The Siemens SIRIUS 3RT1024-1AN24 is a Size S0 power contactor rated for motor loads up to 7.5 kW at 690 V and 7.5 kW at 500 V. It handles AC-2 duty at 5.5 kW at 400 V and AC-4 switching at 12.5 A at 400 V — that covers reversing or inching applications where the contacts break full motor current. Snaps onto 35 mm DIN rail per EN 50022 (screw and snap-on mounting) and measures 45 mm wide by 85 mm tall by 140 mm deep — fits a standard panel footprint with room for side-by-side mounting.
Duty ratings and coordination
The AC-2 rating (5.5 kW at 400 V) suits slip-ring motor starting where the contactor makes and breaks the rotor circuit under reduced current. The AC-4 rating (12.5 A at 400 V) covers plugging and inching — the contacts see full locked-rotor current each cycle, so this number is the one to watch for high-cycle reversing applications. Type 2 coordination requires a 25 A gL/gG fuse upstream; Type 1 coordination allows a 63 A gL/gG fuse. Pick the coordination class based on whether you want the contactor to survive a short-circuit fault (Type 2) or accept replacement after a fault (Type 1).
Termination and environment
Main and auxiliary circuits use screw-type terminals. Main terminals accept 2x (1... 2.5 mm²) solid/stranded or up to 2x 10 mm² max; auxiliary terminals accept 2x (0.5... 1.5 mm²) solid up to 2x (0.75... 4 mm²) max. AWG equivalents: main 2x (16... 12) or 1x 8; aux 2x (20... 16) or 1x 12. Rated for pollution degree 3 (industrial environment with conductive or dry non-conductive pollution). Front face is IP20 (finger-safe), terminal area is IP00. Operating temperature range -25 °C to +60 °C.