The Siemens 3RT2037-3NB30 is a SIRIUS-brand power contactor in the S2 frame size, designed for switching motor loads and resistive circuits in industrial control panels. It mounts on 35 mm DIN rail per DIN EN 60715 via screw or snap-on fastening, so it drops into a standard panel layout without custom bracketing. The coil accepts 20-33 V AC or DC, with an inrush peak of 3 A and holding draw of 2 VA at 50 or 60 Hz. Spring-type terminals on the coil reduce wiring time — no screw torque to verify, just strip and insert. Rated switching frequency varies by duty: 800 cycles/hour for AC-1 resistive loads, 700 for AC-3 motor starting, 400 for AC-2 slip-ring motors, and 200 for AC-4 plugging/reversing. That AC-3 figure (700 1/h) tells you it handles frequent conveyor starts without overheating the coil or arc chamber.
Integration Notes
Physical envelope: 114 mm high, 55 mm wide, 130 mm deep. The depth (130 mm) is the dimension that matters most when fitting into shallow enclosures — measure your backpanel clearance before committing. Side clearance of 6 mm and vertical clearance of 10 mm (up, down, forward) satisfy the manufacturer's ventilation and arc-flash spacing. Operating temperature range is -25 to +60 °C; storage from -55 to +80 °C. The 60 °C ceiling covers most unventilated panel interiors, but derate switching frequency if ambient pushes above 40 °C — the thermal curve in the full datasheet governs that. Main contacts are 3-pole (3 normally open). An auxiliary switch block is included (yes per spec), so you have a feedback contact for PLC status without adding a separate side-mount. The contactor can be mounted in any orientation within ±180° rotation on a vertical surface, and tilted ±22.5° forward/backward — useful when fitting into tight or angled subpanels.