Siemens 3UG4512-1AR20 Analog Monitoring Relay

Siemens 3UG4512-1AR20 Analog Monitoring Relay is a SIRIUS phase‑monitoring device for three‑phase power systems that continuously checks for phase loss and proper sequencing on 3 x 160–690 V AC lines at 50/60 Hz, delivering a single SPDT changeover contact via screw terminals for signaling. Built for DIN rail mounting with IP20 protection, it supports auto‑reset and offers robust mechanical endurance up to 10,000,000 switching cycles and electrical endurance up to 100,000 cycles at AC‑15 (230 V). The thermal current of the switching element is rated up to 5 A, making it suitable for small control circuits. Detection capabilities include phase failure detection and phase sequence recognition; undervoltage/overvoltage detection and asymmetry detection are not included. Surge immunity is specified up to 6 kV, contributing to reliability in demanding panel environments. Note: this model is documented as the predecessor to Siemens 3UG5512-1AR20, the preferred successor, reflecting ongoing product evolution while preserving core monitoring functions.