Siemens 3UG4513-1BR20 Analog Monitoring Relay

Siemens SIRIUS 3UG4513-1BR20 Analog Monitoring Relay is a DIN-rail mounted relay in the SIRIUS 3UG4 family that provides phase‑failure, phase‑sequence, asymmetry, and undervoltage monitoring for three‑phase electrical networks. It accepts 3×160–690 V AC as the monitored line voltage, features an analog setting to tailor thresholds, and uses two changeover contacts (DPDT) with screw terminals for reliable panel wiring. The device specifies a fixed undervoltage asymmetry of 20% and a fixed hysteresis of 5%, with an adjustable delay time from 0 to 20 seconds to suit control sequences; the enclosure is IP20 protected. Siemens catalogs also note the 3UG4513-1BR20’s role in phase monitoring and indicate a recommended successor, 3UG5514-1BR20, ensuring continuity within the Sirius line. Typical applications include protecting motors, pumps, and other three‑phase loads by signaling on phase loss, incorrect phase sequence, or undervoltage, enabling protective actions in control circuits.