Filters for adjustable speed drives with low DC bus capacitance and methods of manufacture and use thereof

A method, comprising:

• utilizing a drive filter between a three-phase alternative current power source and an adjustable speed drive;
• wherein the drive filter comprises:
• a plurality of input contacts configured for receiving an initial three-phase alternative current from the three-phase alternative current power source;
• a plurality of output contacts configured for outputting an output current to a respective phase of the adjustable speed drive;
• a plurality of electrical connections, wherein each electrical connection is configured to connect each input contact of the plurality of input contacts to a respective output contact of the plurality of output contacts;
• wherein each of the plurality of electrical connections consists of an electrical component;
• wherein the electrical component is selected from the group consisting of:
• i) one or more line capacitors and
• ii) the one or more line capacitors and one or more resistors;
• and
• wherein the drive filter further comprises:
• an inductor assembly comprising:
• a first core element having a first core bridge from one side of which extend first, second and third legs each having a remote end;
• a second core element having a second core bridge from one side of which extend fourth, fifth and sixth legs each having a remote end, wherein the second core bridge is adjacent to and spaced from the remote ends of the first, second and third legs thereby being magnetically coupled to the first core element;
• a third core bridge spaced from and extending across the fourth, fifth and sixth legs thereby being magnetically coupled to the second core element;
• and
• first, second, third, fourth, fifth and sixth electrical coils each wound around a different one of the first, second, third, fourth, fifth and sixth legs and coupled between the plurality of input contacts and the plurality of output contacts;
• and
• wherein the current flowing from the input contacts to the output contacts upon passing through the first, second, and third electrical coils produces magnetic flux that flows through the second core bridge in an opposite direction to magnetic flux produced by that current passing through the fourth, fifth and sixth electrical coils, which results in a magnetic flux within the second core bridge that is less than a sum of the magnetic fluxes in each of the first, second, third, fourth, fifth and sixth legs.