Impregnated high voltage spacers for use with resin filled hose bracing systems

• US 4,367,425 A
• Filed: 06/01/1981
• Issued: 01/04/1983
• Est. Priority Date: 06/01/1981
• Status: Expired due to Fees

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Navish, Francis W. Jr., Mendelsohn, Morris A.
• Primary Examiner(s): Lieberman, Paul
• Assistant Examiner(s): Sellers, Robert E. L.
• Application Number:
  US06/269,133
• Time in Patent Office: 582 Days
• Field of Search: 310/260, 525/123, 525/127, 525/131, 525/126
• US Class Current: 310/260
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 31/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid of hydrolysed polymers C08L29/00; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 31/06 Homopolymers or copolymers of esters of polycarboxylic acids
• CPC Class Codes: C08L 31/08 of phthalic acid
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: H02K 2203/09 Machines characterised by wiring elements other than wires, e.g. bus rings, for connecting the winding terminations
• CPC Class Codes: H02K 3/505 for large machine windings, e.g. bar windings H02K3/51 takes precedence
• CPC Class Codes: Y10S 174/20 Stator

Abstract

A compatible, gellable, dual resin system useful for impregnating porous spacers between stator end windings of turbine generators is made from (A) a liquid diallyl isophthalate component comprising an admixture of liquid diallyl isophthalate monomer and solid diallyl isophthalate prepolymer, where the weight ratio of monomer:prepolymer is between about 1.5:1 and about 3.0:1, (B) an amount of chain forming isocyanate terminated polyurethane prepolymer effective to provide a chain network which physically interpenetrates the liquid diallyl isophthalate component, and prevents free flow of liquid diallyl isophthalate component, (C) a chain extender for the isocyanate terminated polyurethane prepolymer, and (D) a catalyst for the diallyl isophthalate component, where the resin system is curable with the application of heat.

Claims

1. A fluid, gellable resin system impregnated into a porous substrate, said substrate being disposed between stator conductor coils in the end winding area of an electrical apparatus, wherein said resin system consists essentially of:

(A) a liquid diallyl isophthalate mixture comprising the admixture of liquid diallyl isophthalate monomer and solid diallyl isophthalate prepolymer, where the ratio of monomer;

prepolymer is between about 1.5;

1 and about 3.0;

1,

(B) an amount of isocyanate terminated polyurethane prepolymer effective to provide between about 0.010 and about 0.020 equivalent of NCO group per 100 grams of liquid diallyl isophthalate mixture, where the isocyanate component is selected from the group consisting of 2,4-tolylene diisocyanate;

2,6-tolylene diisocyanate;

mixtures of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; and

4,4'"'"'-diphenyl methane diisocyanate,

(C) a chain extender for the isocyanate terminated polyurethane prepolymer consisting of trimethylene glycol di-p-aminobenzoate when the isocyanate component contains tolylene diisocyanate; and

selected from hydroquinone di-(β

-hydroxyethyl) ether;

ethylene glycol;

1,2-propanediol;

1,3-propanediol;

1,5-pentanediol;

1,4-butanediol;

1,3-butanediol;

1,2-butanediol;

2,2-butanediol;

2,3-butanediol, mixtures thereof, and mixtures with triols when the isocyanate component contains 4,4'"'"'-diphenyl methane diisocyanate, and

(D) a peroxide catalyst for the liquid diallyl isophthalate mixture, where the resin system is curable with the application of heat.

2. The resin system of claim 1, where the resin is characterized as having the properties of a viscosity of up to about 120 stokes at 25°

C. after 3 hours, no resin runout from the substrate after 3 weeks when cured at 125°

C., and a heat distortion temperature upon cure of over about 200°

C.

4. The resin system of claim 1, where the solid diallyl isophthalate prepolymer has a weight average molecular weight of between about 200,000 and about 300,000, and contains unreacted pendant allyl groups, and where the weight ratio of diallyl isophthalate monomer:

prepolymer is between about 2.0;

1 and about 2.5;

1.

5. The resin system of claim 1, where the isocyanate terminated polyurethane prepolymer is present in an amount effective to provide between about 0.010 and about 0.020 equivalent of NCO group per 100 grams of liquid diallyl isophthalate mixture, and the isocyanate terminated prepolymer has a weight average molecular weight of between about 700 and about 2,500.

3. A stator end winding spacer system, located in the end winding section of an electrical apparatus, comprising spacers disposed between a plurality of stator end winding conductor coils, said spacers having impregnated therein a cured resin system comprising the admixture of:

(A) a liquid diallyl isophthalate mixture comprising the admixture of liquid diallyl isophthalate monomer and solid diallyl isophthalate prepolymer, where the weight ratio of monomer;

prepolymer is between about 1.5;

1 and about 3.0;

1,

(B) an amount of chain forming isocyanate terminated polyurethane prepolymer effective to provide a chain network which physically interpenetrates the liquid diallyl isophthalate mixture and prevents free flow of the liquid diallyl isophthalate mixture,

(C) a chain extender for the isocyanate terminated polyurethane prepolymer, and

(D) a catalyst for the liquid diallyl isophthalate mixture, where the resin system is curable with the application of heat.