Integrator's note on the 3RT1034-3KF44-0LA0
The Siemens SIRIUS 3RT1034-3KF44-0LA0 is a S2 frame power contactor rated for motor switching at 18.5 kW on 500 V AC-3 duty, or 10 kW at 690 V AC-3. That AC-3 rating is the one that governs real motor loads — the 29 A AC-4 figure at 400 V covers reversing or inching duty where contact wear is higher. Coil is 110 V DC, which means you need a separate DC supply or a rectifier module in the panel; verify your control transformer and rectifier sizing before wiring. Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022. Screw-type terminals on the main circuit accept up to 2x 25 mm² stranded or 2x 16 mm² solid. Pollution degree 3 rating means it's suited for industrial enclosures where conductive dust or condensation is present — standard for most control panels, but not for clean-room or sealed electronics cabinets without derating. Operating temperature range of -40 to +70 °C covers most plant-floor environments; storage range extends to -55 to +80 °C. Mechanical endurance is rated at 10 million operations typical, so it's built for high-cycle applications like conveyor lines or packaging machines.
Sourcing and lifecycle posture
RoHS compliance date is noted as May 1, 2012, so the design predates the more recent substance restrictions but meets the original RoHS directive. If your compliance team needs a Declaration of Conformity or REACH documentation, that's standard Siemens paperwork available through the supply chain.
Termination and wiring details
Main circuit terminals accept 2x (0.75...25 mm²) stranded or 2x (0.25...2.5 mm²) solid wire. At 40 °C, the minimum permissible cross-section is 16 mm² for the main conductors — that's the thermal limit for full rated current, not a mechanical minimum. Side-by-side mounting is allowed with no derating penalty, which saves panel width when stacking multiple contactors.