| 摘要 |
PURPOSE:To prevent instantaneous switching at the time of emergency by detecting a transversal current, which occurs upon periodical application of firing signals on a thyristor switch, and deciding an abnormal thyristor switch and accessories thereof based on thus detected transversal current. CONSTITUTION:If a thyristor 7a or a gate circuit 7b in a thyristor switch 71 is abnormal due to some cause, the thyristor 7a is not fired even upon occurrence of a TEST signal. In other words, concurrent power supply state of a normal power supply 1 and a standby, power supply 2 does not happen. Consequently, transversal current does not flow between the normal power supply 1 and the standby power supply 2, and a current detector 12 arranged on the side of the standby power supply 2 detects no current. As a result, a comparator 13 has an output of logical '0' and an indicator 16 indicates 'abnormal'. |
