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Abstract
The paper describes photographic techniques and high-speed ciné-cameras which are being used in research and development work on the large high-voltage electrical circuit-breakers used at power-stations. When these circuit-breakers interrupt current an electrical arc is formed between the opening contacts and ciné-photography is used to study the growth and extinction of the arc and the movement of products of arcing. A description is given of the special measures adopted to make it possible to photograph events within the circuit-breakers.
A drum type of high-speed ciné-camera which uses only a metre of film and so allows very rapid film processing is described briefly. For some studies concerned with research into the arc-extinction process an ultra-high-speed camera of the image sampling type is used. The principle and development of this camera which gives a ten millisecond time coverage at 500,000 frames-per-second are discussed. Both monochrome and colour materials have been used for the high-speed and ultra-high-speed work and some special problems of the use of colour materials are considered. The use of monochrome films with very thin emulsions to improve the definition of ultra-high-speed films is discussed.
The volume of high-speed ciné-photographic work involved by the present use of five high-speed and one ultra-high-speed ciné-cameras has led to the formation of a special professional photographic section to advise on this work. The organisation of this section is considered briefly.