GB189809511A - Improvements in Rheostats for the Graduated Control of Electrical Resistance, particularly applicable to the Production of Theatrical Luminous Effects. - Google Patents

Abstract

9511. ClÚmanþon, C. E. April 25. Indicating at a distance electrically.-A rheostat a, applicable for regulating lamp circuits for stage lighting and for other purposes, may be rotated by electric, gas, water-pressure, or other motors, which may be controlled from a distance. A method of controlling an electric motor f for this purpose is specified. In order to indicate near the controlling-switches the position of the rheostat a, the drum of this carries a number of projecting studs e and springs, which come in contact with a lever n, and thus intermittently close an indicator circuit. This circuit includes the armature g of a polarized relay, the magnet of which is in the motor armature circuit, so that the relay armature completes the indicator circuit through either of two magnets E<1>, E<2>, depending on the direction of the motor current. These magnets have spring- actuated armatures formed as pawls, acting oppositely on a ratchet-wheel i, which carries a pointer o. Each current received from a stud e on the main rheostat a thus moves the pointer a step forward or backward in accordance with the direction in which the motor and rheostat are moving. In order that reversal of the motor current while the lever n is on a stud e may not operate the indicator, the indicator circuit includes an electromagnet E<4>, which lifts the contact-lever n from each stud on to an adjacent supporting-spring p, immediately after contact has been made.