Compressed air circuit breaker for high currents

INDUSTRIES USING large concentrations of electric power at generated voltages have created a demand for circuit breakers and associated switchgear for operation at generated voltages of 12,000 to 15,000 volts, a-c, and at continuous current ratings in excess of 5,000 amperes. The maximum standard current rating for station-type cubicles is 5,000 amperes and is limited by the maximum current rating of the circuit breaker. The problem, therefore, was to increase the limitation imposed by the breaker. The design which resulted is shown in Fig. 1. In reviewing the developments of the last 40 years in electrical engineering as applied to tankers the great increase in use and types of applications is emphasized. Electrical consumption has grown from a few to tens of thousands of kilowatt-hours. It is now vital to propulsion, navigation, communication, cargo handling, cooking, safety, and entertainment.