Patent GB-386378-A (GB)
Title: Improvements in or relating to illumination control system
IPC: G05F1/648
Filed: 1931-10-12
Abstract: 386,378. Control systems for lamps. IGRANIC ELECTRIC CO., Ltd., 147, Queen Victoria Street, London.-(Assignees of Hunter, R. B. ; Shorewood, Wisconsin, U.S.A.) Oct. 12,- 1931, No. 28290. Convention date, Oct. 11, 1930. [Class 38 (iv).] A group of lamp circuits 10, 11, &c. is associated with individual preselecting elements 29 to determine in advance the current intensity in each circuit, individual actuating devices, each comprising a double rack member 50 and a continuously driven pinion 51 whereby a rheostat arm 14 may be operated to effect the preselected intensities gradually, individual intensity control elements 63 whereby the actuating devices may be individually rendered effective and a joint intensity control element 65 whereby the actuating devices of a given number of lamp circuits may be jointly rendered effective. Further, a common joint intensity control element 67 may be provided whereby the actuating devices for all the lamp circuits may be jointly rendered effective. Continuity control elements 22 may be provided for individual control of the energization of the circuits and these may be supplemented by joint continuity control elements 26 for joint energization of a given number of circuits and by a common joint continuity control element 28 by which the lamps of all circuits may be jointly energized. The current intensity in each lamp circuit is varied in accordance with the movement of a following element 30 moved by the respective actuating device in common with the rheostat arm 14 and by means of a polarized relay 35 connected between the following element 30 and the presetting element 29, the actuating device is only ineffective when the positions of the elements 29, 30 correspond, these elements travelling over corresponding resistances arranged in Wheatstone bridge relationship. The relay 35 controls magnets 44, 46 determining the engagement between the pinion 51 and either rack on the member 50. The pinion may be driven by an electric motor the speed of which, and therefore the rate of change of lamp current, may be determined by a rheostat 57 in the motor circuit. Means such as press-buttons 61 individually operable at will independently of the presetting and intensity control elements may be arranged to render the actuating device effective to reduce the current intensity in each circuit. These press-buttons may be mechanically or electrically associated so that all or certain of the relays 68 may be controlled by one button. The position of the following element 30 and the intensity of current in each circuit may be indicated by a voltmeter V. The dimmer rheostats 14 may be replaced by equivalent regulating devices, e.g. saturable choke dimmers. The rack and pinion actuating means may be substituted by other forms of driving mechanism or may be connected in groups to common driving motors or all may be driven by a single motor. Reversible motors may be employed. Transfer of control from the individual intensity control elements to joint intensity control elements may be effected by jointly disabling the Wheatstone bridge circuits. The controlling elements may be grouped on a panel.