What it is and what it does
The Siemens 3RT2038-1AN20 is a SIRIUS power contactor in size S2, designed for switching motor loads and resistive loads in industrial control panels. Rated operating current hits 65 A at 480 V — that's the AC-3 motor-switching current, so it handles a 3-phase induction motor up to roughly 40 hp at 480 V without derating. Screw-type coil terminals and main contacts make it a straightforward drop-in for existing panel wiring.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 55 mm width and 114 mm height fit standard panel layout grids. Mounting position is flexible: +/-180° rotation on a vertical surface, plus +/-22.5° tilt forward/backward — useful when the panel layout forces an odd angle. Clearance: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side. That keeps the arc space and cooling path clear without over-allocating panel real estate.
Ratings and what they mean for the buyer
The headline number — 65 A at 480 V — is the AC-3 rated operating current, meaning it switches three-phase squirrel-cage motors up to that current under full load. For resistive loads (AC-1), the switching frequency can go to 700 operations per hour; for AC-3 motor duty, 500 ops/h; for AC-4 (plugging/reversing), 150 ops/h. The coil draws 0.36 A at 50 Hz and 0.39 A at 60 Hz — standard control transformer sizing. Auxiliary switch is built in, rated 10 A at 24 V, 2 A at 48/60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, 3 A at 400 V, 0.6 A at 440 V. That covers most PLC output and relay interposing needs without an add-on block.