High-power, low-loss high-frequency electrical coil

• US 3,946,349 A
• Filed: 08/03/1973
• Issued: 03/23/1976
• Est. Priority Date: 05/03/1971
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Haldeman, Charles W. III
• Primary Examiner(s): Kozma, Thomas J.
• Application Number:
  US05/385,363
• Time in Patent Office: 963 Days
• Field of Search: 336/62, 336/60, 336/55, 336/96, 336/205, 336/222, 174/15 C, 174/114 R, 219/10.79, 29/605, 264/317, 260/33.4 P
• US Class Current: 336/62
• CPC Class Codes: H01F 17/00 Fixed inductances of the signal type coils in general H01F5/00; inductors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof and multistep manufacturing processes therefor H01L28/10
• CPC Class Codes: H01F 27/10 Liquid cooling
• CPC Class Codes: H01F 30/08 without magnetic core
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

High frequency electrical coils are commonly made out of Litz wire. If the coil is baked and an aqueous phenol solution is pumped through a nylon tube making up the structural core of the Litz wire, the tube will be dissolved out, thereby yielding an unobstructed opening through which a cooling fluid may be pumped. The resultant coil has a vastly improved heat conduction and can tolerate substantially higher currents.

Claims

1. An improved high-power, low-loss, high-frequency electrical coil comprising:

a. at least one turn of Litz wire having a clear unobstructed center channel through which a cooling fluid may be pumped, there being no element between said Litz wire and said center channel, said wire being wound in a circular pattern,

b. an electrical insulating material with mechanical strength in which the Litz wire is imbedded.

2. An improved high-power, low-loss, high-frequency electrical coil as recited in claim 1 in which said insulating material comprises a plastic resin.

3. An improved high-power, low-loss, high-frequency electrical coil as recited in claim 1 including means for making an electrical connection to said coil.

4. An improved high-power, low-loss, high-frequency electrical coil as recited in claim 1 including means for making a hydraulic connection to said unobstructed hollow center channel through which a cooling fluid may be pumped through said center channel.

5. An improved high-power, low-loss, high-frequency electrical conductor that comprises a Litz wire having an unobstructed hollow center channel with no element between said Litz wire and said hollow center channel, and a low-electrical-loss, high-dielectric insulating cover that provides a structurally sound housing to prevent collapse of the otherwise structurally unstable Litz wire.

6. An electrical conductor as claimed in claim 5 in which the insulating cover comprises a plastic material which impregnates the outer surface of the conductor, the wires at said outer surface being imbedded in the plastic material which provides the necessary mechanical strength to prevent collapse inwardly of the Litz wire and to provide a liquid impervious structure around and between the outer wires of the Litz wire, thereby to permit a cooling fluid to be pumped through said channel to be in intimate thermal contact with the individual current-carrying wires making up the Litz wire.

7. An electrical conductor as claimed in claim 6 that includes a compression fitting at either end thereof to serve as an electrical terminal and as a hydraulic connector.

8. An electrical conductor as claimed in claim 6 in which said plastic is an epoxy material.

9. An electrical conductor as claimed in claim 6 in which said plastic is a polystyrene material.

10. An electrical conductor as claimed in claim 6 in which said plastic is a silicone rubber material.