GB855970A - An installation for testing high-power electric circuit breakers - Google Patents

Abstract

855,970. Electric tests. LICENTIA PATENTVERWALTUNGS-G.m.b.H. Oct. 11, 1957 [Oct. 15, 1956], No. 31820/57. Class 37 In a circuit breaker testing arrangement of the type in which separate high current and high voltage supplies are provided, the alternating high current supply is full-wave rectified in an inductive current the two separate half-waves so overlapping that the current through the breaker does not fall to zero until the contacts are sufficiently open for the re-striking voltage to be applied. In the arrangement shown, the D.C. current through the breaker under test is supplied from the centre-tapped secondary of transformer T the primary of which is supplied from short circuit generator G. Current transformers W1, W2 control the period conductivity of rectifiers V1, V2. The inductance in the rectifier circuits prevents the current from rising and falling instantly so that both rectifier anodes carry current for a time and the total breaker current never falls to zero. Initially the rectifiers may be switched - when the current is zero by a starting impulse derived from a small generator on the shaft of the short circuit generator G. The high voltage current comprises capacitor C charged from a high voltage D.C. source spark gap F, reactor Ls and r-c circuit Rd Cd in parallel with the breaker and acting to adjust the frequency of the voltage and to damp the transient recovery voltage. In the arrangement of Fig. 3. the use of a special rectifier transformer is avoided by the arrangement shown in which the primary of each of transformers T1, T2 is amended in parallel with two phases of generator G.