Insulation of high thermal conductivity and apparatus containing same

• US 5,710,475 A
• Filed: 11/22/1995
• Issued: 01/20/1998
• Est. Priority Date: 11/22/1995
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Bolon, Donald Allen, Irwin, Patricia Chapman, Baumgartner, Charles Edward
• Primary Examiner(s): Nakarani, D. S.
• Application Number:
  US08/561,997
• Time in Patent Office: 790 Days
• Field of Search: 310/254, 174/120 SR, 428/379, 428/458, 428/450, 428/473.5, 524/404, 524/428
• US Class Current: 310/45
• CPC Class Codes: B32B 2264/10 Inorganic particles
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 27/18 characterised by the use of special additives
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: H01B 3/306 Polyimides or polyesterimides
• CPC Class Codes: H01B 3/307 Other macromolecular compounds
• CPC Class Codes: H02K 3/30 Windings characterised by the insulating material
• CPC Class Codes: H02K 9/223 Heat bridges
• CPC Class Codes: Y10T 428/294 including metal or compound thereof [excluding glass, ceramic and asbestos]
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31721 Of polyimide

Abstract

Metallic conductors of electricity, such as stator bars in turbine generators, are coated with an insulating composition comprising a high temperature-resistant thermoplastic resin, such as a polyimide or polyethersulfone, having uniformly dispersed therein boron nitride or aluminum nitride in a proportion effective to provide a high thermal conductivity. Boron nitride is preferred by reason of its extremely high thermal conductivity, viscosity-decreasing properties and other advantages.

Claims

1. A turbine generator comprising a plurality of stator bars, each of which is insulated with a coating of a composition comprising a high temperature-resistant thermoplastic resin which is a polyimide, polyphthalamide, polyetherketone, polysulfone, polydiorganosiloxane, polyestercarbonate or liquid crystalline polyester, having uniformly dispersed therein at least one nitride selected from the group consisting of boron nitride and aluminum nitride in a proportion effective to produce a thermal conductivity in said composition of at least 0.35 W/m°

K at 180°

C.

2. A generator according to claim 1 wherein the nitride is boron nitride.

3. A generator according to claim 2 wherein the proportion of boron nitride is about 5-55% by weight based on total constituents.

4. A generator according to claim 1 wherein the nitride is aluminum nitride.

5. A generator according to claim 4 wherein the proportion of aluminum nitride is about 20-55% by weight based on total constituents.

6. A generator according to claim 1 further comprising at least one other inorganic filler.

7. A generator according to claim 6 wherein said other filler is fumed silica.

8. A generator according to claim 6 wherein said other filler is fumed alumina.

9. A generator according to claim 1 wherein the thermoplastic resin is a polyetherimide.

10. A generator according to claim 1 wherein the thermoplastic resin is a polyphenylsulfone.