MIL-M-17059 Revision A, October 12, 1965
This specification covers 60 cycle, fractional horsepower (hp.), alternating-current, motors for shipboard use.
The motors shall be of the following services, as specified (see 6.1):
Service A - For applications where motors are essential to the Military effectiveness of a ship.
Service C - For applications where motors are not essential to the Military effectiveness of a ship.