Transformers Components internal oil-immersed secondary circuit breakers are designed for use as part of a protection package for either single or three phase distribution transformers. The circuit breaker permits operation of the transformer at loads exceeding its continuous self-cooled rating during short time peaks.
The circuit breaker trips due to heat from the combination of transformer current and the temperature of the transformer oil. Optional magnet trip circuit breakers follow the same interrupting characteristics as the normal breaker except the breaker will immediately trip when the current exceeds 10-15 times rated transformer load current.