The Siemens 3UG4512-2AR20 is a SIRIUS phase monitoring relay designed to supervise AC three-phase systems for phase loss, phase sequence, and undervoltage or overvoltage conditions. It monitors the supply between 160 and 690 VAC at 50 or 60 Hz, with a rated operational current of 3 A at 250 V or 400 V. The relay provides a single changeover contact rated for 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V, making it suitable for signaling or direct control of smaller loads.
The 22.5 mm width fits standard 1-module spacing, and the 84 mm height with 91 mm depth leaves room for wiring in shallow enclosures.