Mains choke for variable-frequency drive lines
The Siemens 4EU4351-3UB00-0A is a three-phase mains choke (Netzdrossel für FU) rated for 1120 A maximum continuous current and 1008 A nominal, designed to sit between the supply and a frequency converter's input rectifier. Operating at 400 or 480 V AC, 50/60 Hz, it presents a 4 % relative inductive voltage drop at rated current — the standard sizing for drive input chokes that limit harmonic distortion and reduce peak charging currents. The 25 µH inductance (0.025 mH) is matched to the 1008 A rating; at this power level the choke also absorbs line-side transients and smooths commutation notches that otherwise stress the DC-link capacitors.
The 1008 A nominal is the rated continuous current (I LN) at which the 4 % voltage drop is measured; below that current the drop scales linearly. Dimensions are 0.265 m deep, 0.46 m wide, 0.435 m tall; plan for mounting on a flat panel or chassis, not a DIN rail.