Siemens 3RT2038-3XJ40-0LA2 SIRIUS Contactor — 72 VDC Coil, Spring-Terminal, Size S2
The Siemens 3RT2038-3XJ40-0LA2 is a SIRIUS-brand contactor in the S2 frame size, designed with an extended operating-range DC coil rated at 72 V and spring-type terminals for tool-free wiring. It switches motor loads up to 65 A at 480 V and delivers 15 hp at 230 V, making it a fit for medium-duty conveyor, pump, and fan applications inside a control panel.
Key Ratings and What They Mean for Fit
The 65 A rating at 480 V and 62 A at 600 V define the AC-3 motor-switching capacity — this contactor handles three-phase induction motors up to roughly 30 kW at 480 V without derating. The 15 hp at 230 V single-phase rating covers smaller loads on split-phase panels. DC switching capability is voltage-dependent: 10 A at 24 VDC, 2 A at 48 VDC, 1 A at 110 VDC, and 0.3 A at 220 VDC — the coil and arc chute are sized for DC interruption, so it works in battery-backed or rectified DC control circuits, but the current drops sharply above 48 V. The spring-type terminals accept 2x (0.5 to 2.5 mm²) solid or stranded wire — no screw torque to verify, which speeds panel wiring and eliminates a common re-torque failure point during commissioning. The coil draws DC only, so confirm your control transformer or power supply outputs clean 72 VDC; an AC coil variant would use a different order code. Mounting is via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward on a vertical surface — useful when the panel layout forces an unconventional orientation. Clearance distances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. These are the minimum air gaps to adjacent metalwork or another device; pack them tighter and arc flash or heat dissipation becomes a problem.
Integration and Panel Fit
The contactor occupies 55 mm width, 114 mm height, and 130 mm depth — the depth is the critical dimension when the contactor sits behind a panel door or near a busbar shroud. The S2 frame shares the same footprint as other SIRIUS S2 devices (overload relays, reversing contactors), so a multi-device motor starter group aligns on the same DIN-rail pitch. Operating temperature range is -40 to +70 °C; storage range is -55 to +80 °C. The -40 °C floor matters for unheated warehouses or outdoor enclosure installations in cold climates — the coil must pull in reliably at that low end, and the contactor's mechanical life of 10 million operations typical assumes no lubrication degradation from thermal cycling.