Electrical harmonic suppression system and enclosure for the same

An electrical system for supplying power to an adjustable speed drives, the electrical system comprising:

• a supply transformer selected from the group consisting of a delta-wye and wye-wye transformer, and having a wye secondary side with a Phase A line, a Phase B line, and a Phase C line,
• a supply line from the supply transformer to the adjustable speed drive, wherein the supply line comprises a pair of phase lines selected from the group consisting of a Phase A line/Phase B line pair, a Phase B line/Phase C line pair, and a Phase A line/Phase C line pair;
• and
• a completely-passive parallel resonant circuit being electrically connected in a single phase manner near the adjustable-speed drive to one phase line of the pair of phase lines of the supply line
• wherein the completely-passive parallel resonant circuit having three passive electrical branches connected in parallel,
• wherein the completely-passive parallel resonant circuit having an almost infinite impedance at a third harmonic frequency of a fundamental frequency of the supply transformer to prevent the formation of only the third harmonic frequency so that there is no third harmonic frequency to remove or dissipate as heat,
• wherein the three passive electrical branches comprise a first branch including a capacitor, a second branch including a reactor, and a third branch including a resistor,
• whereby the electrical system is rendered free of the third harmonic frequency in all phase lines, both toward the adjustable-speed drives and back to the supply transformer.