SIRIUS Size S2 power contactor — 65 A at 480 V, spring terminals
The Siemens 3RT2037-3AF04 is a SIRIUS-branded power contactor in the Size S2 frame, rated for 65 A at 480 V in AC-3 duty — the motor-switching current that governs real-world sizing for induction motors up to 10 hp at 230 V. The coil connection uses spring-type terminals, which cuts wiring time versus screw-clamp on the control side; main power terminals accept 2x (0.5 … 2.5 mm²) solid or stranded conductors. Mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 60715, with ±180° rotation possible on a vertical surface and ±22.5° tilt forward/backward — useful when panel layout forces an unconventional orientation.
Duty-cycle limits and switching frequency
Maximum switching frequency depends on the utilization category: 800 cycles/hour in AC-1 (resistive loads), 700/h in AC-3 and AC-3e (standard motor starts), 400/h in AC-2 (slip-ring motor), and 200/h in AC-4 (plugging/inching). Arcing time spans 10 to 20 ms, with a make-time of 10 to 18 ms at rated AC — these numbers matter for coordination with upstream short-circuit protection devices.
Clearance and mounting position
Minimum clearances to adjacent metalwork: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm at the side — essential to account for when packing multiple contactors on a DIN rail inside a crowded enclosure. The contactor can be mounted in any orientation within ±180° rotation on a vertical surface and ±22.5° tilt, which simplifies integration into existing panel layouts without custom brackets.
Environmental and mechanical ratings
Operating temperature range is -25 to +60 °C during operation, with storage from -55 to +80 °C — the wider storage window covers handling and shipping, not running conditions. Mechanical life is rated at 10 million cycles typical, which aligns with the SIRIUS S2 family's expected endurance for high-cycle applications like conveyor or pump control.
Dimensions and auxiliary contacts
Dimensions: 114 mm height, 55 mm width, 178 mm depth — the 55 mm width matches the standard S2 footprint, fitting two units per 110 mm DIN-rail section.