What it is and what it does
The Siemens 3RT1034-3XB44-0LA2 is a SIRIUS power contactor in the Size S2 frame, designed for switching motor loads in industrial control panels. It carries screw-type terminals on the main current circuit and provides 2 instantaneous auxiliary contacts. Rated for motor duty at 18.5 kW at 500 V and 10 kW at 690 V, this contactor handles the typical three-phase induction motor loads found on conveyors, pumps, and compressors in a 400 V to 690 V line. The operating temperature range of -40 to +70 °C covers most indoor panel environments, including unheated plant floors.
Mounting and panel integration
Mounts via screw fixing or snap-on onto a 35 mm standard mounting rail per DIN EN 50022. The 55 mm width and 142 mm height fit a standard DIN-rail footprint, with 10 mm clearance required upwards, downwards, forwards, and at the sides for airflow and wiring access. Side-by-side mounting is permitted, so multiple contactors can be ganged without additional spacing — useful when building a compact motor starter bank.
Wiring and termination
Main circuit terminals accept solid conductors 2x (0.25 to 2.5 mm²) and stranded conductors 2x (0.75 to 25 mm²), with a maximum cross-section of 16 mm² for AC-1 rated connections. The screw-type termination is field-serviceable with standard tools. Auxiliary contact ratings: 10 A at 24 V DC, 6 A at 230 V AC, and 2 A at 60 V DC, covering typical PLC and relay interface loads.
Lifecycle and sourcing reality
For a critical-spare holding on an existing SIRIUS-based panel, this is the direct drop-in replacement for the same Size S2 footprint. Quoted to order against an RFQ — confirm quantity and lead time with your sourcing desk.