SIRIUS S2 power contactor — what the ratings mean for your panel
The Siemens 3RT1036-1AM20-0UA0 is a SIRIUS-branded power contactor in the S2 frame size, designed for switching motor loads in control panels. Its AC-2 rating of 22 kW at 400 V covers wound-rotor motors and slip-ring applications where the contactor makes and breaks the rotor circuit under load. For standard squirrel-cage motors (AC-3 duty), it handles 30 kW at 500 V, which is the rating that governs most conveyor, pump, and fan starts. The AC-4 rating of 11.4 kW at 690 V applies to plugging and inching duty — frequent reversals or jogging that stress the contacts harder than a normal start. The contactor mounts via screw and snap-on onto a 35 mm standard mounting rail per DIN EN 50022, so it integrates directly into a DIN-rail panel without a separate base plate. Side-by-side mounting is permitted, which keeps the row width tight when ganging multiple contactors for multi-motor sections. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C — the storage limit governs handling during shipping and warehouse hold, not running conditions. The front face carries IP20 protection (finger-safe), while the terminals themselves are IP00, meaning the wiring compartment is not sealed against dust ingress and requires enclosure protection in dirty environments.
Termination and wiring — screw-type main terminals
The main current circuit uses screw-type terminals. Solid conductors accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or a maximum of 2x (0.75 to 4 mm²). Stranded conductors go up to 2x (0.75 to 25 mm²). The auxiliary/control circuit accepts 2x (0.75 to 16 mm²) solid or stranded. This range covers standard panel wire from 18 AWG up to 4 AWG for the power legs, so no special lugging is needed for most motor branch circuits up to the contactor's rating.