GB352116A - Improvements in and relating to resistance controllers for electric circuits - Google Patents

Abstract

352,116. Master control of motors ; drum controllers. SEEGER, E. W., 12th Street, Milwaukee, Wisconsin, U.S.A. April 15, 1930, No. 11933. Convention date, June 7, 1929. [Class 38 (iii).] With auxiliary switches.-To vary resistance in a circuit a number of sections initially connected in series, are used, and steps of resistance variation are effected by cutting out one section, then cutting out a second section and re-including the first, and then subsequently re-excluding the first section while maintaining the second excluded, a device being provided for positively ensuring that when one resistance is cut in and another cut out, such cutting in and out shall take place instantaneously. Resistances R1 .. R4 in another circuit are shortcircuited by switches 1a .. 4a operated by an electromagnetic relay C, governed by a controller D. The resistances may have values of 1, 2, 4, and 8 ohms respectively, and when the controller is in its first position a coil M is energized to close a switch Ma, so that the motor A is in series with 15 ohms. In the second position the relay C is energized and contacts C1, C2, C4, C6 are closed, the closure of C1 energizing switch la and removing 1 ohm from the circuit. In the third position, the relay C is de-energized and contacts C3, C5, C7 close, so that the switch 2a is closed and switch 1a opened, 2 ohms being removed from the circuit. At the next step both switches 1a and 2a are closed so that 3 ohms are removed. This continues until all the resistance has been removed in steps of 1 ohm. After the first position of the controller, the coil M is maintained energized by auxiliary contacts Mb, so that if the supply voltage fails the controller must be removed to its starting position before the motor circuit can be closed.