| 摘要 |
<p>PURPOSE:To shorten the time of an inspection by judging the commutation failure of a main thyristor or the disconnection of a fuse on the basis of output signals of a fuse disconnection detector and a thyristor voltage detector. CONSTITUTION:A fuse disconnection detector 4 connected between a fuse F and a motor 1 outputs an ''L'' level when the fuse F is disconnected. A thyristor voltage detector 5 outputs an ''L'' level when a main thyristor SM is ON. A controller 6 judges whether it is a fuse disconnection, a commutation failure or a commutation failure and fuse disconnection under the conditions that the outputs of the detectors 4, 5 are ''L'' only during the operating time of a timer 63 or not, and applies a control signal to a display unit 7 and an operation unit 8 of a direction switching contactor.</p> |
