Method for repairing stator winding bars

• US 5,557,837 A
• Filed: 04/03/1995
• Issued: 09/24/1996
• Est. Priority Date: 01/26/1995
• Status: Expired due to Term

• Current Assignee: Alstom SA
• Original Assignee: ABB Management AG (ABB Limited)
• Inventors: Thiard-Laforet, Alfred, Zerlik, Wilibald
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US08/415,362
• Time in Patent Office: 540 Days
• Field of Search: 29/596, 29/598, 29/402.08, 29/402.16, 310/54, 310/59, 310/60, 228/165, 228/170
• 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 3/505 for large machine windings, e.g. bar windings H02K3/51 takes precedence
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/4973 Replacing of defective part
• CPC Class Codes: Y10T 29/49742 Metallurgically attaching preform

Abstract

The method for repairing a connecting device for the electrical connection and for supplying and carrying away the coolant to and from the hollow conductor elements of the stator winding bars of electrical machines includes removal of the existing connecting device (2) from the bar end by inductive heating; cleaning the bar end in the region where the new connecting device is intended to be mounted; material-cutting machining the end surface of the bar end; introducing narrow slots (7) between adjacent conductor elements (1) into the end of the bar in the transverse and vertical directions; pushing on a first connecting part (2a) which is made of copper and completely surrounds the bar end; filling remaining gaps between the first connecting part (2a) and the outer surfaces of the bar end with copper foil and/or solder foil; filling the narrow slots (7) with copper foil and/or solder foil (10) or a combination of both; inductive heating of the first connecting part (2a) and of the bar end and soldering with the addition of solder; inspecting the solder joint thus created; fitting a second connecting part (2b) made of copper to the free end surface of the first connecting part (2a) by soldering; and testing the sealing of the resulting connecting device (2a,2b).

Claims

1. A method for repairing a connecting device for the electrical connection and for supplying and carrying away the coolant to and from the conductor elements of the stator winding bars of electrical machines, at least some of said conductor elements being hollow, all the conductor elements being surrounded by a metallic component and being soldered thereto and to one another, which component overhangs the conductor elements forming a water chamber and ends in a connecting fitting for coolant supply and carrying the coolant away, comprising the following method steps:

a) inductive heating and removal of the existing connecting device from the bar end;

b) cleaning the bar end in the region where the new connecting device is intended to be mounted;

c) material-cutting machining the end surface of the bar end;

d) introducing narrow slots between adjacent conductor elements into the end of the bar in the transverse direction and vertical direction;

e) pushing on a first connecting part which is made of copper and completely surrounds the bar end;

f) filling remaining gaps between the first connecting part and the outer surfaces of the bar end with copper foil and/or solder foil;

g) filling the narrow slots, which have been introduced into the end of the bar, with copper foil and/or solder foil or a combination of both;

h) inductive heating of the first connecting part and of the bar end and soldering with the addition of solder;

i) at least visual inspection of the solder joint thus created;

j) fitting a second connecting part made of copper to the free end surface of the first connecting part by soldering;

k) testing the sealing of the resulting connecting device.

2. The method as claimed in claim 1, wherein the slots which are introduced between the conductor elements are filled with strips which have a central copper layer which is provided with solder foil on both sides.

3. The method as claimed in claim 1, wherein only solder foil is inserted into the said slots and the hollow ones of said conductor elements are then subsequently widened until adjacent hollow conductor elements touch at the edges, and wherein the remaining gaps are filled with copper pins at the points at which four hollow conductor elements meet.

4. The method as claimed in claim 3, wherein the remaining gaps are drilled in advance at the points at which four hollow conductor elements meet.