The Siemens SIRIUS 3RT2037-1AH04 is a size S2 power contactor rated for 65 A at 480 V in AC-3 duty — the motor-switching rating that governs real load handling. Screw-type terminals on the magnet coil and main contacts, with a 55 mm wide footprint that snaps onto 35 mm DIN rail per DIN EN 60715.
What the ratings mean for fit
The 65 A AC-3 rating at 480 V is the figure that decides whether this contactor handles a given motor load — AC-3 covers starting and disconnecting of squirrel-cage motors under full load. At 400 V the rated current drops to 3 A, so the 480 V figure is the high-side capability; at lower voltages the contactor carries higher currents. Size S2 means it fits the standard SIRIUS frame, so auxiliary blocks, overload relays, and busbar systems from the same S2 family mate directly without adapters.
Mounting and panel integration
Mounts by screw or snap-on onto 35 mm DIN rail according to DIN EN 60715. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so it fits tight enclosures without derating. Clearance: 10 mm upwards, forwards, and downwards; 6 mm at the sides. Depth is 174 mm, which is the dimension to watch when laying out gland plates or door clearance.