Powder coating for generator stator bar end fitting and method for applying the powder coating

• US 7,150,091 B2
• Filed: 11/09/2004
• Issued: 12/19/2006
• Est. Priority Date: 11/09/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wang, Yu, Lusted, Roderick Mark, Mall, Waheed Tony
• Primary Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US10/983,673
• Publication Number:
  US 20060102702A1
• Time in Patent Office: 770 Days
• Field of Search: None
• US Class Current: 29/596
• CPC Class Codes: H02K 15/0093 Manufacturing or repairing cooling fluid boxes, i.e. terminals of fluid cooled windings ensuring both electrical and fluid connection
• CPC Class Codes: H02K 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 3/44 Protection against moisture or chemical attack; Windings specially adapted for operation in liquid or gas
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A method of sealing a generator stator bar and a stator bar end fitting receiving the end including the steps of: brazing the fitting to the end of the stator bar with a braze material; applying a powder coating material to the end of the stator bar in the fitting; and curing the powder coating material to form a barrier coating on the end of the stator bar and the adjoining interior surfaces of the fitting.

Claims

1. A method of sealing the junction of a generator stator bar end and a stator bar end fitting receiving the bar, comprising:

attaching the fitting to the end of the stator bar with a braze material;

applying a powder coating material at least to the end of the stator bar attached to the fitting, through a chamber in the fitting; and

curing the powder coating material to form a barrier coating on the end of the stator bar and the adjoining interior surfaces of the fitting,

wherein said applying comprises electrostatically charging the powder coating material and spraying said powder coating material into said chamber.

2. The method as in claim 1, wherein said curing includes heating the fitting.

3. The method as in claim 1, wherein attaching the fitting comprises brazing the fitting and stator bar with a phosphorous copper braze alloy and the powder coating material comprises a thermosetting epoxy.

4. The method as in claim 1, wherein the fitting comprises a stator bar clip.

10. The method as in claim 1, wherein said powder coating material comprises a polymer.

5. A method of sealing a stator bar end to a stator bar clip, the clip having a chamber for receiving a liquid through an opening and in communication with hollow strands in said stator bar to enable coolant liquid flow through the hollow strands, said method comprising:

brazing the clip to the end of the stator bar;

electrostatically charging a powder coating material and spraying said powder coating material into said chamber; and

curing the powder coating material to form a barrier over the end of the stator bar in the fitting.

6. The method as in claim 5, wherein said curing includes heating the fitting.

7. The method as in claim 5, wherein said stator bar further comprises solid strands and said hollow strands extend into said chamber a distance greater than said solid strands.

8. The method of claim 5, wherein brazing the clip comprises brazing the clip and stator bar with a phosphorous copper braze alloy and the coating material comprises a thermosetting epoxy.

11. The method as in claim 5, wherein said powder coating material comprises a polymer.

9. A method of coating the interior of a stator bar clip including the steps of electrically grounding the stator bar clip, spraying an electrostatically charged powder into the stator bar clip to form a layer of the powder thereon to a predetermined thickness and curing the powder spray-coated on the stator bar clip to form a substantially continuous corrosion barrier layer on an exposed interior surface thereof.

12. The method as in claim 9, wherein said powder coating material comprises a polymer.

13. The method as in claim 9, wherein said curing includes heating the stator bar clip.