The Siemens 4EU4521-0BP10 is a commutating choke (line reactor) for a converter — the thing that sits between the drive and the line to smooth current spikes and limit fault current rise rates. It's a 3-phase AC choke rated for 1170 A continuous at 380 V, 50 Hz, with an inductance of 0.035 mH. The 1170 A rating is the thermal continuous current (Ith) — that's the max RMS current it can carry indefinitely without exceeding the 40 °C ambient temperature rise limit. In DC applications it's rated 1433.8 A, so it handles the higher RMS of rectified current without saturating. IP00 means it's an open-frame component — no enclosure, no drip shield. It lives inside a cabinet, not on the wall. Mounting dimensions are 0.46 m wide by 0.435 m tall by 0.293 m deep, so plan the panel real estate accordingly.
That's typical for commutating duty: high enough to limit di/dt for the converter's thyristors, low enough to keep voltage drop manageable under load. Thermal class H insulation handles sustained hot spots. Power loss is 746 W in the coil and 263 W in the iron core. Connections are flat-type terminals. Use a busbar or flat braid for power cables.
At 0.46 m wide, 0.435 m tall, and 0.293 m deep, this choke takes up a significant footprint — roughly the size of a small suitcase. It's not a DIN-rail component; it bolts directly to the backplate or a mounting frame. Heat dissipation is 746 W coil plus 263 W core. At 40 °C ambient, account for thermal rise in the enclosure.