| 摘要 |
PURPOSE:To restore a device without sending any person to the site of the device by disconnecting a main circuit and, at the same time, evaluating an input voltage when an overvoltage is inputted and, when the input voltage drops within a prescribed period of time, automatically restoring the device. CONSTITUTION:When the voltage 101 inputted from a power source 1 exceeds a preset fixed level at the input terminal of an overvoltage protective circuit 2, the circuit 2 discontinues the output to a main circuit 3 by turning off the switch of its own circuit and, at the same time, sends a discontinuing signal 102 to an overvoltage evaluation circuit 4. The circuit 4 starts its own timer set to fixed time by using the signal 102 as a reference and evaluates the input voltage 101 during the set period. When the voltage 101 drops during the set period, the circuit 4 sends a restoring signal 103. Upon receiving the signal 103, the overvoltage protective circuit 2 again turns on the switch and supplies electric power to the main circuit 3. As a result, the main device is automatically restored. |
