Study on AC Contactor Performance UnderVoltage Sags

AC contactor many found in industrial sectors. It function is to link induction motorto utility supply and recognicedsusceptible to voltage sags. The contactorconsist of primary and auxiliary contacts. The primary contact can opened if it is supplied by voltage sags. In an industry, a contactor is used to keep electric motors abruptly restart when the voltage sag return to normal. This studydiscussesbehaviour of three contactors caused byvoltage sags and interruption.The contactors are fabricated from distinct manufactures. Voltage sag characteristics used are sag magnitude, sag duration and also point on wave (POW) of sag initiation. The testing results show that the contactors performances are greatly influenced by them. The contactors are more susceptiblewhen theywere served with deeper and longer voltage sag. Susceptiblity of contactors to sag durationis rise when they were supplied by voltage sags with the POW near to 90o. The contactors susceptibities decrease when thesag occurs at three POWs which are0o, 45oand90o.