What it is and what it does
The Siemens 3UG4841-2CA40 is a SIRIUS active power monitoring relay with a digital setting for cos phi monitoring. It measures current from 0.2 to 10 A and provides a relay output rated 3 A at 250 V or 400 V, 50/60 Hz. The LCD display shows the measured power factor, and the unit snaps onto a DIN rail (22.5 mm wide, 103 mm tall, 91 mm deep). The relay output is rated 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V for DC loads, so it can switch small DC control signals directly. The IP20 protection class means it is suitable for installation inside a closed control cabinet only.
Mounting and environment
Snap-on mounting to a 35 mm DIN rail; the 22.5 mm width fits standard terminal-block spacing. Mounting position is any, which simplifies panel layout. Operating temperature range is -25 to +60 °C, storage and transport -40 to +85 °C. Wire connections accept solid 24–16 AWG or stranded 20–14 AWG. The relay supports external reset and has electrical isolation between the outputs.