S6 Frame, 200-277 V Coil — What Fits
The Siemens 3RT1056-6SP36 is a SIRIUS power contactor in the S6 frame size, designed for switching motor loads and resistive loads in industrial control panels. The coil is rated for 200-277 V AC at 50/60 Hz, with a pick-up threshold of 0.8 × rated value and a 1.1 × full-scale overvoltage limit — so it pulls in reliably on a nominal 240 V line and stays sealed through a 10 % brownout. The 170 mm depth, 120 mm width, and 172 mm height define the panel footprint. Mounting is by screw fixing through a single 9 mm hole — not DIN-rail snap-on — so budget panel drilling time and a dedicated backplate location.
Duty-Cycle Ceilings and Wiring Reality
The maximum switching rate depends on the duty category: 750 operations per hour in AC-1 (resistive) and AC-3 (squirrel-cage motor starting), 300 per hour in AC-2 (slip-ring motor), and 130 per hour in AC-4 (plugging / inching). The AC-3e rating also caps at 750 per hour — the same ceiling as standard AC-3, so no speed penalty for the energy-efficient motor variant. Power wiring accepts stranded conductors from 25 to 120 mm² — that covers everything from a 50 A feed to a 250 A motor circuit on the same lug range. The auxiliary circuit terminals handle 2 × (0.5-1.5 mm²) solid or 2 × (0.75-2.5 mm²) stranded, with a max of 2 × (0.75-4 mm²) — enough for daisy-chaining control power through the auxiliary contacts. Mechanical life is 10 million operations typical. The MTBF is listed at 75 years — a reliability figure that assumes the contactor is operated within its rated duty cycle and ambient temperature range (-25 to +60 °C operating, -55 to +80 °C storage).
Mounting and Clearance Constraints
The mounting position allows a vertical surface with +/-90° rotation and +/-22.5° tilt front-to-back — so it can be oriented on a panel door or a 90-degree bracket without derating. Minimum clearances to adjacent metalwork: 10 mm upwards, 10 mm downwards, 10 mm at the sides, and 20 mm forwards for arc-chamber venting. Arcing time is 10-15 ms, and the total operate time (AC or DC) is 115-130 ms — consistent with a contactor this size. The coil is terminated via screw-type terminals, not fast-on tabs, so expect a screwdriver termination on the control wiring.
Lifecycle and Sourcing
The lifecycle stage is marked as current production — the 3RT1056-6SP36 is an active catalog item from Siemens.