| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a switching unit for connecting a mechanical relay 4 in parallel with a voltage compensation circuit 3 supplying power to a load 20 while superposing a compensation voltage to a power supply voltage and using them while switching in which a switching is made to high speed compensation operation when the mechanical relay 4 is opened. <P>SOLUTION: An open circuit detecting circuit 21 provided between both poles of the mechanical relay 4 comprises a current source 24 connected in parallel with the mechanical relay 4, a voltage limit means 22 conductible when a predetermined voltage is exceeded, and a current detector 23 for detecting the current being conducted to the voltage limit means 22. Open circuit of the mechanical relay 4 is detected by detecting a current flowing from the current source 24 to the voltage limit means 22 when the mechanical relay 4 is opened and then a transition is made to compensation operation. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
