A pneumatic mechanism for outdoor oil circuit breakers

A. W. Hill (Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pa.): The authors have presented a very interesting discussion of the various methods of closing circuit breakers and have brought out particularly well the advantages obtained with the use of compressed air where modern high-speed breaker performance is required. It has been found that while pneumatic mechanisms represent somewhat of a change in maintenance problems, the trade in general has accepted this type of apparatus, and in fact showed a preference for it, especially for high-voltage outdoor breakers where unproved system performance can easily be secured from the faster breaker reclosure. It has been found that a pneumatically trip-free mechanism built along the same lines has found so much favor with purchasers of this equipment, that during the past three years more than half of the oil breakers rated 115 kv and above built by the Westinghouse Company have been equipped for pneumatic operation.