A New 15-Kv Pneumatic Circuit Interrupter

The demand for oilless circuit breakers of large interrupting capacity to meet the requirements of American practice directs attention toward an improved compressed-air circuit breaker which materially extends the present limitations as exemplified by continental designs. A brief historical review of the trend toward oilless-circuit-breaker development is given. The comparison is made of the available methods of circuit interruption in air. The particular applicability of compressed air is stressed and a new circuit interrupter is described which can reach an interrupting capacity of 1,500,000 kva at 15,000 volts, Among the outstanding features of this interrupter are extremely high operating speed and rapid interruption with minimum energy dissipation. Test results are given indicating the adequacy of this type of design.