What it is and what it does
The Siemens 3RT1026-1AJ60 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads in industrial control panels. It is rated for 11 kW at 500 V in AC-3 duty, which covers the majority of standard induction motor starting applications at that voltage level. For the more demanding AC-4 duty — plugging and inching — it carries a continuous current rating of 15.5 A at 400 V, so it handles the higher thermal stress of frequent reversals without derating prematurely. The coil is wound for 92 V at 50 Hz and 110 V at 60 Hz, with an operating range of 0.8 to 1.1 times the rated voltage, meaning it pulls in reliably even if the control supply sags to about 74 V.
Mounting and panel integration
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. The S0 frame occupies 45 mm width, 85 mm height, and 91 mm depth — a compact footprint that fits standard 600 mm deep enclosures with room for wiring gutters. Side-by-side mounting is permitted with zero lateral spacing, so you can pack contactors tightly on the rail; the 6 mm clearance to adjacent components is only needed on the front face for arc flash containment. The main circuit uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded, with a maximum of 2x 4 mm². For the main contacts, the range extends to 2x 10 mm² or 1x AWG 8. Pollution degree 3 rating means it's suitable for the conductive-dust environment typical of a control panel without conformal coating.
Environmental and mechanical limits
Operates from -25 to +60 °C, which covers most indoor panel environments; above 40 °C, derate the continuous current per the thermal curve in the datasheet. Maximum operating altitude is 2 000 m without derating — above that, the reduced air density lowers the arc-quenching capability, so you'd need to apply the altitude correction factor. The front face carries IP20 finger protection; the terminal area is IP00, so the panel door must provide the enclosure-level IP rating. Mechanical endurance is 10 million operations typical, which for a contactor cycling once per minute gives over 19 years of service life before the spring set fatigues.
Auxiliary contact ratings
The single normally-open auxiliary contact is rated for 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. These are the make-and-break capacities for the control circuit; if you're switching a PLC input or a relay coil, stay within these limits to avoid contact welding. The ratings drop with voltage because the arc energy increases, so at 220 V DC the contact is limited to 0.3 A.