The Siemens 4EM5008-0AK00 is a commutating choke — a line reactor — designed for a single-phase converter input. It sits between the AC supply and the converter's rectifier, smoothing current peaks and limiting di/dt during commutation.
Rated for 27 A continuous with a 30 A maximum at 400 V AC, 60 Hz. That 27 A figure is the thermal current under the rated conditions — 40 °C ambient, thermal class B insulation per IEC 60085. The 30 A ceiling is the short-term overload. On a 400 V line, this choke handles a 27 A RMS fundamental; the 3% voltage drop means about 12 V across the choke at full load, which the converter's DC bus regulation absorbs without issue. The total power loss splits between the coil (14.2 W) and the iron core (26.2 W) — roughly 40 W dissipated in the panel, so keep some air movement around it.
IP00 — no enclosure, so it needs to live inside a panel or cabinet. The 0.115 m depth, 0.097 m width, and 0.111 m height make it a compact block, about the size of a contactor. No DIN-rail clip; it bolts directly to the panel backplate. Plan for the 40 W heat dissipation in your thermal budget.