Phase Reversal Monitoring Outline · [ Standard ] · Linear+

[BOBGCF]

One of our customers builds portable vacuum equipment. The problem they have is not knowing if receptacle are all phased correctly. They install a change-over contactor (reversing contactor) in order to get correct rotation of the blower motor. There are situations which incorrect phase will cause the vacuum to become a blower and create the discharge of material requiring a cleanup. Bumping or quick on-off of the unit is not acceptible in some applications. Would phase monitoring relays work in this application. How exactly do phase monitoring relays work. When power is lost, as in disconnecting a plug are you starting at square one with the relay. Their equipment runs on 460V and also 380/400 V.

Regards,
Bob Berger
GCF Inc.

[John Williams]

An MWG series, part no. 84 873 022, phase monitoring relay could be used for your application. This model monitors phase sequence and failure. If the sequence is correct, the output relay is energized. This model can operate on 3 phase circuites from 208 to 480 VAC.

Other models will also monitor voltage or phase imbalance.