SIRIUS 3RT2026-1BD40 — Size S0 Power Contactor with 42 V Coil
The Siemens SIRIUS 3RT2026-1BD40 is a Size S0 power contactor with a 42 V coil. It switches motor loads and resistive circuits in industrial control panels. The coil holds at 42 V nominal; the operating range spans 0.8 to 1.1 times the rated value. Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, and the mounting position allows +/-180° rotation on a vertical surface plus +/-22.5° tilt forward and backward — enough flexibility to fit tight enclosures without derating.
Switching Capacity and Duty Ratings
For motor starting (AC-3 duty), the contactor is rated for 3 hp at 230 V — that's the headline number for a 3-phase motor on a 230 V line. At 400 V, the AC-3 rating is 3 A, so it handles smaller motors at higher line voltages. DC switching is specified per voltage step: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V. These are resistive-load ratings (AC-1 equivalent); inductive DC loads need derating or arc-suppression across the contacts. Mechanical switching frequency limits vary by duty: 1 000 cycles/hour for AC-1 (resistive), 750 cycles/hour for AC-2 and AC-3 (motor start/run), and 250 cycles/hour for AC-4 (plugging/inching). The arcing time sits at 10 ms, typical for a Size S0 contactor.
Lifecycle and Sourcing
The closest functional peer is the 3RT2026-1FB44-3MA0, which carries a different coil voltage but shares the same Size S0 frame and screw-terminal layout.
Integration and Clearance
Dimensions: 85 mm height, 45 mm width, 107 mm depth. Minimum clearance around the contactor: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the sides. These are for ventilation and arc-quenching — stacking contactors closer than that requires thermal derating. Wire range: solid or stranded 1 to 10 mm² for the main power circuit, and 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) for auxiliary/control wiring. Screw terminals are standard; torque values follow the manufacturer's tightening spec on the terminal face.
Environmental and Mechanical Life
Operating temperature range: -25 to +60 °C. Storage range: -55 to +80 °C. The storage limit governs handling during shipping and off-season storage, not running conditions. Mechanical service life is 10 000 000 operations typical — that's the contactor mechanism itself, not the electrical endurance under load. Electrical life depends on switching current and duty cycle; for AC-3 at rated current, expect roughly 1 to 2 million operations. An auxiliary switch is built into the contactor (yes/no flag indicates yes), so no separate add-on block is needed for basic status feedback to the PLC or indicator lamp.