The theory of oil blast circuit breakers

DIRECT experimental proof of the oil blast theory of arc interruption has been assembled. A circuit breaker has been constructed having oil driven between its electrodes at a measurable velocity, and tests show that a correlation exists between the rate of recovery voltage rise and oil velocity. This correlation corresponds to an oil dielectric strength of 55 kv. per 1/10 in. of oil. To determine whether or not this correlation is accidental, relations between voltage and oil velocity and between current and oil velocity have been studied, but correlation does not appear. Impulse tests also have been made on clean and carbonized oils.