> > > >

1948-49 Theatre Catalog, 7th Edition, Page 58 (48)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 58
Page 58

1948-49 Theatre Catalog, 7th Edition, Page 58

PracticalNotes on Theatre Wiringi

Fundamentals That Apply to the Usual Electrical Equipment and Lines for Power and Lighting

This article presents information on electrical circuits for power and lighting requirements in the modern motion picture theatre. General lighting and power systems, emergency equipment, sign lighting, projection room light and power, and miscellaneous circuits and control panels are discussed, and preferred installations described. Recommendations, based on experience, are given for wiring and control installations found to be most satisfactory from a functional standpoint.

Electric Wiring

The electric lighting and power requirements of the motion picture theatre will require at least four separate distribution centers or panels, namely, the general lighting panel, with a supplementary ten- or twelve-circuit panel in the projection room, a Sign lighting panel controlling exterior signs, a power panel for controlling the motors required for the mechanical equipment, and an emergency lighting panel controlling all emergency lighting.

General Lighting Panel

This panel should be located in or adjacent to the managers office, and should control all the circuits for the lighting in the auditorium, foyers, 10bbies, toilets, etc., and also the stage lighting. However, auxiliary controls for the auditorium and stage should be located in the projection booth to enable these lights to be properly controlled in conjunction with the projection of the picture. In some localities union regulations require these lights to be controlled by stage-hands, in which case, these controls will be located on stage and operated in response to buzzer signals from the booth.

In other instances where more extensive stage lighting such as footlights, borderlights, stage pockets, and so forth, is required to light vaudeville or other stage attractions, a regular stage switch board will be installed with dimmer controls, etc., and all stage and house lighting will be controlled from this board. In such cases only the lighting circuits for the front. of the house, that is, the lobbies, foyers, retiring rooms, and so forth, would be controlled from the general lighting


THE ARRAY OF CONTROL SWITCHES AND DIMMERS in an average projection room represents one of the heaviest theatre concentrations of electrical equipment. Here the normal a.c. power lines are converted through generators or recliners into d.c. ior the carbon arc. Here also will be found all necessary wiring for the projection, sound and any special effect equipment plus remote controls for the curtain machine and main auditorium lights. An orderly arrangement promotes efficiency.

This panel will also have one section which will control all emergency and exit lighting required.

Most codes require that the emer-.

gency panel be fed from two different

power sources or substations and be'.

equipped with an automatic 'throwover switch which will operate on failure of the regular power supply. This will furnish enough current to the exit lights, and to lights in the auditorium on the stairs, in the lobbies, foyers, and exterior exit courts to prevent panic in these areas.

Where a second outside source of elece trical energy is not available it will be necessary to provide auxiliary equipment in the theatre to energize the exit and emergency lighting circuits.

If such equipment is required, an automatic generating plant powered by a gasoline motor which will also operate on illuminating gas if available, will prove to be the most satisfactory over a period of years. Emergency sets operated by water power are also available and satisfactory for smaller theatres. Storage batteries with trickle chargers for either 32 volts or 120 volts are also available. If a 32-volt set is used it will require separate wiring to all emergency lighting and diderent lamps from those in general use on the 120-volt circuits throughout the house.

Sign Liglrl-ing Panel

The sign panel, which will control all the exterior display lighting, should also be located in or near the managers office. This panel should have separate controls for the vertical sign, changeable letter panel lighting, and at least three controls for the marquee soflit. In addition to the above mentioned controls provision should be made on the panel for a flood or spot light circuit, one for flashing borders, and at least two spares. The load controlled by this panel will be from 15 to 25 kw. depending on the size and design of the exterior lighting. The branch circuits from this panel should be extended to a weather proof accessible pull box in the front wall of the theatre just above the marquee roof. The branch circuit wiring to this pull box should be left sufficiently long for the sign contractor to make proper connections to the sign wiring.

Proieci'ion Room Light and Power

The projection room a.c. requirements will be a branch feeder from the main lighting panel to a ten- or twelve-circuit panel in the projection room wall, and branch feeders from the main power panel to location of motor generator sets for supplying dc. current to the projection machine arcs, and in some cases to spotlights or effect machines. Provision


l i l
1948-49 Theatre Catalog, 7th Edition, Page 58