The Siemens 4EU3921-4FA10-0A is a 3-phase commutating choke (also called a line reactor or converter choke) designed to sit between a converter and the AC mains or motor load. Its job is to limit current rise rates (di/dt) and reduce harmonic distortion, protecting the converter's semiconductors from switching stress and smoothing the DC link. Rated for 900 A continuous (1,000 A maximum) at 460 V AC, 0 to 60 Hz, with an inductance of 0.021 mH and a relative inductive voltage drop of 3% at rated current. Coil loss 530 W, iron core loss 230 W. Thermal class H, 40 °C ambient.
900 A continuous at 40 °C ambient; 1,000 A short-time maximum. 3% impedance. DC rated current 1,225.4 A. Flat-type terminals. Dimensions: 0.41 m width, 0.385 m height, 0.229 m depth.