What this contactor is and what it does
The Siemens SIRIUS 3RT1034-1AQ66 is a power contactor in the S2 frame size, designed for switching motor loads in industrial control panels. It carries an AC-2 rating of 15 kW at 400 V for slip-ring motors and an AC-3 rating of 18.5 kW at 500 V and 10 kW at 690 V for standard squirrel-cage induction motors. The 50/60 Hz coil operates across a 0.8 to 1.1 voltage range, so it holds in during dips but drops out cleanly below the undervoltage threshold. Mounting is screw-and-snap-on onto 35 mm DIN rail per EN 50022, with side-by-side mounting permitted for dense panel layouts. The front face carries IP20 finger protection; the terminal area is IP00, which is typical for panel-internal contactors where the enclosure provides the outer seal.
Key ratings and what they mean for fit
The 18.5 kW at 500 V (AC-3) and 10 kW at 690 V (AC-3) are the numbers that decide motor fit — match these to the nameplate kW of your induction motor. For slip-ring or wound-rotor motors, use the AC-2 rating of 15 kW at 400 V. The contactor also has specified AC-1 resistive ratings for heater or lighting loads, with a maximum operating frequency of 1 200 cycles per hour in that duty. The auxiliary contact block is rated for switching at 24 V (10 A), 60 V (2 A), 110 V (1 A), 220 V (0.3 A), 230 V (6 A), and 400 V (3 A). These are the values for control-circuit isolation — verify your PLC output or relay matches the voltage and current you're switching. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. Pollution degree 3 means it's suited for industrial environments with conductive dust or occasional condensation, which is standard for panel-mounted gear.
Lifecycle and sourcing reality
The screw-type terminals on the main circuit accept solid conductors from 2x (0.5 to 4 mm²) and stranded from 2x (0.75 to 25 mm²). The control circuit terminals accept 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded. These are the wire ranges for panel wiring — no special lug kit needed for standard builds.
Panel integration notes
Dimensions are 112 mm high, 75 mm wide, 115 mm deep — the S2 frame occupies the same footprint as other SIRIUS S2 contactors, so a panel laid out for a 3RT1036 will accept this unit without drilling changes. Side-by-side mounting is allowed, so no spacing gaps are required between units on the rail.