The Siemens 4EP3910-7AS30 is a Netzdrossel — a three-phase AC mains choke (line reactor) rated for 50 A maximum continuous current, 45 A nominal, at 500 V operating voltage. The open-frame IP00 design means it mounts inside a panel or enclosure; there's no housing for touch protection, so panel builders must account for clearance and separation from live parts.
The 50 A maximum and 45 A rated current define the thermal envelope for continuous motor-drive or converter input duty. The 3% voltage drop at rated current is the impedance the choke presents to smooth line transients and limit harmonic distortion.
It remains in the current Siemens SENTRON line reactor portfolio.
The footprint is 0.219 m wide by 0.179 m tall by 0.123 m deep. The IP00 rating means the winding and core are exposed — the enclosure must provide touch protection. Screw terminals accept conductors for the 50 A circuit.