| 摘要 |
PURPOSE:To avoid a burning accident of a regenerative resistor even if a power semiconductor is troubled by providing a trouble deciding circuit for comparing a gate signal to the semiconductor with a conduction signal by a current detector to control start of conduction of a thyristor switch. CONSTITUTION:When a resistance regeneration is normally conducted, a power semiconductor 12 operates in response to a gate signal from a gate signal generator 11. If a current flows from the generator 11 to the resistor even if the gate signal is not output from the generator 11, a power semiconductor trouble deciding circuit 14 decides a trouble of the semiconductor, and outputs a trigger signal to a thyristor switch 15. When the switch 15 is closed, a melting current to a fuse 16 flows to melt the fuse 16, thereby breaking a regenerative resistance circuit. Thus, a burning accident of the resistor can be not only avoided, but also the resistance circuit is disconnected to operate at the time of an emergency by utilizing a power running circuit. |
