Patent ID: 7839251

Claim:
Three-phase AC or two-phase DC choke arrangement of a frequency converter, comprising: a magnetic core with a plurality of phase specific pillars having phase specific windings wound there around or a plurality of branch specific pillars having branch specific windings wound therearound, wherein, the phase-specific windings of the AC choke arrangement or the branch-specific windings of the DC choke arrangement are adapted to filter difference-mode currents, and in which an additional pillar for damping common-mode currents is arranged in the magnetic core, characterized in that, the additional pillar is arranged without the phase-specific or branch-specific windings fitted around it, and is adapted to damp common-mode currents by means of a common-mode impedance formed by the additional pillar and the windings arranged around the phase-specific or branch-specific pillars, and a winding is arranged around the additional pillar and is adapted to form a small-signal level pulse in a line-to-earth short-circuit situation.