General:

This recommended practice establishes objectives for high performance control motor tachometer generators to be used with aeronautical and associated equipment in protective enclosures or completely within the shell of the aircraft so that they are subjected only to the internal climatic conditions of heat, cold, shock, vibration, and humidity. Control motor tachometer generators larger than size 23 are not covered in this document.

Type Designation of Control Motor Tachometer Generators:

Control motor tachometer generators are classified according to frame size, control winding voltage, power supply, variable, and environmental capability. The prefix M. G. in the frame size designates a motor generator.