A new high-capacity air breaker

Air circuit breakers for lower voltages of simple design are being replaced by improved types, which incorporate specially designed circuit-interrupting devices for the purpose of improving the interrupting efficiency and minimizing the formation of arc flame and gases. A new form of deionizing arc interrupter is described which is equally effective for both d-c and a-c circuits. A new air circuit breaker has been designed to utilize this interrupter in which carbon arcing contacts are replaced by refractory metal, and laminated-brush-type main contacts are replaced by silver-faced solid copper. These improvements have led to greatly increased current-carrying capacity in breakers of a given size and also large increases in interrupting capacity with a minimum of noise and flame, which permits the breakers to be readily mounted in enclosures and cubicles of small physical size.