What this contactor is and what it does
The Siemens 3RT1026-3XF44-0LA2 is a SIRIUS-brand power contactor in the size S0 frame, built for switching motor loads and other inductive circuits in industrial control panels. It lands on a 35 mm DIN rail (DIN EN 50022) via screw and snap-on mounting, with a 45 mm width that fits standard panel layouts. The 110 V DC coil includes a built-in varistor surge suppressor, so you don't need to add an external snubber for DC switching transients.
What the ratings mean for your motor or load
The AC motor ratings give you the real-world switching capacity: at 460/480 V the contactor handles 15 hp, at 575/600 V it handles 20 hp — those are the numbers that matter when you're sizing for a pump or conveyor. For DC switching, the contactor is rated 10 A at 24 V, 1 A at 110 V, and 0.3 A at 220 V; the DC-13 duty curve governs, so if you're switching solenoids or DC brake coils, stay inside those curves. The AC-4 rating at 400 V is 15.5 A, which covers inching and plugging duty on smaller motors.
Coil pickup and drop-out — what to expect
The coil picks up at 70 % of rated voltage (0.7 x 110 V = 77 V DC) and drops out at 125 % (1.25 x 110 V = 137.5 V DC). That's a standard DC coil curve; the varistor across the coil absorbs the back-EMF when you de-energize it, which keeps the switching noise off your 24 V DC control bus. Ambient temperature range during operation is -40 to +70 °C, so it'll sit in a hot panel next to a drive or in a cold warehouse without trouble.
Wiring and clearances
Main circuit terminals are screw-type, accepting 2 x (0.25 to 2.5 mm²) solid or stranded, or up to 2 x 10 mm². The auxiliary contact block has 2 normally-open instantaneous contacts. For side-by-side mounting on the DIN rail, you need 10 mm clearance upwards, forwards, and downwards, and 10 mm at the side — no extra gap required between contactors, so you can pack them tight in a row. The depth is 150 mm, height 119 mm.