What the ratings mean for fit
The Siemens 3RT1034-1AK64 is a SIRIUS power contactor in frame size S2, rated for motor switching at 18.5 kW on a 500 V AC-3 supply and 15 kW at 400 V AC-2. AC-3 is the standard duty for squirrel-cage motors during starting and running; AC-2 covers wound-rotor motors where switching occurs at reduced current. The contactor carries a maximum 1 000 operations per hour in AC-3, so it handles frequent start-stop cycles on conveyors or pumps without derating. The main current circuit uses screw-type terminals, accepting stranded wire up to 2x 25 mm² and solid conductors up to 2x 4 mm². That covers motor leads up to about 6 AWG stranded, common for 15–20 kW drives. The auxiliary contacts are rated for switching at 24 VDC (10 A) down to 220 VDC (0.3 A), which covers PLC outputs and relay coils in the control cabinet.
Mounting and panel integration
Mounts by screw or snap-on onto a 35 mm standard mounting rail per DIN EN 50022. Side-by-side mounting is permitted, so multiple contactors can pack tightly in a row without derating. The front face carries IP20 protection (finger-safe terminals), while the connection points at the terminals are rated IP00 — keep live parts behind a panel door or cover. Dimensions are 112 mm high, 55 mm wide, and 164 mm deep. That depth includes the terminal overhang; allow clearance for screwdriver access and cable bending radius when laying out the enclosure.
Environmental and installation notes
Rated for operation from -25 °C to +60 °C ambient, with storage from -55 °C to +80 °C. Pollution degree 3 means it tolerates conductive dust and humidity typical of industrial control rooms and light manufacturing floors. Coil operating range is 0.8 to 1.1 times rated voltage at both 50 Hz and 60 Hz, with pick-up time of 7–20 ms and arcing time of 10–15 ms.