we have Propylene Transfer Pump Motor. The unit is newly repaired and overhauled, but after operating for a period of 10 to 15 minutes, it trips and found broken bearing inside. I would like to know what’s the real reason of bearing damage.

highlights:
1. The pump motor unit running hours before the most recent overhaul is approximately 26,760 hours.
2. The pump motor unit started twice in reverse direction for approximately 15 minutes and 8 minutes respectively (time difference was 45 minute)
3. The direction of the pump motor unit rotation was corrected after interchanging the connection and it runs for 10 minutes, then trips.
4. After removal of the pump motor unit from the tank, nitrogen was applied to the pump motor unit to melt/remove the ice (the unit was already on the ground and they applied nitrogen with two hoses on the holes of the pump directly. Reference to this, is there any effect on the pump casing and/or is there any thermal stress?)

Best Regards,