The Siemens 4EP3605-0AS00 is a three-phase commutating choke (line reactor) designed for converter front-ends. It limits current rise during commutation, reducing harmonic distortion and protecting the DC link from switching transients. Rated for 50 A continuous with a 56 A maximum thermal current (Ithmax) at 50 Hz, 230 V AC three-phase. The 0.15 mH inductance (0.147 mH per the spec line) gives a 2 % relative inductive voltage drop — meaning it's sized for moderate impedance, not heavy filtering.
The 56 A maximum (Ithmax) is the thermal limit under worst-case conditions — the choke can handle short-term overloads up to that level without exceeding Class B insulation temperature rise (ambient 40 °C). The 50 A rated current (I LN) is the continuous design point for normal operation. At DC, the rated value is 68.6 A — relevant if the choke is used on the DC side of a converter, though the primary application is AC line-side commutation. Screw-type terminals accept standard lug or ring-terminal connections.
Mounts in the AC line between the supply and the converter input, typically in a control cabinet. The open-frame design (IP00) requires clean, dry, non-conductive surroundings — not for washdown or outdoor use without an enclosure. Rated ambient temperature is 40 °C with Class B insulation, so derating is needed if cabinet internal temperature exceeds that. The 50 Hz operating frequency is standard for mains applications.