A power conditioning circuit for conditioning power supplied by a power source at a nominal frequency over conductors in a polyphase system includes first and second phase conductors. First and second inductors are connected in series between the first and second phase conductors and first and second phase output lines, wherein all of the power supplied by the power source to the first and second phase output lines flows through the first and second inductors. An inductance of each of the first and second inductors increases when power at frequencies greater than the nominal frequency flows through the first and second phase conductors, thereby blocking power at frequencies greater than the nominal frequency from reaching the first and second phase output lines.