(under subclass 71) Subject matter having the circuit for controlling the supply of current to the motor controlled by an electric switch, the switch being operated in response to the condition of the electric discharge.
(1) Note. In many of the systems in this subclass, the switch controls a shunt placed about an impedance in the motor circuit, the shunt being opened to place the impedance in the motor circuit to retard the speed of rotation of the motor when the electrodes have been fed almost into contact with each other, thereby preventing overfeeding.
(2) Note. For other electric motor controlled feeding systems wherein the motor rotates at varying speeds, see subclasses 70, 75 and 76 of this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70, for systems under subclass 69 provided with an impedance in the motor circuit which acts as a dynamic brake on the motor when the electrodes have been moved to or almost to the proper position.
73, and 74, for other systems under subclass 69 having switch controlled motor circuits.
SEE OR SEARCH CLASS 318, Electricity: Motive Power Systems,
515, and the search notes thereunder, for electric motor control by switch means in combination with resistance in the armature or primary circuit.
