400HP vertical mounted motor on cooling tower water pump. MOB (Fafnir 6226 ball) has fluting. First time I have seen fluting signature oppose one another from inner race to outer race. Is this common in thrust loaded vertical mounted motors? Second question, MIB (7228 SKF ball) has distinct rolling element paths in four separate location on outer and inner bearing races. These do not intersect around the races. I am at a loss as to why this pattern was discovered on a destruct test of bearing. Might this be a signature of the motor hunting magnetic center? Has anyone ever seen this pattern? Will post picture of inner race of MIB if able.

Is the motor being operated by a VFD?

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First time I have seen fluting signature oppose one another from inner race to outer race.

Can you clarify what you mean by "oppose one another"?

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Second question, MIB (7228 SKF ball) has distinct rolling element paths in four separate location on outer and inner bearing races. These do not intersect around the races. I am at a loss as to why this pattern was discovered on a destruct test of bearing. Might this be a signature of the motor hunting magnetic center? Has anyone ever seen this pattern? Will post picture of inner race of MIB if able.

This motor apparently has deep groove ball bearing on top and angle contact thrust bearing on bottom. Is there only one bearing on the bottom or back to back?

I haven't seen it, but it seems like that pattern you describe might occur if the endplay was excessive and the external thrust loading was variable (perhaps at time below the minimum required for this bearing).

Yes, the motor is driven by a VFD controller. Motor is a six pole, 1200 motor.

My apologies the inboard bearing is a 6226 ball bearing with the four rolling element paths that do not intersect. The outboard bearing is a angular contact (thrust preloaded) bearing having the opposite fluting paths from inner race to outer race.