Manufacturing for NBV has been discontinued. As an alternative, please refer BA300 for battery monitor application.

The NBVIIA relay is a high speed sensitive three-phase voltage unbalance relay which is capable of detecting a small voltage unbalance in a three-phase system. The NBVIIA when applied as a protective device is normally used in conjunction with a time-delay relay. One NBVIIA relay and one timing relay are required at each terminal.