The Siemens 4EU4321-0CB10-0A is a three-phase commutating choke for converter applications — the component that limits the rate of rise of current during thyristor or IGBT switching, protecting the converter bridge from di/dt stress and reducing line notching.
The 1620 A rated current (I LN) is the continuous thermal current the choke can carry at 40 °C ambient without exceeding its Class H (180 °C) insulation system. The 1800 A maximum (I th max) is a short-time thermal limit — use it for overload sizing, not steady-state. The 4 % relative inductive voltage drop (UK) at rated current and frequency tells you the voltage the choke consumes at full load; factor it into your drive's DC-link voltage budget. Inductance is 0.013 mH (13 µH) — a low value typical for large commutating chokes where the goal is just enough inductance to limit di/dt without dropping excessive voltage. Total power loss is 1000 W (670 W coil + 330 W iron core), all dissipated as heat.
Physical fit and termination
The choke measures 0.460 m wide × 0.435 m high × 0.265 m deep. Main circuit connections are flat-type terminals — expect busbar or heavy cable lugs, not wire ferrules. Verify the terminal hole pattern against your existing busbar layout before ordering.