Braze end isolation layer for generator armature winding bar and method for applying the isolation layer

• US 20060108401A1
• Filed: 11/19/2004
• Published: 05/25/2006
• Est. Priority Date: 11/19/2004
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Breznak, Jeffrey Michael, Hopeck, James Fredrick, Sowers, Lawrence Lee, Iversen, Alan Michael
• Granted Patent: US 7,219,827 B2
• Time in Patent Office: Days
• US Class Current: 228/244
• CPC Class Codes: B23K 1/0008 specially adapted for particular articles or work
• CPC Class Codes: B23K 35/3006 Ag as the principal constituent
• 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 3/22 consisting of hollow conductors
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A brazed joint between an armature winding bar strand package and a hydraulic header clip end fitting including: a plurality of solid strands and a plurality of hollow strands arranged in a tiered array and forming the strand package, the plurality of hollow strands having free ends that extend axially beyond corresponding free ends of solid strands; a cavity in the end fitting into which extents the free ends of the hollow strands and solid strands, and an essentially phosphorous-free silver braze alloy joining the free ends of the plurality of hollow strands and said corresponding free ends of solid strands to each other and to interior surfaces of the end fitting, wherein said braze alloy forms an isolation layer over the free ends of the solid strands.

Claims

1. A brazed joint between an armature winding bar strand package and a hydraulic header clip end fitting comprising:

a plurality of solid strands and a plurality of hollow strands arranged in a tiered array and forming the strand package, said plurality of hollow strands having free ends that extend axially beyond corresponding free ends of said solid strands;

a cavity in the end fitting, said free ends of said plurality of hollow strands and said corresponding free ends of said solid strands extending to said cavity, and an essentially phosphorous-free silver braze alloy joining said free ends of said plurality of hollow strands and said corresponding free ends of said plurality of solid strands to each other and to interior surfaces of said end fitting, wherein said braze alloy forms an isolation layer over the free ends of said solid strands.

2. The brazed joint of claim 1 wherein said braze alloy covers said free ends of said solid strands to a depth of at least 0.010 inch.

3. The brazed joint of claim 1 wherein said plurality of hollow strands extend through the braze alloy isolation layer.

4. The brazed joint of claim 3 wherein said free ends of the plurality of hollow strands are open to said cavity.

5. The brazed joint of claim 1 wherein said plurality of solid and hollow strands are composed of at least one of copper, copper-nickel alloys and stainless steel.

6. The brazed joint of claim 1 wherein said free ends of the hollow strands are tiered rows axially longer than rows of said free ends of the solid strands.

7. A brazed joint between an armature bar and a hydraulic header clip comprising:

a cavity in the end fitting, accessed by an opening;

an array of solid and hollow strands received in said opening and arranged in a tiered array; and

an essentially phosphorous-free braze alloy joining said solid and hollow strands to each other and to internal surfaces of said end fitting, said braze alloy covering free ends of said solid strands and leaving free ends of said hollow strands open and unobstructed.

8. The brazed joint of claim 7 wherein said solid strands are arranged in rows and the hollow strands are arranged in rows.

9. The brazed joint of claim 8 wherein the rows of hollow strands extend axially beyond the rows of solid strands.

10. The brazed joint of claim 7 wherein said plurality of solid and hollow strands are composed of at least one of copper, copper-nickel alloys and stainless steel.

11. The brazed joint of claim 7 wherein said alloy covers the free ends of said solid strands is at least 0.010 inch.

12. A method of forming a brazed joint between an armature bar and a hydraulic header clip comprising:

a) locating ends of a plurality of hollow strands and a plurality of solid strands within a cavity in an end fitting such that free ends of said hollow strands extend axially beyond free ends of said solid strands; and

b) pre-placing an essentially phosphorous-free silver braze alloy around and between said ends of said hollow strands and said solid strands such that said braze alloy extends axially beyond the free ends of said solid strands.

13. The method of claim 12 and further comprising:

c) brazing the plurality of hollow and solid strands to the end fitting within a chamber in a controlled gas atmosphere.

14. The method of claim 12 wherein said pre-placed braze alloy extend no further than the free ends of the hollow strands.

15. The method of claim 12 wherein said braze alloy comprises strips of braze alloy interleaved between the strands.

16. The method of claim 12 wherein said plurality of solid and hollow strands are composed of at least one of copper, copper-nickel alloys and stainless steel

17. The method of claim 12 wherein said plurality of solid strands are composed of copper and hollow strands are composed of stainless steel.

18. The method of claim 12 wherein said free ends of the hollow ends extends at least 0.31 inch beyond the free ends of the solid ends.

19. The method of claim 12 wherein said alloy covers the free ends of said solid strands is at least 0.010 inch

21. The brazed joint of claim 19 wherein said braze alloy extends no further than free ends of the hollow strands.

20. A pre-braze assembly of an armature bar strand package and a hydraulic header clip comprising:

a plurality of hollow and solid strands arranged in a tiered array and forming the strand package;

a cavity in the end fitting, free ends of said plurality of strands extending through said opening and received in said cavity; and

an essentially phosphorous-free braze alloy interleaved between the strands and extending beyond said free ends of said plurality of solid strands.