Characteristic fluting caused by electric arcing. Bearings coated with a ceramic insulating material stop electric arcing (inset). Hybrid bearings that incorporate ceramic rolling elements stop arcing as well.
Rolling-element bearings in electric motors support and locate the rotor, maintain a small and consistent air gap between the rotor and stator, and transfer loads from the shaft to the motor frame. The correct bearings for an application let a motor run efficiently across its design speed range, minimize friction and power loss, produce little noise, and have a long service life.
For example, the deep-groove ball bearings optimized for in-line couplers can overload if motors fitted with them drive a belt pulley. Likewise, motors containing roller bearings for heavy belt loads may prematurely fail when run with an in-line coupler because a minimum load is not maintained.On the other hand, bearings can be quickly ruined when a motor is used improperly.
A deep-groove ball bearing installed on the output shaft of an acinduction motor. The motor end cap supports the bearing outer race.