The Siemens 4EU3931-4AA00-0A is a 3-phase AC filter choke — a Filterdrossel — rated for 297 A maximum and 267 A continuous, with 0.23 mH inductance. It sits between a drive and the line to smooth current ripple and limit harmonic distortion, sized for a 50 Hz line. The 375 W coil loss and 220 W iron-core loss tell you this is a substantial component; plan for the heat in the enclosure.
IP00 means no ingress protection — this choke is for inside a cabinet, not on the plant floor. It measures 0.41 m wide by 0.385 m tall by 0.229 m deep, so it needs a dedicated mounting plate or chassis bracket, not a DIN rail. The main circuit connects via flat connectors, so expect busbar or cable-lug terminations, not screw terminals.
Thermal class and operating conditions
Rated for a 40 °C ambient and built to thermal class H per IEC 60085, which means the insulation system can handle a 180 °C hot-spot temperature. That headroom is typical for chokes in high-harmonic or overload-prone drive applications. The 21.3 V operating voltage is the voltage drop across the choke at rated current, not the line voltage — this is a low-impedance series element.