The Siemens 3RB3036-2WD0 is a SIRIUS solid-state overload relay, S2 frame size, designed for contactor mounting. Its CLASS 20E trip curve gives a 20-second maximum trip time at 7.2× rated current — the standard choice for standard-start induction motors driving pumps, fans, and conveyors where the acceleration time stays under 10 seconds. Rated thermal current (Ith) is 60 A continuous, and that same 60 A holds at both 480 V and 600 V, so no derating between common North American line voltages. The main circuit accepts screw-type terminals sized for M6 ring lugs, with stranded wire capacity up to 2×(10…35 mm²) or a single 50 mm².
Auxiliary contact ratings and wiring
The integrated auxiliary switch (N/C + N/O, wired to terminals 95/96 and 97/98) carries a range of control-circuit voltages. At 24 V it switches 2 A; at 120 V it handles 4 A; at 230 V it is rated 3 A. Lower-voltage DC ratings are also listed: 0.55 A at 60 V, 0.3 A at 110/125 V, and 0.11 A at 220 V. The solid-state design means no mechanical contacts to pit or weld, so the trip signal stays reliable even after repeated overload events. Wiring to the auxiliary terminals accepts solid or stranded conductors: 2×(0.25…1.5 mm²) per clamp. The screwdriver spec calls for a Pozidriv PZ2 tip with shaft diameter 5–6 mm — standard across the SIRIUS family, so no special tool needed on the panel bench.
Mounts directly onto the contactor via the fastening method listed as "contactor mounting" — no DIN rail bracket required, which saves a slot in a crowded panel. The S2 footprint is 55 mm wide × 99 mm high × 104 mm deep, and the relay can be installed in any orientation. Operating ambient range is -25…+60 °C with full temperature compensation over that span, so it tracks motor heating accurately even near a warm drive or in a non-conditioned cabinet. Storage and transport range extends to -40…+80 °C. Shock resistance is 15 g / 11 ms; vibration tested to 1–6 Hz at 15 mm amplitude and 6–500 Hz at 20 m/s² for 10 cycles.