| 摘要 |
PURPOSE:To prevent a breaker from becoming impossible to be cutoff by stopping the operation of a chopper, delaying the time in consideration of the time constant of a main circuit and turning the breaker OFF. CONSTITUTION:When a notch-off command is emitted from a notch-off command circuit 21, a command diaphragming the currents of a main motor is outputted from a current diaphragming circuit 22, and currents are diaphragmed until currents reach 0. A chopper 10 is turned OFF. On the other hand, the off command of the chopper 10 is added to a timer circuit 23 having the time element of approximately treble as large as the time constant of a main circuit, and delayed for a fixed time, and commands turning breakers 3, 6 OFF are outputted. Accordingly, the breakers can be no-current interrupted, and the titled device is released from the impossible accident of the cutoff of small currents.
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