GB588704A - Improvements relating to electrically actuated remote-control apparatus - Google Patents

Abstract

588,704. Electric control systems. ROTAX, Ltd., and ARNOT, A. R. E. March 5, 1945, Nos. 5478 and 22759. [Class 40 (i)] [Also in Group XXXVII] In a system in which a receiving potentiometer is driven into correspondence with a sending potentiometer, each potentiometer comprises a main and a subsidiary part which control respectively two polarized relays by which one or other of two motor-controlling contactors is energized. The relays or the contactors also control braking, or other retarding means which comes into action when correspondence is nearly achieved. The retarding means may be an interrupter in the motor circuit. Fig. 1 shows master and followup potentiometers each comprising a main resistance u connected across the supply and having a contact v mounted on spindle w, and a short subsidiary resistance x in parallel and having two sets of alternately arranged contacts mounted on slip rings 2, 3. If the potentiometers are far from a position of correspondence a heavy current flows between the contacts v through winding g of a first relay causing it to operate. Relay windings q or r or both of a second. relay are also energized due to the current lowing between slip rings 2 and 3. Current is applied from one of the contacts p of the first relay to one of contactor wiridings d, depending on the direction of flow of current in winding q, causing its armature e to be pulled up and close contacts f, g and f<1> g<1>. Closure of contacts f, g energizes the motor a through one of its field windings m, and closure of contacts f<1> g<1> energizes a brake release winding k. The motor then drives the potentiometer until it nears a position of correspondence when the current flowing between contacts v is insufficient to energize the first relay and it drops out. Current is then supplied from the contacts p of the second relay through resistances to the windings d so that the armature drops back a little and opens contacts f<1>, g<1> The brake is then applied to the motor causing it to run at a lower speed until a positional correspondence is obtained. In a modification, Fig. 2, a vibratory. interrupter 5, 6 is placed in the motor circuit for retarding the speed of the motor. When both relays are energized, coil 9 of an electromagnet is short-circuited so that closed contacts 7, 8 short circuit the interrupter 5 and current flows continuously to the motor. When the first relay drops out, coil 9 is energized to open contacts 7, 8 and put the interrupter into circuit. The interrupter may be placed in other parts of the motor circuit, e.g. across part of the field winding or across the armature winding. Specification 588,703, [Group XXXVI], is referred to.