# US 5,710,475 A · Insulation of high thermal conductivity and apparatus containing same

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- Number: US 5,710,475 A
- Document ID: US5710475A
- Status: Granted
- Kind: A
- Application number: 08/561,997
- Filed: 1995-11-22
- Granted: 1998-01-20
- Earliest claimed: 1995-11-22
- Assignees: General Electric Company
- Inventors: Patricia Chapman Irwin; Charles Edward Baumgartner; Donald Allen Bolon
- Web page: https://patentgrep.com/patent/US5710475A

## CPC

- B32B 27/18: characterised by the use of special additives
- B32B 27/20: using fillers, pigments, thixotroping agents
- H01B 3/306: {Polyimides or polyesterimides}
- H01B 3/307: {Other macromolecular compounds}
- H02K 3/30: Windings characterised by the insulating material
- B32B 2264/10: Inorganic particles
- B32B 2307/302: Conductive
- B32B 2457/00: Electrical equipment
- H02K 9/223: {Heat bridges}
- Y10T 428/294: including metal or compound thereof [excluding glass, ceramic and asbestos]
- Y10T 428/31681: Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
- Y10T 428/31721: Of polyimide
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## 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

### Claim 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.degree.K at 180.degree. C.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 2)

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

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 4)

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

### Claim 6 (depends on 1)

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

### Claim 7 (depends on 6)

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

### Claim 8 (depends on 6)

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

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 1)

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