| 摘要 |
PURPOSE:To eliminate the power loss of a discharging resistor at the time of operating a converter by connecting a smoothing capacitor to the resistor only when the capacitor is discharged. CONSTITUTION:Since a contactor 22 is, when a power switch 12 is closed, opened and a contact 32 is closed, the rectified output from a rectifier 14 is supplied through a current limiting resistor 20 to a smoothing circuit 16. When a predetermined time is elapsed, a timer switch circuit 26 is closed to supply an exciting current to an exciting coil 24, the contactor 22 is closed and the contactor 32 is opened. When the power switch 12 is then opened, no exciting current flows through the coil 24, and accordingly the contact 22 is opened and the contact 32 is closed. Thus, a discharging resistor 30 is connected in parallel with a smoothing capacitor 28. In this manner, wasteful power consumption can be eliminated for the discharging resistor. |
