A compressed-air operating mechanism (or oil circuit breakers

THE recent trend toward better use of existing lines and power sources has brought a demand for faster operation of oil circuit breakers and further simplification of control. In the past it has been common practice to use a solenoid or motor to provide closing energy for these breakers, either of which requires a substantial battery, means for keeping it up to full charge at all times, large conductors between the battery and the breaker to handle the heavy currents which exist for approximately one second while the breaker is closing, and generously proportioned control equipment. Consequently, the cost of apparatus associated with the breaker, but actually installed apart from the breaker, becomes a significant item.