Patent GB-475135-A (GB)
Title: Improvements in or relating to the control of electric lighting systems for theatres, cinemas, ballrooms or other buildings in connection with which lighting of variableeffect is required
IPC: H05B37/02
Filed: 1936-05-18
Abstract: 475,135. Supply systems for con sumption apparatus ; commutator switching arrangements. STRANI ELECTRIC & ENGINEERING CO. Ltd., and BENTHAM, F. P. May 18 1936, No. 14018. [Classes 38 (ii) anc 38 (iv)] [Also in Group XXXVII In theatre or similar lighting systems, a variable effect is obtained by two sets of manually-operated members, one of which from a number of lighting circuits, selects those to be used to secure a given effect while the other set determines direction and rate of variation of intensity and also applies power to selected circuits. In the system shown in Fig. 1, each dimmer or group of dimmers (not shown) is actuated by a device such as a reversible motor which is moved in either direction in response to the energization of the associated exciting coil 1 or 2 to increase or decrease the illumination. Switches 5 select the dimmer circuit and switches 6 select either coil 1 or coil 2 for increase or decrease. The rate at which such increase or decrease shall take place in each case depends upon the setting of the appropriate switch 19. Any of these switches, when adjusted to the right, supplies full current across the mains 3, 4 through busbar 15. Adjustment of the switches to other positions supplies interrupted current through bus-bars 16, 17 or 18 and the connected rotating interrupters 7, 8, 9, each of which consists of drums mounted on a common shaft, but having different numbers of conducting segments cooperating with bushes 14, thus cutting down more or less the current energizing the coils 1 or 2. In a modification, switches 6 are provided with an off stop so that switches 5 may be omitted. A duplicate set of control switches 19 may be provided', either set being connected to the coils 1, 2 as required by a switch, thus enabling one set to be preset while the other is in operation. In the system shown in Fig. 5, six reversible motors or other operating element are each supplied with current through one of the leads 46 to increase illumination or similarly through one of the leads 47 to decrease illumination, the full current being supplied from mains 3, 4 or from one of the leads 52 connected to interrupters of various frequencies. Switch 34 operates electromagnet 35 or 36 to move the corresponding series of contacts 43 downwards. Switches 32 energize electromagnets 33 which then raise corresponding conductive bars 42 so as to engage the appropriate contact 43, switches 32 thus selecting one or more of the motors connected to leads 46 or 47 for dimming or increase. Switch 37 moves downward one of the bars 48, 49, 50, 51, carrying contacts 43 which then engage the horizontal bar or bars which have been raised by operation of switches 32 thus supplying full current or interrupted current of the desired frequency. In a modification of the system, the number of bars is reduced. The bars 48, 49, 50, 51 are replaced by a single bar which is moved into operation position by continuous current energization or is reciprocated at a rate depending upon which of the interrupters it is supplied from. The rotating interrupter for supply current of several frequencies may be constructed as shown in Figs. 2 and 3, in which discs 20 fixed on the shaft carry several circles of pins 11, each circle having a different number of pins. The pins co-operate with adjustable spring contacts 14. The circuit is completed from the brush 13 through the pins 11 to the selected arm 14. Specification 373,625, [Group XXXVII], is referred to.