The Siemens 4EU3921-0BV10-0A is a commutating choke (line reactor) for converter applications, designed to limit current rise rates and reduce harmonic distortion on the AC input side of a variable-frequency drive or DC drive. The 36 µH inductance (0.000036 H) and 3.88 % relative inductive voltage drop define the choke's impedance at rated conditions; this voltage drop is the design parameter that determines how much line-side filtering the choke provides. Higher impedance chokes suppress more harmonics but drop more voltage under load — this one sits in the moderate range, balancing filtering with voltage headroom for the drive's DC bus.
Thermal and mechanical constraints
Total power loss at rated load is 568 W — 326 W in the coil and 242 W in the iron core — all dissipated as heat inside the enclosure. Thermal class H (180 °C insulation system per IEC 60085) gives headroom for hot-spot temperatures, but the 40 °C ambient limit governs the installation: derate or increase airflow if the panel ambient exceeds that. Dimensions are 0.41 m wide × 0.385 m high × 0.229 m deep — a substantial component that needs a dedicated mounting footprint. The main circuit connects via flat-type terminals (bus-bar or heavy-gauge cable lugs), not screw-clamp or spring-cage; plan for bolted connections with appropriate torque and creepage distances for 400 V AC.