This is a compact microcontroller device based on latest technology. It senses the voltage supply at its terminals and operates electromagnetic relay. The Under Voltage Relay gets de-energised for under voltage conditions i.e. when any phase voltage falls below the set value and gets energised after the voltage rises above the set value plus the ON/OFF differential setting. OFF-Time delay & ON-Time Delay is available for protection against transients. Under voltage setting and time delay are continuously adjustable with the help of a knob over a linear calibrated dial. Auxillary voltage of 12V or 24VDC can be provided.