What it is and what it does
The Siemens SIRIUS 3RT1026-1HB40 is a S0-frame power contactor rated for motor switching in industrial control panels. Its 24 V DC coil draws 4.2 W during both closing and holding, so the coil supply can be a standard 24 V DC power supply without oversizing for inrush. The main contacts are screw-type terminals sized for 2x (0.75... 4 mm²) solid or 2x 10 mm² stranded, which covers most motor leads up to 11 kW. At 400 V, the AC-2 rating is 11 kW — that is the duty for slip-ring motors or moderate starting. For reversing or plugging duty (AC-4), the same contactor handles 15.5 A at 400 V. The AC-12 maximum operating current is 10 A, which covers resistive loads like heater banks. Type 2 coordination requires a 35 A gL/gG fuse upstream; Type 1 allows a 100 A fuse, giving flexibility in panel design.
Mounting and panel fit
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. The S0 frame is 45 mm wide, 85 mm tall, and 101 mm deep — a standard footprint that fits alongside other SIRIUS components on the same rail. Side-by-side mounting is allowed with 6 mm clearance at the side, so you can gang several contactors without wasting panel width. Front protection is IP20; the terminals themselves are IP00, meaning the panel enclosure provides the environmental seal. Operating temperature range is -25 to +60 °C, with pollution degree 3 (conductive or dry non-conductive pollution). Maximum operating altitude is 2000 m, so it is fine for most plant-floor installations without derating. Mechanical endurance is 10 million operations — a fast mover for high-cycle applications like conveyor lines.
Auxiliary contacts and wiring
The contactor carries no instantaneous auxiliary contact as standard (0 auxiliary contacts), so if you need feedback or interlocking, order a separate auxiliary contact block. The auxiliary contact ratings are: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, and 3 A at 400 V — all at the rated value. Wire sizes for the main circuit accept 2x (16... 12) AWG solid or 1x 8 AWG stranded.