GB392525A - Improvements in and relating to electric control systems - Google Patents

Abstract

392,525. Control of D. C. motors. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees 'of Fitzgerald, A. S.; Warwick Road, Wynnewood, Pennsylvania, U.S.A.) Aug. 14, 1931, No. 22968. Convention date, Aug. 14, 1930. Void [Published under Sect. 91 of the Acts]. [Class 38 (iii).] Reversing.-In a distant control system, more particularly for controlling the movements of a toy train, hoist, &c. control circuits are selected by a stepping switch which is operated by impulses produced in response to the syllables or distinct sounds of speech. As shown in Fig. 1, a locomotive 1 is driven by a motor 2 energized from the track 6, 7 which is supplied from a motor 2 energized from the track 6, 7 which is supplied from a source 9 with potential of either polarity by means of a reversing switch 8 to effect reversal of the motor. The switch 8 normally occupies a mid position under the control of springs 10 to disconnect the supply from the track, but may be actuated into either operative position by magnets 11, 12 which are under the control of relays 19, 20. The switch is locked in its operative positions by latches 13, 14 which may be retracted by magnets 15, 16 under the control of a'relay 21. The relays 19, 20, 21 are connected to the contacts of a stepping switch 30 controlled by a relay 26 which is operated by impulses derived from the syllables of speech spoken into a microphone 29 and passed through a detector 17. According to the number of syllables or distinct sounds in a command given by the operator, the stepping switch is operated into a selecting position to effect a desired control e.g. two or three impulses operate the switch 8 into one or other of its operative positions to control the direction of travel of the train and one impulse effects release. The relays 19, 20, 21 are slow-acting to prevent operation during movement of the switch 30, but upon actuation by the final' impulse, the inertia of the switch maintains the contact for a period sufficient to allow operation of the associated relay prior to the return of the switch under spring control. The motor on the locomotive has a series winding 3 connected across a bridge arrangement of valve or metal rectifiers, which ensure a unidirectional field current when the direction of current through the armature 2 is reversed to effect reverse running. In a modification the relay 26 is normally energized, and impulses effect corresponding de-energizations to operate a stepping switch having. two wipers and an electromagnetically operated detent for locking the switch in its selecting positions. Upon termination of a selecting operation, a slow-acting relay is operated over off-normal contacts of the switch to effect the supply of energy to the track conductors over the switch wipers. Instead of reversing the polarity of supply to the track, the character of the supply may be otherwise varied, e.g. by varying the magnitude of potential or the frequency if an a.c. source is employed.