831eb72a_es_content_from_Machine_Design__Induction_motor
[0] RELIABILITY [PMAC] Lower operating temperatures reduces wear and tear, maintenance • Extends bearing and insulation life • Robust construction for years of trouble-free operation in harsh environments [Servomotor] Physical motor issues minimal; demanding servo applications require careful sizing, or can threaten failure [Induction motor] 
Waste heat is capable of degrading insulation essential to motor operation • Years of service common with proper operation
The difference between AC induction, permanent magnet, and servomotor technologies | Motors/Drives content from Machine Design
Induction motor