The Siemens 4EP3400-0JS00 is a 3-phase commutating choke for converter applications, rated 18 A continuous with a maximum of 20 A. Its 0.39 mH inductance shapes the current rise on the DC link or input side of a variable-speed drive, limiting di/dt and reducing harmonic stress on the upstream supply and the converter's semiconductors.
The 18 A rated current (I_LN) at 50 Hz with a 40 °C ambient is the continuous thermal limit for a 3-phase converter input or DC-link circuit. The 20 A maximum (I_thmax) allows short-term overload headroom. The 0.39 mH inductance and 0% relative inductive voltage drop (UK) mean this choke is designed for low-impedance insertion — it filters without dropping significant line voltage at rated current. The 32.6 W coil loss plus 4.6 W iron-core loss at 40 °C ambient gives a total dissipation of about 37 W; factor that into enclosure thermal calculations. Thermal class B per IEC 60085 means the insulation system withstands 130 °C hot-spot temperature, adequate for continuous duty in a ventilated cabinet.
Commutating chokes (also called line reactors or DC-link reactors) sit between the AC supply and a variable-frequency drive's rectifier, or in the DC link of a regenerative converter. They smooth current ripple, limit peak currents during commutation, and protect both the drive's input diodes and the upstream distribution from high-frequency harmonics. This 3-phase unit is sized for a converter in the 18 A class — typical for a 7.5 kW to 11 kW motor drive at 400 V three-phase.
Integration Notes
Mounting dimensions: 0.124 m width, 0.122 m height, 0.073 m depth. The free cable endings require a terminal block or lug connection inside the panel — no screw terminals on the choke body. Verify the cable cross-section matches your drive's input wiring; the choke is passive and polarity-independent for AC installation. Panel clearance around the IP00 core is recommended for airflow to dissipate the 37 W total loss.