When circuit-breakers are called upon to interrupt high voltages and high power, and to prevent voltage surges being imposed upon the connected electrical system, it is occasionally desirable to employ a shunting resistor. U.S. Pat. No. 2,911,546, issued Nov. 3, 1959 to J. A. Oppel, illustrates a general type of shunting resistor application. See also, additionally, U.S. Pat. No. 3,114,816, issued Dec. 17, 1963 to John W. Beatty, and U.S. Pat. No. 3,482,069, issued Dec. 2, 1969 to Badey et al.
It is well known by those skilled in the art that the use of a shunting resistor damps the recovery-voltage transient during the opening stroke of the circuit-breaker. See, for example, U.S. Pat. No. 3,390,329, issued June 25, 1968 to R. H. Miller. This has the advantage of rendering the electrical circuit easier to interrupt; however, due to the additional complication of a resistor assemblage and its own individual series resistor break, generally, the overall time of interruption of the circuit-breaker is lengthened. U.S. Pat. No. 3,267,241--Wilson, however, illustrates for example, a high-voltage, high-power compressed-gas circuit-breaker, which the manufacturer claims is capable of two-cycle interruption. In this particular circuit-breaker, a resistor is employed in shunting relationship with the main power break. During the closing operation, the resistor circuit is closed prior to the closing of the main power contacts. See also U.S. Pat. No. 3,211,868, issued Oct. 12, 1965 to Barkan et al.