The Siemens 4EP3400-0CK00 is a 3-phase mains choke (Netzdrossel f. FU) designed for use with frequency converters. It carries a rated current of 2.4 A at 400 V AC, with an inductance of 18 mH and a relative inductive voltage drop of 6% at rated conditions. That 6% drop is typical for line reactors sized to limit harmonic distortion and reduce peak currents on the drive input — it's not a voltage-regulation device, but a smoothing and protection element for the converter's rectifier stage.
Rated for a 50 Hz line frequency (0–50 Hz operating range), thermal class B per IEC 60085, and an ambient temperature of 40 °C. Connections are via screw-type terminals or tab terminals, which suits standard panel wiring practices. Dimensions: 0.124 m wide, 0.122 m high, 0.073 m deep — a compact footprint for a 2.4 A three-phase reactor.