Description
The HRN3-80 is a 3-phase voltage monitoring relay that protects connected equipment by monitoring undervoltage, phase loss, phase sequence, and phase asymmetry in 3-phase networks. Unlike fixed-range monitoring relays, the HRN3-80 offers a selectable monitoring range across a wide 208–480 V AC window, and its lower voltage threshold (Umin) is set as a percentage (80–95% of Un) of the selected range — making it adaptable to a variety of supply voltages commonly found across different installations and regions.
The relay is self-powered directly from the monitored circuit, eliminating the need for a separate control supply. It measures true RMS voltage for accurate monitoring even under distorted waveforms, and features an adjustable time delay (0.3–30 s) to ride through brief voltage dips without nuisance tripping. Phase asymmetry monitoring is adjustable (2–10% of Un) and can be switched off entirely if not required. Clear LED indication on the front panel shows supply status and fault conditions, making diagnostics straightforward for panel builders and maintenance technicians protecting motors, pumps, and other 3-phase loads from voltage-related damage.