GB822211A - Improvements in or relating to electric circuit arrangements for the control of stage lighting and analogous uses - Google Patents

Abstract

822,211. Supply and control systems for stage lighting equipment. GENERAL ELECTRIC CO. Ltd. June 19, 1958 [June 19, 1957], No. 19352/57. Class 38 (4). A circuit arrangement for the control of stage lighting or similar apparatus in which combinations of states of brightness of the lighting can be pre-set by setting up suitable electrical connections and in which the transition from one state of brightness to another can be made smoothly and quickly comprises two transformers A, B, the primary windings of which are connected in series across an alternating current supply XY and an autotransformer W also connected across the supply, an adjustable tapping T on the autotransformer W being connected to the connection between the primary windings of the transformers A, B. The secondary windings of the transformers A, B are provided with a number of fixed tappings which are connected in any desired fashion to the terminals on a control panel P, these terminals being also connected to the contacts of a number of switches SL, SM, SN, the movable arms Sa of which are ganged together and control the a windings of the controlled elements LC, MC, NC, the movable arms Sb being ganged together and arranged to control the b windings of these elements. Thus the voltages selected by the connections between the transformers A, B and the panel P are supplied as desired to the windings a, b by suitable operation of the switches SL, SM, SN and these voltages may be smoothly varied by movement of the tapping T along the autotransformer W whereby the voltages applied to the primary windings of the transformers A, B are simultaneously varied in opposite senses. A potential divider may be employed instead of the autotransformer W and a voltage distributing arrangement instead of the transformers A, B. The tapping T may be motor-driven and the switches SL, SM, SN automatically operated. The windings a, b may be the primary windings of transformers the secondary windings of which may be associated thyratron or saturable reactor circuits to vary the lighting brightness.