The Siemens 4EU5021-0AE10-0B is a Netzdrossel — a three-phase mains choke (line reactor) rated for 350 A continuous at 690 V AC, 50 Hz. Its 0.35 mH inductance with a 12.5% relative inductive voltage drop at rated current and frequency means it limits harmonic currents and smooths line-side transients for a 3-phase drive or converter input. The IP00 open-frame construction and flat-type main-circuit connectors suit it for installation inside a cabinet where the enclosure provides the environmental seal.
The 350 A continuous rating at 690 V AC sets the line-side current it can carry without saturating the core. That 12.5% voltage drop at rated current is the impedance the choke presents to the line — enough to attenuate common harmonics from a 6-pulse rectifier (typically 5th and 7th) without dropping excessive voltage under load. Thermal class H (180 °C insulation) means the winding can survive sustained overloads that would degrade a class F or B choke; the 40 °C ambient rating is the reference, and derating applies above that.
Deployment context
This choke mounts into a panel or enclosure via its frame — no DIN-rail clip, so plan for bolted installation. The flat connectors for the main circuit accept busbar or cable lugs; the IP00 rating means the cabinet must provide the ingress protection. It is sized for a 350 A drive line-up on a 690 V three-phase system, common in marine, mining, or heavy industrial installations where harmonic mitigation is required before the drive input.