Improved selective tripping of low-voltage air circuit breakers

L. C. Peterman (nonmember; Ford, Bacon, and Davis, Inc., New York, N. Y.): The announcement made in this paper of the new selective tripping mechanism for air circuit breakers indicates that we now have low-voltage direct-tripping devices that will give a performance on overloads comparable to that secured with relays, shunt trip and storage battery, such as customarily are applied only to high-voltage circuits. Further, the inherent nature and simplicity of the direct-acting trip should give high-speed action where that is required, equal to the highest speed now available from the relay-shunt-trip combination, coupled with great reliability due to the smaller number of parts involved in the tripping action.