The Siemens SIRIUS 3UG4511-2BQ20 is a single-function phase monitoring relay for three-phase AC systems. The output relay switches up to 3 A at 250 V or 400 V (50/60 Hz), and 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V — enough to signal a PLC input or drop out a contactor coil. Auto-reset is standard, with a 2-second delayed switching to ride through brief dips. Housed in a 22.5 mm wide, 94 mm tall, 91 mm deep enclosure (IP20), it snaps onto a DIN rail in any orientation. The screw terminals accept 2 x 24-16 AWG solid or stranded wire.
The 22.5 mm width means it takes one standard module slot — plan for side-by-side spacing with other SIRIUS relays or contactors. Terminals accept 0.2-2.5 mm² (24-16 AWG) solid or stranded, strip length 8-10 mm. The LED display confirms relay status at a glance.