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
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.