.~ Slipping and/or racing control for electric motors
DEFINITION
Classification: 318/52
(under subclass 34) Subject matter in which means are provided for reducing the speed of, or reducing the electrical power input to, one or more electric motors when one or more of the electric motors is slipping or racing while operating as a motor.
(1) Note. This subclass includes means which sense: (1) A sudden increase in speed (that is, a high rate of change of speed) of one or more electric motors, or (2) A speed of one or more electric motors the speed of which is considerably in excess of normal or rated speed thereof, or(3) A substantial change in the relative speeds of two or more motors connected to operate a common load device or physically interconnected load devices so that the motors normally tend to operate at a predetermined ratio of speeds and effects a reduction in speed of one or more of the motors when the above speed conditions exist.
(2) Note. "Slipping" usually occurs when the motor fails to drive its load, through failure of the mechanical connection between the motor and load, and thereby increases its speed due to a lack of load on the motor. An example of slipping is the case of a traction motor driving a wheel, the wheel may fail to grip the rail or road bed and "spin", thereby reducing the load on the motor.
(3) Note. Where the control means affects the operation at all speeds loads such as maintaining the speed of or load on the motor or motors constant, or maintaining a predetermined load division between several motors, classification is not in this subclass, but is classified herein below in the appropriate subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
68+, for plural motor systems having relative running speed control of plural motors. 98+, for plural motor systems having loads or currents division between two or more motors.
