Characteristics of Intermittent Carbon ARCS

Although the carbon arc is usually considered as a continuous source of light, the experiments reported in this paper show that it may be used for the generation of light surges as well. If these surges are made to occur at a rate so fast that the arc stream does not have time to deionize between them, then the electrical circuit may be completely broken at the conclusion of each surge and closed again to initiate the next one. For longer periods between surges, a very low maintaining current is employed. The timing and duration of the light pulses are controlled by electronic switching of half-cycle current surges from an alternating-current supply. — For a given size of carbon, much higher brilliancy and candle-power can be obtained in intermittent than in continuous operation; a brilliancy of 1600 candles per sq-mm is reported for a 7-mm carbon of the “Suprex” type. The efficiency of the intermittent carbon arc is limited by the thermal lag in the electrodes, in that they continue to radiate energy for a considerable period after the current is reduced to zero at the end of each surge.

Print ISSN

0097-5834

Published

1941-07

Content type

Original Research

DOI

10.5594/J16553