| 摘要 |
<p>PURPOSE:To reduce the quantity of wiring or checking work, by charging the condenser of an arc extension circuit with the voltage of a low voltage current source. CONSTITUTION:At first, a protective breaker Sb is closed to excite the primary winding of a transformer TR and, next, a closing switch Sc is closed and a short-circuit current Ig is supplied to a series circuit of a breaker Sp tested held to a closed state preliminarily and an auxiliary breaker Sh and the breakers Sp, Sh are simultaneously closed at the proper point of time of a current waveform. Herein, since the voltage of a low voltage current source is lower than the rated voltage of the breakers Sp, Sh, the current Ig is ready to be blocked at the point of time T11 corresponding to said voltage. A discharge gap Gp is operated at the point of time T01 immediately before the point of time T11 and the voltage Vp of a condenser Cp charged before the switch Sc is closed is discharged. The discharge current Ip at this time flows through the breakers Sh, Sp in series to be superposed on the current Ig and the waveform of a synthetic current is steeply reversed in polarity immediately before the natural zero point of the current Ig to forcibly allow the current Ip to pass the zero point and first breaking is completed while withstanding the voltage of a high voltage supply Cv applied immediately before the final half wave zero point position T21.</p> |
