The Siemens 4EU4321-0BD00-0A is a commutating choke (line reactor) for converter applications — 3-phase, 690 V AC rated voltage, 1640 A maximum current, 1476 A rated current, and 0.015 mH inductance. Built to EN 61558-2-20, it limits current rise and harmonics on the AC side of a drive or converter, protecting the semiconductor bridge from commutation notches and reducing line-side distortion.
The 1640 A maximum current (Ithmax) at 50 Hz sets the thermal limit for continuous operation — sized for a 1476 A nominal (ILN) converter input. The 0.015 mH inductance is low — typical for a high-current, high-frequency commutating choke rather than a bulk line reactor; it targets the commutation notch, not total harmonic filtering. Thermal class H (180 °C) insulation per IEC 60085 allows the choke to run hot in a sealed cabinet. Total power loss is 995 W (670 W coil + 325 W iron core) at rated conditions — that heat must be vented or the enclosure derated accordingly. IP00 means no ingress protection; the choke requires a cabinet with at least IP2X or better to keep tools and debris off the windings.
Commutating chokes sit on the AC input of a 3-phase converter or drive, between the supply and the rectifier. They limit the rate of current rise (di/dt) during commutation, reducing voltage notches that can trip upstream protection or radiate EMI. They also smooth the DC-link current ripple to some degree. This class of part is standard on any medium-to-high-power drive installation where the line impedance is low or where the drive manufacturer specifies an external choke for the frame size.
Footprint is 0.46 m wide × 0.435 m high × 0.265 m deep — a substantial enclosure; verify panel door clearance and busbar access before laying out. Main circuit connection uses flat-type terminals (busbar or cable lug), not spring-cage or screw-clamp. No DIN-rail mount — the choke bolts directly to a mounting plate or chassis.