(under subclass 29) Subject matter wherein a tachometer device is utilized to produce an energy output which is a measure of the speed and such output is used to provide the control.
(1) Note. Although the tachometer device is in most cases an electric generator whose output voltage or frequency is proportional to the speed, other devices are also used (e.g., pumps etc.).
SEE OR SEARCH CLASS
310, Electrical Generator or Motor Structure, appropriate subclasses for tachometer generators, per se.
324, Electricity: Measuring and Testing,
160+, for speed measuring systems using a tachometer generator.
361, Electricity: Electrical Systems and Devices, 236+, for speed responsive systems using a tachometer generator.
388, Electricity: Motor Control Systems,
800+, for running-speed control systems including a feedback device responsive to the speed of the motor.
