The Siemens 3RT1026-1AC24-0AA1 is a SIRIUS S0-size power contactor rated for motor switching and general load control. The 24 VAC/DC coil pulls in reliably across the full rated voltage tolerance, and the contactor is rated for 11 kW at 690 V in AC-3 duty — enough for a 15 kW motor at 400 V, or 11 kW at 690 V. The S0 frame keeps the footprint tight at 45 mm wide, 85 mm tall, and 140 mm deep, so it fits standard 35 mm DIN rail (screw or snap-on per DIN EN 50022) without crowding adjacent devices.
Where it survives
This contactor is built for the panel, not the office. It's rated for pollution degree 3 — the environment inside a typical industrial enclosure where conductive dust and condensation are normal. IP20 on the front face keeps fingers and tools out; the terminals themselves are IP00, so the contactor needs to be inside an enclosure that provides the final IP rating.
Both the main current circuit and the auxiliary contacts use screw-type terminals. The main circuit accepts 2x (1 to 2.5 mm²) solid or stranded, 2x (2.5 to 6 mm²), or a single 10 mm² conductor. The auxiliary contacts take 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), max 2x 4 mm². For AWG, the main terminals handle 2x (16 to 12), 2x (14 to 10), or 1x 8 AWG. The two instantaneous auxiliary contacts (NO/NC) are rated for 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V — enough to signal a PLC input or drive a pilot light directly.
For Type 2 coordination (contactor remains usable after a fault), the fuse must be 35 A gL/gG. These are the values to hand to the panel builder when sizing the branch circuit protection. The contactor itself has a mechanical life of 10 million operations typical, so it will outlast most machines it controls.