The Siemens SIDAC 4EU4521-0CC18-0B is a 3-phase output reactor (output choke) rated for 153 A continuous current with 0.7 mH inductance per phase. It sits between a variable-frequency drive and the motor to limit the rate of voltage rise (dV/dt) and reduce motor bearing currents, especially on long cable runs. The 8 kHz switching frequency rating matches the typical IGBT carrier frequency of modern drives, so the core does not saturate under pulse-width-modulated waveforms. Total power loss is 1280 W — 780 W in the coil and 500 W in the iron core — which must be ventilated.
The 153 A continuous rating (Ithmax) governs the motor full-load current it can handle. For a 460 VAC drive, this supports motors roughly in the 100–125 hp range depending on service factor. The 0.7 mH inductance provides enough impedance to limit peak currents without excessive voltage drop at the motor terminals. Class H insulation (180 °C thermal class per IEC 60085) means the reactor can tolerate sustained high winding temperatures — important when the drive is running at full load in a warm cabinet. The ambient temperature rating of 40 °C is the reference; derate above that. Dimensions are 0.46 m wide by 0.43 m tall by 0.29 m deep. The flat-type terminals accept busbar or large cable lugs — not spring-cage or screw-clamp. Panel builders should plan for busbar connections and adequate clearance around the terminals for high-current cabling.
The paperwork for cross-border shipments is straightforward — the HS code for output reactors falls under 8504.50, and the IP00 rating means no special environmental compliance documentation beyond standard CE declaration of conformity.