The Siemens 4EU4321-4DA00-0A is a three-phase commutating choke (line reactor) designed for converter front-end circuits. It limits di/dt and reduces harmonic distortion on the AC line feeding a variable-frequency drive or DC drive. Rated for 630 A maximum continuous current at 750 V AC, 50 Hz, with a rated inductance of 68 µH and a relative inductive voltage drop of 4% at rated current.
The 630 A maximum current rating and 567 A rated current tell you this choke is sized for a 400–500 kW drive on a 400 V class system — the peak current capability of 788 A handles short-duration overloads during motor acceleration. Its 68 µH inductance with a 4% voltage drop means it provides moderate line impedance to smooth current ripple without excessive volt-drop under load. Power loss splits into 480 W in the coil and 300 W in the iron core, totaling 780 W at rated load. This heat must be managed: the IP00 enclosure means no dust or moisture protection — mount it in a ventilated cabinet or dedicated enclosure. Thermal class H insulation allows a 180 °C hot-spot rating, so it survives the internal temperature rise, but the 40 °C ambient rating is the design point for the surrounding air. Dimensions are 0.46 m wide × 0.435 m high × 0.265 m deep. Flat-type terminals accept busbar or cable lug connections — plan for a bolted interface, not a spring-clamp or screw terminal. The 0.265 m depth is the critical dimension for enclosure depth selection.
Marked at a mature lifecycle stage. This is not a new-release product, but it remains in the active Siemens catalog for drive system spares and new installations. It carries UL and CSA recognition per EN 61558-2-20, which covers safety of transformers, reactors, and power supply units — a key authority signal for North American panel builders requiring third-party certification.