The SIDAC 4EU4521-0CG08-0B is a 3-phase output reactor rated 107 A continuous with a 4 kHz switching frequency. It sits between the drive output and the motor cable — the job is to limit the rate of voltage rise (dV/dt) from the PWM pulses, protect the motor winding insulation, and reduce bearing currents. At 0.8 mH and 400 V class, it is sized for a motor load pulling around 107 A line current, typical of a 55–75 kW induction motor on a 400 V three-phase supply.
The 4 kHz switching frequency matches modern IGBT drives; older 2 kHz drives also work, but the core losses drop. The 780 W coil loss plus 490 W iron loss total about 1.27 kW of heat that must be ventilated — IP00 means no enclosure, so it is intended for a cabinet with forced air or natural convection clearance. A 46.3 % impedance voltage (UK%) means the voltage drop at rated current is significant; account for it in the motor terminal voltage budget.