No-break power supply apparatus

Claim 1

A no-break power supply apparatus comprising: a plurality of CVCF's each CVCF having: input breaker means connected to a D.C. power supply; output breaker means connected to a load, D.C. filter means connected to said input breaker means; inverter means constructed of gate turn off thyristors connected to said D.C. filter means for converting the direct current from said D.C. power supply into an alternating current, said inverter means having a bridge circuit having an arm including a parallel circuit including a GTO thyristor and a diode connected in reverse polarity in parallel with the GTO thyristor, a fuse connected in series with the parallel circuit and a fuse melting detector connected across the fuse; protecting circuit means connected to said fuse melting detector in said inverter means for detecting the melting of the fuse corresponding to an accident by the corresponding fuse melting detector in said inventor means, blocking a gate signal supplied to the gates of all the GTO thyristors normally operated by the output of the detector, then supplying an OFF gate signal to the gates of said all the GTO thyristors except the GTO thyristor connected to the arm of the fuse thus melted and supplying a breakage command signal to said input breaker means and said output breaker means;