retaining plate, the motor can not be inspected when the motor is under minor repair. When the motor is overhauled, the bearing can not be cleaned without removing the oil retaining plate, and only the replacement can cause unnecessary waste. It is not conducive to the heat dissipation of the bearing and the circulation of the grease, so that the temperature of the bearing rises during operation, the performance of the grease is lowered, and the vicious cycle of the temperature rises again, which causes the bearing to be damaged. Due to the need to disassemble the oil retaining disc and the replacement of the bearing during multiple inspections, the loosening of the inner hole of the oil retaining disc and the shaft causes the oil retaining disc to escape from the shaft during operation, causing a malfunction.