The SIDAC 4EU4551-0AG10-0B is a three-phase output reactor — a choke that sits between a variable-frequency drive and the motor to smooth the PWM waveform, limit voltage spikes, and reduce bearing currents. It's rated for a continuous 745 A at 50 Hz, with an inductance of 0.079 mH and an impedance voltage (uk) of 8%. The 745 A figure is the thermal maximum (Ithmax) at 40°C ambient, so that's the number to use for continuous-duty sizing. For a junior on the panel: if your drive's output current stays under 745 A at 40°C, this reactor can handle it without derating.
The 745 A continuous rating at 40°C ambient tells you this is a large-frame reactor — sized for a drive feeding a motor in the 400–500 kW range on 400 V three-phase. The 0.079 mH inductance is relatively low, which means it's designed for high-current, low-impedance motor circuits where you mainly want to limit dv/dt and reflected-wave effects on longer cable runs, not add significant line impedance. Total power loss is 1083 W (671 W coil + 412 W iron core), so factor that into your enclosure ventilation — at that dissipation, forced airflow or a larger cabinet is needed. Class H insulation (180°C thermal class per IEC 60085) gives good margin for high-ambient or overload conditions.
IP00 protection class. Flat-type terminals for main circuit connections. Dimensions: 0.46 m wide × 0.43 m tall × 0.29 m deep.