What this choke does in a drive line
The Siemens 4EU4321-1DA00-0A is a three-phase commutating choke (Kommut.-Drossel f. Stromrichter) designed for the DC link or AC input of a converter drive. Its job is to limit the rate of rise of current (di/dt) during thyristor or IGBT commutation, reducing switching losses and suppressing harmonics that would otherwise reflect back onto the supply. Rated at 720 A continuous with a peak capability of 1 000 A, it handles the repetitive current pulses a six-pulse rectifier draws without saturating the core. That 4 % figure is the key spec for sizing: too low and commutation notches get worse; too high and the DC bus sags under load.
Thermal and mechanical constraints for panel integration
IP00 means no enclosure — the choke is a bare magnetic assembly intended for mounting inside a ventilated cabinet. The combined power loss is 760 W (460 W in the coil, 300 W in the iron core), so forced-air cooling or a generously sized enclosure with natural convection is required. Class H insulation (180 °C thermal class per IEC 60085) gives a 40 °C ambient rating with headroom for hot-spot rise; derate the continuous current if the cabinet ambient exceeds that. The footprint is 0.46 m wide × 0.435 m tall × 0.265 m deep — a substantial panel-mounted component. Terminals are flat-type connectors for bolted bus-bar or cable-lug connections; plan for access on both sides. No DIN-rail clip — this is a through-bolt or bracket mount.