The Siemens 4EP3701-3DS00 is a commutating choke (line reactor) designed for use with converters — the German product designation "Kommut.-Drossel f. Stromrichter" says it plainly. It's a 3-phase AC choke rated at 18 A continuous (20 A maximum) at 500 V operating voltage, with an inductance of 1.8 mH.
Rated at 18 A with a 20 A maximum — the 18 A figure is the continuous thermal rating at 40 °C ambient (thermal class B insulation). Coil loss is 50 W and iron core loss is 12.4 W.
Where It Goes — Deployment Context
This choke sits between the AC line and a variable-frequency drive or DC drive input. Its job is to limit the rate of current rise during commutation — reducing harmonic distortion, protecting the converter's input diodes/thyristors, and smoothing the DC link. The 50 Hz operating frequency is standard for European-line applications. The 0.105 m depth, 0.178 m width, and 0.153 m height are the physical envelope for panel layout — it's a compact block, not a chassis-mount reactor.