The Siemens 3RU1136-4EB1 is a SIRIUS thermal overload relay, Size S2, with CLASS 10 trip characteristic. It protects motors against overload and phase failure, and is ATEX certified (DMT 98 ATEX G 001) for use in potentially explosive atmospheres.
If your motor has a long acceleration time (high-inertia loads like centrifuges), you'd need CLASS 20 or 30; this part is not for that. Size S2 covers the mid-range of the SIRIUS overload family, typically paired with contactors in the 9–38 A range (check your motor FLA against the relay's setting range, which is not listed here but is standard for S2). Auxiliary contact ratings are given for multiple voltages: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V — these are the switching capacities for the signal side, not the main power path. The main circuit uses screw-type terminals accepting stranded wire up to 35 mm² or 2× 25 mm²; auxiliary terminals accept up to 2.5 mm² solid or stranded. That's generous for a relay of this size — no need for terminal adapters on typical control wiring. Power dissipation per pole is 4.6 W. The relay is rated for 100 % relative humidity during operation.
Mounting is stand-alone installation — not DIN rail snap-on. The relay is designed for screw fixing directly to a mounting plate or panel. That means you can butt it against other components on three sides, but leave 6 mm side gap for airflow and wiring access. Dimensions: 105 mm high, 55 mm wide, 118 mm deep.
Shock resistance is 8g for 10 ms — suitable for industrial machinery but not for high-vibration applications like crushers or engines without additional damping. Surge voltage resistance rated at 6 kV, which covers installation category III in most industrial environments.