Tests on and performance of a high-speed multibreak 138-kV oil circuit breaker

This entire program of field tests in connection with the development of this new high-speed interrupter has again demonstrated that no matter how skilled the designers may be, and with the most exhaustive research testing that is possible in factory testing laboratories, it is still necessary to look to actual high-capacity field tests for ultimate confirmation of circuit breaker designs and to bring out possible weaknesses which otherwise may escape disclosure. In this particular development there is no question but that the fundamental design of the interrupter and, in general, its details had been worked out on a sound basis. It is no reflection whatever on the designers that unforeseen weaknesses were disclosed in the tests; on the contrary, it is proof of the soundness of the development that comparatively minor changes based upon the information obtained from the tests were all that were necessary to enable the final design to go through what is believed to be the most severe series of tests yet made on a high-voltage circuit breaker and do so with perfect performance.