Improvements in Moderate Capacity Oil Circuit Breakers

The increased duty requirements of power station service require circuit breaker design to give maximum interrupting capacity in a minimum of space. Compact, relatively high-power breakers having all three poles in a single round tank have been designed, which, in addition to increase in the rating for a given space, give improved performance over types previously available. The relations of the current-carrying loops inside the breaker and the diversity factor afforded by the common oil volume and air space give superior results in operation. This type of design permits use in current ranges where decreased arc energy, as compared to power handled, can be secured.