The Siemens 3UG4617-2CR20 is a SIRIUS network monitoring relay — a phase monitoring relay with digital setting and an LCD display. It monitors three-phase AC supplies for phase loss, phase sequence, asymmetry, and overvoltage, with a rated voltage range of 160 to 690 V at 50 or 60 Hz. The output contacts are rated 3 A at 250 V and 400 V (50/60 Hz), with lower ratings for DC loads: 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V. That means the relay can switch small motor starters or signal lamps directly, but for larger contactor coils you'd want an interposing relay. Asymmetry detection and overvoltage detection are built in, with a configurable auto-reset function. The LCD gives you a local readout of the measured values and settings — no separate display module needed.
The housing is 22.5 mm wide, 94 mm high, and 91 mm deep — a standard single-module width for DIN-rail enclosures. Clearance around the unit: 0 mm on all sides (up, down, forwards, backwards, sideways), meaning it can be packed tight against other devices without derating.