SIRIUS size S6 power contactor — 96-127 V AC coil
The Siemens 3RT1056-6SF36 is a SIRIUS power contactor in the size S6 frame, designed for switching motor loads in industrial control panels. It carries a 96-127 V AC coil with a pickup threshold of 0.8x rated value, meaning the coil pulls in reliably at about 77 V AC and holds through the nominal range. Main power terminals accept stranded conductors from 25 up to 120 mm² — sized for the larger cable lugs common on 100+ A motor circuits. The contactor mounts on a vertical surface and can be rotated ±90° or tilted ±22.5° front-to-back, giving panel builders flexibility in tight enclosures. Operating temperature range is -25 to +60 °C, with storage tolerance from -55 to +80 °C. The MTBF is listed at 75 years — a reliability figure that reflects the expected mean time between failures under continuous rated operation, not a warranty or service-life guarantee. Switching frequency varies by duty class: up to 750 cycles/hour for AC-1, AC-3, and AC-3e loads, 300 cycles/hour for AC-2, and 130 cycles/hour for AC-4. The auxiliary switch is included as standard, with screw-type coil terminals.
Panel integration notes
The size S6 contactor measures 172 mm high, 120 mm wide, and 170 mm deep. It is fastened with screw fixing through a single 9 mm mounting hole. Clearance requirements: 10 mm upwards, 10 mm downwards, 20 mm forwards, and 10 mm at the sides. These spacings allow for heat dissipation and arc-chamber venting — the arcing time is 10-15 ms. The main power terminals accept 25-120 mm² stranded, while the auxiliary and coil terminals use screw-type connections accepting 0.5-4 mm² solid or stranded wire (dual-entry for 0.5-1.5 mm² and 0.75-2.5 mm²).