The UOA Series Single Phase Under Voltage Monitoring Relay from the ATC Diversified Electronics division of Marsh Bellofram is a family of single phase voltage monitoring relays, designed to ensure the cost-effective reliable protection of critical equipment that is required to continuously operate above a certain voltage minimum, with the ability to monitor voltage levels up to 240 VAC.
Design of the UOA series ensures that when operating voltage is applied above the preset pick-up voltage, the internal relay will energize. When the voltage falls below the preset drop-out voltage for a period longer than the release delay, the output relay will de-energize. When line conditions return above the preset pick-up voltage, the UOA Series automatically resets and the internal relay energizes. The hysteresis integral to each series unit provides a differential between pick-up and drop-out trip points.