A modern portable power supply for use in motion picture production is being used by Walt Disney Productions. It supplements stationary power houses located on studio property and is ideal for use on remot locations where heavy 125/250-v d-c power required for lighting is not available
The advent of motion pictures created a demand for powerful light sources and associated power supplies. The d-c arc lamp in ratings up to 35 kw has become a motion picture industry standard, particularly when color film became availible. This film requires large quantities of the color corrected light of the are lamp to illuminate properly the motion picture sets for the relatively slow-speed color film. A stand ud 125-v d-c generator is used a the power supply for the 85-v arc lamp. Ballast resistors are used in series with each lamp to reduce voltage to the proper operating level and to limit inrush currents when the carbon electrodes are shorted momentarily to strike the arc.
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