Applicable to rotating electric machinery which forms part of the propulsion and major auxiliary equipment on internally and externally powered electrically propelled rail and road vehicles. Purpose of this standard is to define ratings, tests, and calculation procedures to permit comparison among machines for similar use, and to allow evaluation of the suitability of machines for a given use. Major auxiliary equipment includes that such as blower and compressor motors, motor-generator and motor-alternator sets, auxiliary generators, and exciters, usually larger than 3 kilowatts.