The Siemens 3RB2036-1UB0 is a SIRIUS solid-state overload relay for three-phase motor protection. It mounts directly onto a contactor (fastening method: contactor mounting), so it becomes a single assembly on the DIN rail, saving panel space and wiring.
The main circuit accepts solid wire from 0.5 to 4 mm² (single) or 2× (0.5 to 2.5 mm²), and stranded up to 25 mm² — that covers most motor leads up to about 7.5 kW at 400 V. Auxiliary contact ratings are given at multiple voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V — these are the switching limits for the signal contacts feeding the PLC or safety circuit. Surge voltage resistance is 6 kV, and burst immunity meets IEC 61000-4-4 severity level 3: 2 kV on power ports, 1 kV on signal ports. That means it will hold up in a noisy industrial panel without false trips.
Where you'd use this — ATEX and environment
This overload relay carries ATEX approval PTB 06 ATEX 3001 Ex II (2) GD, so it's suitable for use in potentially explosive atmospheres — typically Zone 1 or 2 gas, or Zone 21/22 dust, when paired with an appropriate contactor and enclosure. Shock resistance is 15 g for 11 ms. Clearance: zero mm upwards, forwards, and backwards; 6 mm at the side. Depth is 109 mm, width 55 mm, height 92 mm.