The Siemens 3RT2038-3AC20 is a SIRIUS S2 power contactor rated for 65 A in AC-3 duty at 480 V, making it suitable for switching three-phase motor loads up to that current in industrial control panels. The coil is wound for 24 V at 50 Hz (drawing 0.36 A at 50 Hz, 0.39 A at 60 Hz), so it pulls in cleanly on a standard 24 VAC control transformer.
Fastening is by screw or snap-on onto 35 mm DIN rail per DIN EN 60715, with a mounting position that allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward — useful when the panel layout forces an unconventional orientation. Physical footprint is 55 mm wide, 114 mm high, 130 mm deep; clearance requirements are 10 mm upwards, forwards, and downwards, and 6 mm at the sides.
Auxiliary contacts and switching performance
The contactor carries an auxiliary switch block with 1 NO + 1 NC configuration (18…1 main contacts), letting it signal status back to a PLC or interlock a downstream device without a separate add-on module. Switching frequency ranges from 700 operations/hour at AC-1 (resistive) down to 150 ops/hour at AC-4 (plugging/reversing), with AC-3 motor duty rated at 500 ops/hour — match the duty cycle to your application to avoid overheating the coil or contacts.