The SIDAC 4EU3951-0AP80-0A is a 3-phase output reactor rated for 400V AC systems with a maximum continuous current of 100A. Inductance is 0.0003 H, designed for a switching frequency of 8 kHz.
Rated 100A maximum continuous current and 0.3 mH inductance. The 8 kHz switching-frequency rating tells you this reactor is built for modern IGBT drives — it will handle the dv/dt and circulating currents at common carrier frequencies up to that point. Power loss splits 500W in the coil and 299W in the iron core at rated load (799W total), so panel ventilation matters; that heat has to leave the enclosure. Thermal class H (IEC 60085) means the winding insulation handles 180°C hot-spot — adequate for the 40°C ambient rating with the expected temperature rise. IP23 protection — the enclosure keeps out solid objects over 12 mm and dripping water at up to 60° from vertical. That's fine for a dry, ventilated cabinet but not for washdown areas or outdoor installation without a weather hood. Connections are flat connector / screw-type terminals, so expect lug-style terminations on the main circuit.
Where this class of part is used
Output reactors sit between a variable-frequency drive and the motor. They smooth the PWM waveform, limit the rate of voltage rise (dv/dt) at the motor terminals, reduce bearing currents, and extend cable runs. Any 3-phase induction motor on a VFD benefits from one, especially with long motor cables or multiple motors on a single drive.