What this SIRIUS power contactor is and what it does
The Siemens 3RT1056-6SF36-3PA0 is a SIRIUS power contactor in the S6 frame size, designed for switching motor loads and resistive loads in industrial control panels. It carries a coil rated at 96-127 V AC, with screw-type coil terminals and an integrated auxiliary switch. The contactor mounts via screw fixing to a vertical surface, with ±90° rotation and ±22.5° tilt adjustment for panel layout flexibility. Rated mechanical endurance is 10,000,000 cycles typical, with an MTBF of 75 a. The main power circuit accepts stranded conductors from 25 to 120 mm²; the auxiliary circuit accepts solid or stranded wire up to 4 mm². Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C.
Key ratings and what they mean for your panel
Switching frequency varies by duty class: AC-1 (resistive) and AC-3 (motor start/run) both allow up to 750 operations per hour, AC-2 (slip-ring motor) also 300/h, and AC-4 (plugging/inching) drops to 130/h. The AC-3e maximum matches the standard AC-3 rate at 750/h. These rates define the thermal cycling the contactor can sustain without accelerated wear — a conveyor running frequent start/stop cycles at 750/h stays within the AC-3 envelope. Operate time is 115-130 ms on both AC and DC coils, with an arcing time of 10-15 ms. The coil pickup threshold is 0.8 × rated voltage, dropout at 0.6 × rated (50/60 Hz). These figures matter for control logic timing and for ensuring the contactor holds in during voltage sags. Auxiliary contact ratings: 10 A at 24 V, 2 A at 48 V, 2 A at 60 V. The auxiliary switch is built in, so no separate add-on block is needed for basic signaling or PLC feedback.
Mounting and integration into the enclosure
Envelope dimensions: 172 mm high × 120 mm wide × 170 mm deep. Mounting is screw-fixing to a vertical surface; the contactor can be rotated ±90° and tilted ±22.5° front-to-back. Required clearances: 10 mm upward, 10 mm downward, 20 mm forward, 10 mm at the sides. These clearances govern gland-plate layout and busbar routing — a 120 mm wide contactor with side clearance needs roughly 140 mm of DIN-rail or backplate width per unit. Main power terminals accept stranded 25-120 mm² cable. Auxiliary terminals accept 2× (0.5-1.5 mm²), 2× (0.75-2.5 mm²), or max 2× (0.75-4 mm²) solid or stranded. The coil uses screw-type terminals — no push-in or spring-cage on the coil circuit. Panel builders should plan for a screwdriver-accessible coil connection.
Lifecycle and sourcing posture
Sourcing is straightforward: this is a current-catalog SIRIUS contactor. Availability and current pricing are confirmed at quote time against an RFQ. The part is quoted to order through independent distribution — no minimum-buy or long-lead concern typical of end-of-life parts.