It combines a thermal overload release (Class 10) with a magnetic short-circuit trip in a single 3-pole device, rated 45 A at 400 V AC-3 and 690 V maximum. That 45 A at 400 V AC-3 is the motor-switching rating — it handles the locked-rotor inrush and switching duty of a motor load up to that current, not just resistive heating.
The S2 frame size gives a 55 mm width, 140 mm height, 149 mm depth — that depth is the full body, so check clearance behind the rail for wiring. Main circuit connections are top and bottom, screw-type box terminals accepting 2×(0.75…25 mm²) solid/stranded or 1×(0.75…35 mm²). Torque to 3…4.5 N·m. The 20 W typical power loss at rated current matters for thermal management inside a sealed enclosure; derate if ambient exceeds 60 °C.
Rated for -20 to +60 °C operating, -50 to +80 °C transport. Withstands 25 g / 11 ms shock per IEC 60068-2-27. Installation altitude up to 2000 m. RoHS substance prohibition date 2006-07-01. Surge voltage resistance 6 kV. Humidity 10 to 95% during operation. Operating frequency at AC-3 maximum 15 operations per hour — that is the mechanical limit for the thermal reset cycle, not a continuous switching rate.