13 common causes of motor failure 

13 common causes of motor failure.
Power quality
1 - Transient voltage
Impact: Motor winding insulation breakdown leads to early motor failure and unplanned downtime
2 - Voltage imbalance
Impact: Imbalance creates excessive current flow in one or more phases that then increases operating temperatures-leading to insulation breakdown
3 - Harmonic distortion
Impact: Decrease in motor efficiency results in added cost and an increase in operating temperatures
Variable frequency drives
4 - Reflections on drive output PWM signals
Impact: Motor winding insulation breakdown leads to unplanned downtime
5 - Sigma current
Impact: Mysterious circuit trip due to protective earth current flow
6 - Operational overloads
Impact: Premature wear on motor electrical and mechanical components leading to permanent failure
Mechanical
7 - Misalignment
Impact: Premature wear in mechanical drive components that leads to premature failures
8 - Shaft imbalance
Impact: Premature wear in mechanical drive components that leads to premature failures
9 - Shaft looseness
Impact: Premature wear in mechanical drive components that leads to premature failures
10 - Bearing wear
Impact: Accelerated wear on rotating components resulting in bearing failure
Improper installation factors
11 - Soft foot
Impact: Misalignment of mechanical drive components
12 - Pipe strain
Impact: Shaft misalignment and subsequent stresses on rotating components, leading the premature failures
13 - Shaft voltage
Impact: Arcing across bearing surfaces create pitting and fluting resulting in excessive vibration and eventual bearing failure