Siemens SIRIUS 3RT1034-3AP08-1MA2 Power Contactor — Sizing and Fit
The Siemens 3RT1034-3AP08-1MA2 is a SIRIUS power contactor in Size S2, designed for switching motor loads in industrial control panels. Its AC-2 rating of 15 kW at 400 V covers wound-rotor motor applications, while the AC-4 rating of 29 A at 400 V handles reversing and inching duty — the high-stress cycles that generate arcing across the main contacts. The contactor carries a mechanical life of 10 million operations, so it holds up in high-cycle packaging or material-handling lines where contactors get cycled hundreds of times an hour.
Mounting and Integration
Mounts via screw and snap-on onto a 35 mm standard mounting rail per DIN EN 50022. The 55 mm width means it occupies a single modular unit on the DIN rail, so panel layout stays predictable — no overhang into adjacent device slots. Side-by-side mounting is supported, so you can gang multiple contactors without derating for heat buildup, as long as ambient stays within -25 to +60 °C during operation.
Termination and Wiring
Screw-type terminals on the main current circuit accept solid conductors from 0.25 to 2.5 mm² (two per clamp) and stranded conductors from 0.75 to 25 mm² (two per clamp). The 16 mm² minimum at 40 °C tells you the lug sizing for full-rated current — don't undersize the feed wire if you're pulling the full AC-4 load. The IP20 front means the contactor is finger-safe once installed inside an enclosure; the terminal area itself is IP00, so keep it behind a panel door or cover.