What it is and what it does
The Siemens SIRIUS 3RT5056-6AP36-0TH0 is a size S6 power contactor rated for AC-3 duty at 90 kW on a 400 V three-phase line. That rating governs switching of standard squirrel-cage induction motors — pumps, conveyors, fans — where the load current is made and broken infrequently during normal operation. The 90 kW figure at 400 V is the motor power the contactor can handle under those conditions, so it directly sizes the part to the motor nameplate. The coil accepts 220 to 240 V AC or DC, simplifying panel wiring where a single control voltage feeds both AC and DC loads. The contactor carries 2 NO and 2 NC auxiliary contacts built in, enough for basic feedback and interlocking without an add-on block.
Where it fits in the panel
Size S6 means a larger frame — bar connections for the main power circuit, not spring terminals. This contactor is designed for screw-type connections on both main and auxiliary circuits, so expect to land lugs or bus bars on the power side. Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022, same as the rest of the SIRIUS family, but the S6 footprint needs more horizontal space than the S0 or S2 sizes. Plan for 6 mm side clearance to grounded parts.
Lifecycle and sourcing reality
For a BOM freeze or a line-down replacement, this contactor can be specified directly. Sourcing is through normal Siemens supply — quoted to order against an RFQ. No second-source or cross-reference is documented from the manufacturer, so the 3RT5056-6AP36-0TH0 is the direct fit for any panel designed around a size S6 SIRIUS contactor with a 220-240 V coil.