GB626130A - Improvements in devices for testing short circuit of high power continuous current switches - Google Patents

Abstract

626,130. Detecting faults. ETABLISSE. MENTS MERLIN & GERIN. May 20, 1946, No. 15156. Convention date, Sept. 14, 1943. [Class 37] In order to test high-power D.C. switches without a high-power D.C. generator, there is employed an H.T. alternator rotated at reduced speed or otherwise arranged so that a halfwave thereof is greater than the opening-time of the switch. In a simple form (Fig. 1, not shown), the switch 5 is connected to the source 1 over a switch 4 synchronized with the source, and synchronizing means then produces opening of 5 at a suitable point in the A:C. wave, as illustrated by a curve (Fig. 2, not shown), the adjustment of time of operation &c. being such that the instantaneous voltage across the switch at moment of are-extinction is that of the corresponding D.C. generator. Tests derived from D.C. sources can be still more closely approximated to by adding a further switch 12 in series with, and operated synchronously with, that 5. Their common point is connected to one pole of a D.C. source 14 of voltage of normal switch rating. While 5, 12 are closed, this source yields negligible current, and substantially the same current traverses both switches, but when they both open, the rated voltage of the switch is supplied to its terminals by the source 14. Synchronizing means for 4, 5 are described.