The Siemens 4EP3601-4DS00 is a three-phase commutating choke (line reactor) designed for use with converters (variable frequency drives). It sits between the AC line and the drive input, limiting current rise rates and reducing harmonic distortion. Rated for 400 V AC at 50 Hz, it handles a maximum AC current of 18 A and carries a rated inductance of 1.2 mH (1.24 mH per the description).
Three key numbers decide whether this choke fits your drive line: the AC current rating (18 A maximum), the inductance (1.2 mH), and the voltage drop (4%). The 18 A AC maximum is the thermal limit for continuous operation at 40 °C ambient — if your drive draws more than 18 A continuous, step up to a higher-rated reactor. The 1.2 mH inductance determines the impedance at 50 Hz (about 0.38 Ω); this is what limits the inrush and shapes the line current. The 4% voltage drop is typical for a line reactor sized to the drive's nominal current — it provides enough impedance to reduce harmonics without dropping too much voltage under load. The choke also carries a peak current rating of 23 A and a DC rated current of 22 A, which are surge and short-duration limits, not continuous ratings. Power loss is split between the coil (39 W) and the iron core (7 W), for a total of 46 W at rated load. The thermal class is B (130 °C rise) per IEC 60085, which is standard for dry-type reactors in industrial panels.
This is a panel-mount component. Dimensions are 0.148 m wide, 0.126 m tall, and 0.078 m deep. That's about 5.8 x 5.0 x 3.1 inches, so it fits on a standard DIN-rail mounting plate or directly on a back panel. Leave clearance around it for airflow; the 46 W heat dissipation needs ventilation, not tight enclosure against other heat sources. The IP00 protection class means no gasket or sealed housing — keep it dry and clean inside the cabinet.