Design and Implementation of Auto-Phase Selector from Three-Phase Supply.

The power interruption in distribution system is about 70% for single-phase faults, while other two phases are in normal condition. In any commercial power supply system, if three phases are available, then automatic phase selection can be done in critical loads in the event of power failure in any phase. There is no need for backup power supply, and the phase is changed automatically within a few seconds. The aim of this paper is to develop an automatic phase changing switch for 220 V-240 V alternating current. The designs available are single-phase change over switches, two-phase automatic transfer switch and three-phase automatic change over switch which are manually operated. But the paper presents automatic-phase selection using electronic circuit, which is designed only for three-phase AC input power to singlephase AC output applications. [ABSTRACT FROM AUTHOR]