Siemens 3UG4512-1BR20 Analog Monitoring Relay

Siemens 3UG4512-1BR20 Analog Monitoring Relay is a three‑phase protection device that monitors phase condition to guard electrical systems against phase failure and incorrect phase sequence. Designed for 3 × 160…690 V AC operation at 50…60 Hz, it provides two changeover contacts (DPDT) for signaling and control, with screw-terminal connections for secure wiring and IP20 protection. This DIN rail‑mountable relay is part of the SIRIUS 3UG4 family and supports phase sequence recognition to help prevent motor or compressor damage in industrial apps such as motors, pumps, cranes, and other mobile equipment. Siemens’ catalog indicates this model has been superseded by the 3UG5512‑1BR20, reflecting lifecycle progression while remaining compatible with legacy installations. Overall, its compact form factor, TS 35 mm mounting compatibility, and dual outputs make it suitable for panel installations where reliable phase monitoring and reliable alarm/control signaling are required.