The Cross-Air-Blast Circuit Breaker

The designs of European air-blast circuit breakers are not wholly satisfactory for operation in the United States as they do not handle high enough currents, cannot economically be built for high enough interrupting capacities, and do not conform to United States installation arrangements. Accordingly, a new type of air cross-blast circuit breaker has been developed which does conform to the above requirements. The commercial design of this circuit breaker is discussed in a companion paper ``Design and Construction of High-Capacity Air-Blast Circuit Breakers´´ by Messrs. H. E. Strang and A. C. Boisseau, and the present paper analyzes the theory of performance of the foreign and cross-blast circuit breakers, and presents evidence from a number of sources which throw light on the method of operation. The circuit breaker is found to operate predominately on the displacement theory. The nature of its performance makes it much less sensitive to recovery rate and high currents and much more economical in air consumption than air-blast breakers previously available.