NEMA SM 1 : 2017

Provides general-purpose synchronous motors without excited rotor windings, including polyphase alternating-current permanent magnet motors rated 500 horsepower and less, designed in standard ratings with standard operating characteristics and mechanical construction for use under usual service conditions without restriction to a particular application or type of application, and incorporating all of the following: a.Across the line starting b.Permanent magnets in the rotor c.Open or enclosed construction d.Rated continuous duty e.Class B or higher rated insulation system with a temperature rise at rated load not exceeding that specified in 7.15 for Class B insulation.