I thought we had a case shorted RS775, the motor ran fine for break-in, and for a while after that during testing. Then it seized and popped the fuse we had in-line. After taking the case apart to investigate (a problem I have had since a young age
) I discovered the culprit to be a common paper staple had gotten between the magnets and rotor. I removed the offending staple and reassembled the motor, and it works, but now there is some endplay in the shaft. On a side note these motors were shipped strait to our shop, and used only there (we do not have paper staples in our shop) everything is in three hole binders.