... microcomputer, is soft pieces of hardware and the compound. Work according to the characteristics of the three-phase ac sequence ... low malfunction, service, etc. In stead of touch, thyristor switch, common compound switch, widely used in low voltage reactive power claims.2 ... 20%, use life 100,000 times.2. Switch 2000V switch power voltage: acuities than 2W3. Switch pressure resistance than 0.1V: 20S, ...