| 摘要 |
PURPOSE:To perform a series of change-over operations at high speed and at precise timing by ON-OFF controlling a thyristor switch by an ignition controlling device according to an existence of two kinds of electric potential differences. CONSTITUTION:The first voltage detecting device 12 detects an existence of an electric potential difference VSTEP between a variable contact shoe 4 and a variable contact shoe 5. The second voltage detecting device 13 detects an existence of an electric potential difference VSCR at both ends of a thyristor switch 8. An ignition controlling device 11 changes a switch 8 to an OFF state when the electric potential difference VSTEP exists and the electric potential difference VSCR does not exist. Therefore, a series of change-over operations are performed at high speed and at precise timing. |
