What It Is and Where It Goes
The Siemens SIRIUS 3RT2037-1NP30 is a S2-size power contactor. It mounts on a 35 mm DIN rail per DIN EN 60715, with screw and snap-on fastening. The coil accepts 175...280 VAC. Rated for operating temperatures from -25 to +60 °C, it handles the heat inside a packed panel without derating. Storage range goes from -55 to +80 °C, meaning it survives a hot truck ride in summer or a cold warehouse in winter.
Key Ratings and What They Mean for Your Panel
The 3RT2037-1NP30 is rated for 800 switching cycles per hour at AC-1 (resistive loads) and 700 cycles per hour at AC-3 (standard motor starting). For heavy-duty jogging or plugging (AC-4 duty), it still manages 200 cycles per hour — enough for most reversing or inching applications on a conveyor or pump line. Coil inrush current peaks at 5 A, then settles to 2 VA at 50 or 60 Hz. That's a light load on a PLC output or control relay, so you don't need a dedicated interposing relay unless you're running a dozen of these off one transformer. Dimensions are 114 mm high, 55 mm wide, and 130 mm deep. The 55 mm width — three standard 18 mm module spaces — means it fits neatly on a DIN rail without crowding adjacent devices. Clearance requirements are 10 mm upwards, forwards, and downwards, with 6 mm at the sides, so you can pack it in a row without leaving a full module gap between contactors. The auxiliary switch is built in, so you don't need a separate add-on block for basic status feedback to the PLC. Main contacts are rated for 18 A at the listed voltage range, with a 1.1 full-scale factor for short-duration overloads.