What this contactor is and where it lands
The Siemens 3RT1026-1AQ24 is a SIRIUS power contactor in the S0 frame size, built for switching three-phase motor loads up to 11 kW at 400 V AC-3. The 24 VDC coil draws its holding current from the control transformer, and the screw-type main terminals accept up to 10 mm² stranded or 8 AWG. Snap it onto a 35 mm DIN rail per EN 50022 — side-by-side mounting is allowed with 6 mm spacing between units. This is a current-production part. The S0 frame means it fits the standard 45 mm wide slot in a motor control center bucket, and the pollution degree 3 rating confirms it's rated for the conductive-dust environment inside a typical industrial panel. Front face is IP20 — safe for finger-probe access; the terminal area is IP00, so live parts are exposed once the arc shield is removed.
Wiring and installation notes
Main circuit screw terminals accept 2x (0.5…1.5 mm²) solid, 2x (0.75…2.5 mm²) solid, or up to 2x 4 mm² solid. For main current path: 2x (1…2.5 mm²) or 2x (2.5…6 mm²) stranded, max 2x 10 mm². Operating temperature -25 to +60 °C; maximum altitude 2 000 m. Coil operating range 0.8…1.1 x rated voltage at 50 Hz, 0.85…1.1 at 60 Hz.
Ratings that decide the fit
AC-3 motor switching at 400 V: 11 kW. That's the headline number for a standard induction motor load — pumps, fans, compressors up to that power. AC-4 at 400 V is rated 15.5 A, for reversing or inching duty where the contacts make and break stalled-rotor current. AC-2 at 400 V also 11 kW, for slip-ring motor starting. The auxiliary contact block has 2 instantaneous contacts. Mechanical life is 10 million operations typical. Short-circuit protection: for Type 2 coordination (no weld) use a 35 A gL/gG fuse; for Type 1 (weld allowed, replace contactor) use 100 A gL/gG. The contactor also carries resistive load ratings at various voltages — 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 1 A at 110 V, 0.3 A at 220 V. These matter for heater or lighting contactor applications where the load isn't a motor.