| 摘要 |
PURPOSE:To save the number of components without losing the safety to electric shock at inspection, by triggering an auxiliary thyristor and discharging the charge of a capacitor, through the opening of a capacitor charge switching at the maintenance and inspection of a semiconductor breaker. CONSTITUTION:At the maintenance and inspection of a semiconductor breaker, a charging switch 14 is opened with an open signal 19-1 from an inspection signals 19 to stop the charging function. At the same time, an inspection delay signal 19-3 expecting the delay in opening operation of the switch 14 at a delay circuit 20 passes through an OR circuit 21 to output a trigger signal 22 and to trigger an auxiliary SCR5. Thus, the charge of a commutation capacitor C3 is discharged via a diode 10 connected anti-parallel with a reactor 4, the SCR5 and a main SCR1, the polarity of charging charge of the C3 is inverted, allowing to discharge the charge of the C3 with a loop 15 through a resistor 13 and a rectifier 12. The charging and discharging circuit of the C3 is not added with any special circuit, allowing to guarantee the safety to electric shock. |
