SIRIUS S0 power contactor — 3RT1024-3AF06
The Siemens SIRIUS 3RT1024-3AF06 is a Size S0 power contactor with three normally-open main contacts and no normally-closed main contacts, rated for motor switching up to 7.5 kW at both 500 V and 690 V. It carries an AC-4 rating of 12.5 A at 400 V, meaning it can handle the demanding inrush and breaking duty of reversing or plugging motor loads — not just steady-state running current. The screw-type terminals accept 2x (0.25... 2.5 mm²) solid or 2x (1... 2.5 mm²) stranded conductors, with a maximum of 2x 10 mm² per terminal, which covers most panel wiring up to the 25 A gL/gG fuse required for Type 2 coordination.
DIN-rail panel integration
The 65 mm width and 85 mm height place it in the S0 footprint, which is the standard frame size for contactors in the 7.5 kW range. Depth is 91 mm — verify clearance to the gland plate or back panel if the enclosure is shallow. Side-by-side mounting is allowed, so a row of these contactors can be ganged without thermal gaps, saving rail space in multi-motor panels.
Switching ratings and coordination
For AC-2 duty (slip-ring motor starting) at 400 V, the rated power is 5.5 kW. The AC-4 rating of 12.5 A at 400 V governs the most severe switching duty — reversing, inching, or plugging — where the contactor must break the locked-rotor current. For Type 2 coordination (no-weld fault protection), the required upstream fuse is 25 A gL/gG; for Type 1 coordination (welding permitted), the fuse can be 63 A gL/gG.