Most motor failures are caused by a combination of various stresses that act upon the bearings, stator, rotor, and shaft. If these stresses are kept within the design capabilities of the system, premature failure shouldn't occur. However, if any combination of the stresses exceeds the design capacity, the life of the system may be drastically reduced and catastrophic failure could occur.
These stresses are classified as follows:
* Bearing stresses
Thermal, dynamic and static loading, vibration and shock, environmental, mechanical, electrical
* Stator stresses
Thermal, electrical, mechanical, and environmental
* Rotor stresses
Thermal, dynamic, mechanical, environmental, magnetic, residual, and miscellaneous
* Shaft stresses
Dynamic, mechanical, environmental, thermal, residual, and electromagnetic
