What this contactor is and where it fits
The Siemens 3RT2035-1AN24 is a SIRIUS power contactor in the Size S2 frame, designed for switching motor loads and resistive loads in industrial control panels. It fastens via screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715, so it integrates directly into a standard panel layout without adapters.
Key ratings and what they mean for fit
Rated at 40 A at 480 V, this contactor handles typical 3-phase motor loads up to that current in AC-3 duty — the operating current that governs real motor switching, not just resistive heating. The Size S2 frame (174 mm deep, 55 mm wide, 114 mm tall) determines the DIN-rail footprint and the clearance you need around it: 10 mm upwards, forwards, and downwards, and 6 mm at the side for arc flash and heat dissipation. Operating temperature range of -25 to +60 °C covers most indoor panel environments; storage range extends to -55 to +80 °C. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward, which gives flexibility in tight enclosures.
Switching duty and auxiliary contact capacity
Maximum switching frequency varies by duty: 1 200 cycles/hour at AC-1 (resistive), 1 000 at AC-3 (motor run), and 300 at AC-4 (plugging/inching). The main contacts are 3-pole normally open (3 NO). Auxiliary contacts are not fitted on this variant — the order code suffix indicates no built-in aux switch, so you add a separate auxiliary contact block if needed. When used for control-circuit switching, the auxiliary contact ratings are: 6 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. These are the make/break capacities for the coil or signal circuit, not the main power path.