Siemens SIRIUS 3RT2037-3CL24-3MA0 — Size S2 Power Contactor
The Siemens SIRIUS 3RT2037-3CL24-3MA0 is a Size S2 power contactor rated for 65 A in AC-3 duty at 480 V — the motor-switching current that determines real-world fit for three-phase induction motors up to that load. Spring-cage terminals on the coil and main contacts accept 2x (0.5 to 2.5 mm²) solid or stranded conductors, a wiring preference for panels where vibration resistance matters over screw-clamp retention. Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, with a width of 55 mm and depth of 178 mm — check your gland-plate clearance before committing the BOM line. The mounting position is flexible: +/-180° rotation on a vertical surface, plus +/-22.5° tilt forward/backward, which simplifies fitting into crowded subpanels or angled enclosures.
Mechanical & Environmental Clearances
Minimum air clearances around the contactor: 10 mm upwards, downwards, and forwards; 6 mm at the sides. These govern how tightly you can pack multiple units on a DIN rail without forced derating. Operating temperature range is -25 to +60 °C; storage range extends to -55 to +80 °C. The storage limit governs handling during transport and off-season warehousing, not running conditions.
Switching Performance & Coil Data
Arcing time spans 10 to 20 ms; the coil's make/break duration is 10 to 18 ms at AC — relevant when coordinating contactor timing with upstream short-circuit protection devices. Maximum switching frequency varies by duty: 800 operations per hour at AC-1 (resistive), 700 at AC-3 (motor start/run), 400 at AC-2 (slip-ring motor), and 200 at AC-4 (plugging/inching). Use the AC-3e rating of 700 ops/h as the practical benchmark for standard motor starting. Mechanical life is typically 10,000,000 operations — a design-life figure that assumes proper coil suppression and within-spec switching frequency.