What it is and what it does
The Siemens SIRIUS 3RT1056-6NP36-3PA0 is a size S6 power contactor designed for switching motor loads and resistive loads in industrial control panels. It uses a 200-277 V AC coil and mounts via screw fixing, not DIN rail — so plan for a drilled backplate or mounting rail with 9 mm holes on a 120 mm width footprint. Rated for continuous duty in ambient temperatures from -25 to +60 °C, with storage range from -55 to +80 °C. The mounting position is flexible: vertical surface with +/-90° rotation and +/-22.5° tilt front-to-back, which helps when fitting into tight enclosures.
Key ratings and what they mean for your panel
This contactor is built for high switching frequencies: up to 800 operations per hour in AC-1 (resistive) duty, 750 in AC-3 (motor start/run), and 130 in AC-4 (plugging/inching). The AC-3e rating matches AC-3 at 750 ops/h, so it handles frequent motor starts without derating the coil. Coil pick-up and drop-out times are 80-90 ms on both AC and DC supplies, with arcing time between 10-15 ms. That means predictable contact closure timing for sequencing logic — useful when coordinating with upstream breakers or downstream auxiliaries. The auxiliary switch (built-in) handles 10 A at 24 V, 2 A at 48 V and 60 V, and 1 A at 110 V — enough for direct PLC input or relay coil drive without an interposing relay.
Wiring and integration details
Main power terminals accept stranded cable from 25 to 120 mm² — that's a serious lug range for a size S6 frame, covering motor feeds up to roughly 200 A depending on duty. The coil uses screw-type terminals, not spring-cage, so expect to torque down properly. Auxiliary wiring is via solid or stranded conductors: 2x 0.5-1.5 mm², 2x 0.75-2.5 mm², or max 2x 0.75-4 mm² per terminal. Keep the smaller gauge for signal-level aux circuits and the larger for interposing relays. Clearance distances: 10 mm upwards, 10 mm downwards, 10 mm sideways, and 20 mm forwards from the contactor body for arc venting and airflow. That 20 mm forward clearance is often the one people miss when panel depth is tight.
Lifecycle and sourcing posture
For a BOM freeze or compliance audit, expect standard Siemens documentation: CE declaration, RoHS and REACH statements, and UL/CSA file numbers per the contactor family. No special PCN risk here.