| 摘要 |
<p>PURPOSE:To improve the safety and reliability of a DC power equipment by inhibiting leakage currents even when the capacitance of the constant voltage element of a surge voltage absorbing circuit is set at a large value or even when the constant voltage element is short-circuited by the surge voltage. CONSTITUTION:The series circuit of arresters 10, 11 (first constant voltage elements) is operated to surge voltage at a normal mode applied between the line H and line N of an AC power 1 and the series circuits of the arrester 10 or 11 and a varister 12 (a second constant voltage element) and a capacitor 13 (a leakage current suppressing element) to surge voltage at a common mode applied between the line H or the line N and a frame ground FG respectively, thus absorbing surge voltage. Breakdown strength properties and power capacitance are increased because the two constant voltage elements are operated in series in both surge voltage while no leakage current flows through the frame ground FG even when either of them is short-circuited, and the capacitor 13 inhibits leakage currents when both surge voltage are short-circuited, thus preventing the possibility of an electric shock.</p> |
