Is it feasible to change the grade of the lubricant for the motor shaft bearings?
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One of our company’s 10kV, 1550KW high-voltage motors has experienced repeated issues with the bearing shells; the clearance between these shells was adjusted to be between 0.33mm and 0.37mm during installation. After the bearing shells are installed, the motor is tested with the vehicle unloaded, and the temperature rise curve remains stable. In about 4 hours, the temperature can reach 70°C, and observing through the sight glass reveals that the oil color turns gray. Upon disassembly, it was found that the bearing shells had been pushed aside; this situation occurred after multiple lapping attempts, with only differences in the amount of time required. The motor features air-water cooling and a self-lubricating slinger ring design. Shaft diameter 250mm, rotational speed 375 rev/min. Kunlun 46 turbine oil is being used as the lubricant, and it is now suspected that its viscosity is too low. I seek advice from experts.
Refer to the motor manual or consult the manufacturer
When you say “pushed,” do you mean axially or radially? If it’s axially, then the magnetic center of the motor needs to be taken into consideration!
Whether it is pushed axially or radially, the reason must be thoroughly investigated. A temperature of 70℃ is still acceptable. If you only want to change the oil, you need to use ISO VG32 oil, as this will lower the temperature.
The magnetic center line is very stable; the wear is all radial
Temperature is not the main issue at the moment; what’s a problem now is the abnormal wear of the bearing shells.
The bearing shaves are worn; it’s likely that the motor rotor is out of alignment. Check the rotor’s dynamic balance
Check the contact between the tile back and the tile shell, as well as whether the contact point between the lower tile and the shaft is satisfactory.
Could you send some photos for me to see?
The contact area exceeds 70%; normal scraping and lapping treatment is sufficient