Long term effects of outdoor environment on unprotected A-C motors

Reliance on motor insulation to provide integral protection against environmental hazards has advanced to where this attribute has become a major, and sometimes determining, motor requirement. Only within the last two decades has insulation technology come of age. No longer a weak link to be protected by bulky enclosures, insulation systems of large motors today can withstand on their own varying atmospheric and unfavorable environmental conditions.