GB959611A - Improvements relating to apparatus for testing electrical circuit breakers - Google Patents

Abstract

959,611. Testing circuit breakers. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Jan. 24, 1963 [Jan. 24, 1962], No. 2682/62. Heading G1U. Apparatus testing a circuit breaker TCB (Fig. 1) comprises a circuit supplying a large low voltage current to the test breaker from an AC source V 1 through an inductance L 1 and an auxiliary breaker ACB comprising plural vacuum contact switches P (Fig.2) connected in series branches with current equalising inductances T; a plurality of such branches being paralleled and each switch being independently controlled from means operating all such switches simultaneously. A voltage source V 2 is switchably connected through a resistance to charge capacitor C 2 , which is dischargable over spark gap G, inductance L 2 and capacitance C 1 to produce in the test circuit breaker a small additional test current and a high test restricting voltage; C 1 and L 2 being equivalent to the capacitance 1 and inductance of the working circuit of TC. On closure of ACB a large current flows at low voltage through TCB which opens. At a required instant of the current cycle, ACB opens trigger gap G, and the requisite test current and restrike voltage are applied; the opening of ACB preventing application of the latter voltage to the current supply circuit. The test conditions approximate to those in practical operation.