What this reactor does on a VFD line
The SIDAC 4EU3951-0AR00-4B is a three-phase output reactor (output choke) rated for 120 A at 480 V AC, with a switching frequency up to 8 kHz and a maximum operating frequency of 1 400 Hz. It sits between the VFD and the motor to limit dv/dt and smooth reflected-wave voltage spikes — critical on long cable runs where standing waves can punch through motor winding insulation. The 0.1 mH inductance and 38 % impedance (UK) are sized for a nominal 108 A motor load, so it's a line-side fit for drives in the 75–90 kW range on 400–480 V systems.
Thermal class H and the open-frame reality
Thermal class H (180 °C winding rise) lets this reactor run hot without cooking the copper — a real need in a crusher or mill MCC where ambient can hit 40 °C and the panel is packed. Total iron plus coil losses run 453 W (148 W coil + 305 W iron), so plan for forced ventilation or a derated enclosure. IP00 means no dust or moisture protection; mount it inside a clean, filtered cabinet — not out on the plant floor where slurry and grit can settle on the windings. Flat-type terminals accept bus-bar or large-gauge ring lugs; torque per the nameplate values.