A vertical-flow outdoor compressed-air breaker

The elimination of oil in indoor circuit breakers, particularly for powerhouse use, has been insistently demanded to reduce fire hazard. In an effort to meet these requirements, various types of breakers not containing oil have been built and studied. Self-contained breakers of the “De-ion” type¹ have been available for several years, and the potentialities of water breakers² have been carefully investigated. Compressed-air breakers³ for this service have been successfully developed, particularly to meet high kilovolt-ampere interrupting requirements, and the circuit-rupturing ability of these devices has been so amazingly efficient that experimental breakers using this principle have now been built and tested for high-voltage outdoor application.