What it is and what it does
The Siemens SIRIUS 3RT1054-2AU36 is a Size S6 power contactor built for switching motor loads and resistive circuits in industrial control panels. It's rated for up to 1000 operating cycles per hour in AC-3 duty (full motor switching), which matches the pace of a conveyor line or pump station where the contactor cycles every few seconds. The spring-type terminals on the magnet coil mean no tool is needed for the control wiring — a field-friendly detail when you're replacing one on the fly. The auxiliary contact block handles 10 A at 24 V and 2 A at 48/60/110 V (–), so it can directly drive a PLC input or a small relay without an interposing stage. That saves a DIN rail slot and keeps the wiring tidy.
Where it fits and how it mounts
The contactor measures 172 mm high by 120 mm wide by 170 mm deep. It fixes to the panel with a single 9 mm screw hole. The mounting position is flexible: vertical surface, rotatable ±90°, and tiltable ±22.5° front-to-back. That helps when the panel layout is tight and you need to angle the contactor to clear a busbar or another device. Clearance requirements are modest — 10 mm upwards, 10 mm downwards, 10 mm to the side, and 20 mm forwards. That leaves room for cooling and wiring access without wasting panel depth.
What the ratings mean for your panel
The AC-3 switching rate of 1000 operations per hour is the number that governs real motor duty — it's the full-load make-and-break rating, not the lighter AC-1 resistive rate. If your application cycles faster than once every 3.6 seconds, you'll need to step up to a larger frame or add a soft starter. The AC-4 rate (130 ops/h) is for plugging and inching, where the contactor breaks locked-rotor current — that's a tougher duty, and the lower number reflects it. Operating temperature spans -25 to +60 °C, storage from -55 to +80 °C. That covers most indoor panel environments, including unventilated enclosures near process heat. The arcing time of 10–15 ms and total opening time of 40–60 ms are consistent with a standard electromechanical contactor — fast enough for motor protection coordination, but not a semiconductor-grade speed.