The Siemens SIRIUS 3UG3013-1BR60 is a 45 mm monitoring relay dedicated to three-phase voltage supervision with undervoltage detection. It monitors AC supplies in the range 3x 380...550 V at 50/60 Hz and terminates via screw terminals.
The 380...550 V AC range covers the common European 400 V and 480 V industrial networks. The relay detects undervoltage conditions on all three phases, which is the typical trigger for motor protection or load shedding in a distribution panel. Screw terminals simplify field wiring for panel builders and maintenance crews — no special crimping tool required. The relay is self-powered from the monitored lines, so no auxiliary supply is needed.