The Siemens 3RU2146-4MD0 is a SIRIUS thermal overload relay — Size S3, CLASS 10 trip curve, rated 45 kW at 400 V in AC-3e duty. It mounts directly to a contactor via the M8 fastening method, so it's a straight swap on a contactor that's already panel-wired.
Contactor mounting (M8) keeps the relay directly coupled to the contactor — no separate DIN-rail footprint needed. The S3 frame carries screw-type terminals on the main circuit, accepting solid 2x (2.5…16 mm²) and stranded up to 1x (10…70 mm²). Any mounting position works. Depth is 125 mm, width 70 mm, height 105 mm — fits within the contactor's own envelope, so panel fill factor doesn't change when you add it.
Auxiliary contacts are rated across a wide voltage range: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and 0.75 A at 690 V. That covers most control-circuit voltages in a 400 V panel.