What this choke does on the line side
The Siemens 4EU4551-6UA00 is a three-phase mains choke (Netzdrossel f. FU) rated for 1250 A continuous at 500 V AC, with a relative voltage drop of 4 % at rated current and frequency. That 4 % inductive drop is the key design parameter — it limits the rate of rise of fault current and smooths the DC-bus charging profile on the drive input, which is why you see this choke between the supply and the frequency converter rather than on the motor side. Inductance is 0.029 mH (29 µH), wound for a 50/60 Hz line. The 711 W copper loss plus 369 W iron loss sum to roughly 1.08 kW of heat that has to leave the enclosure — that is not a trivial thermal load. With IP00 protection and thermal class H (180 °C insulation system per IEC 60085), this choke expects to be mounted in a ventilated cabinet where that heat can rise out; it is not a sealed-box part.
Footprint is 0.46 m wide × 0.435 m tall × 0.293 m deep — about the size of a small suitcase. Plan for M10 or M12 bolt-down terminations and a cutout that clears the 460 mm width plus bending radius for incoming cables.