| 摘要 |
PURPOSE:To ensure a high-accuracy measurement for the insulation resistance which no effect of the floating capacity of the earth line, by applying two low- frequency signals to the earth line and then detecting the signal component to perform the prescribed operation. CONSTITUTION:The detection part includes the low-frequency signal oscillators OSC1 and OSC2 having the angle frequencies omega1 and omega2 (omega1>omega2) and to be inserted to the earth line EL and the resistance R0 which detects the current flowing to the line EL. Thus the detecting part detects the signal components e1 and e2 of the frequencies omega1 and omega2 through the filter part, and then carries out an operation of 1/(omega2<2>e1<2>-omega1<2>e2<2>)<1/2> to obtain the insulation resistance value at the output. |
