Method for manufacturing and amorphous metal core for a transformer that includes steps for reducing core loss

• US 5,134,771 A
• Filed: 07/05/1991
• Issued: 08/04/1992
• Est. Priority Date: 07/05/1991
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Harris, W. C., Lee, Albert C.
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US07/726,239
• Time in Patent Office: 396 Days
• Field of Search: 29/609, 29/605, 29/606, 336/213, 336/217, 336/234
• US Class Current: 29/609
• CPC Class Codes: H01F 27/25 made from strips or ribbons H01F27/26 takes precedence
• CPC Class Codes: H01F 41/0226 from amorphous ribbons
• CPC Class Codes: Y10T 29/49073 by assembling coil and core
• CPC Class Codes: Y10T 29/49078 Laminated

Abstract

In this method of manufacturing an amorphous metal transformer core, there is provided a core form that comprises sections of amorphous metal strip wrapped about the core window, the strip sections having edges at laterally opposite sides thereof and the core form having at its laterally opposed sides a pair of faces where the edges of the strip sections are located. This core form is subjected to an annealing operation to relieve stresses therein. Then, the strip sections are displaced with respect to each other in a first lateral direction to develop a telescoping relationship between juxtaposed strip sections that disrupts short circuiting adhesions between juxtaposed strip sections that had developed during the annealing step. Thereafter, the strip sections are returned in a lateral direction opposite to the first lateral direction to restore their edges to substantially their normal, or original, positions.

Disrupting the short circuiting adhesions results in reduced core loss in the final product, i.e., an amorphous metal transformer core.

Claims

1. A method of manufacturing a core for an amorphous metal transformer comprising:

(a) providing a core form that includes a window and comprises sections of amorphous metal strip wrapped about said window, the strip sections having edges at laterally opposite sides thereof and the core form having at laterally-opposed sides of the core form a pair of faces where the edges of the strip sections are located,

(b) annealing said core form to relieve stresses therein,

(c) after said annealing step, displacing said strip sections laterally with respect to juxtaposed ones of said strip sections to develop a telescoping relationship between juxtaposed strip sections that disrupts short-circuiting adhesions between said juxtaposed strip sections that had developed during said annealing step, said displacing step moving the edges of said strip sections laterally from normal positions, and

(d) thereafter returning said strip sections laterally to positions that restore their edges to substantially said normal positions.

2. A method as defined in claim 1 and further comprising:

controlling said laterally displacement of said strip sections by providing at least one wedge member adjacent one face of said core form, the wedge member having an inclined surface that is positioned to limit lateral motion of said strip sections with respect to each other the inclined surface being so located that there is a gap of varying length between said inclined surface and said one face immediately prior to said displacement step.

3. A method as defined in claim 1 and further comprising:

controlling said lateral displacement of said strip sections by providing a plurality of spaced-apart wedge members adjacent one face of said core form, each wedge member having an inclined surface that is positioned to limit lateral motion of said strip sections with respect to each other, said inclined surface being so located that there is gap of varying length between said inclined surface and said one face immediately prior to said displacement step.

4. A method as defined in claim 1 and further comprising:

controlling said lateral displacement of said strip sections by positioning said core form so that the central axis of said window is generally vertical and one face of said core form is seated on at least one wedge member, said wedge member having an inclined surface onto which the edges of said strip sections at said one face of said core member fall when said core member is positioned on said wedge member with said window axis generally vertical, thereby effecting said lateral displacement of said strip sections.

5. A method as defined in claim 1 and further comprising:

controlling said lateral displacement of said strip sections by positioning said core from so that the central axis of said window is generally vertical and one face of said core form is seated on a plurality of spaced-apart wedge members, each wedge member having an inclined surface onto which the edges of said strip sections at said one face of said core member are displaced when said core member is positioned on said wedge members with said window axis generally vertical, thereby effecting said lateral displacement of said strip sections.

6. A method as defined in claim 1 and further comprising controlling said lateral displacement of said strip sections by forcing against one face of said core form a wedge member that has an inclined surface abutting the edges of said strip sections.

8. A method as defined in claim 1 and further comprising:

(a) after said annealing step, applying to one of said faces an adhesive coating that requires time for curing following application, and

(b) causing said strip-section displacing step and said strip-section restoring step to be carried out after said coating has been applied to said one face but before full curing of said coating has occurred.

9. A method as defined in claim 1 and further comprising:

(a) after said annealing step, applying to said faces of the core form adhesive coatings that require time for curing following application, and

(b) causing the strip-section displacing and restoring steps of (c) and (d), claim I, to be carried out after said coatings have been applied to said faces but before full curing of said coatings has occurred.

10. A method as defined in claim 1 and further comprising:

(a) abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(b) causing said abrading step to be carried out after said annealing step but before said strip-section displacing step.

11. A method as defined in claim 2 and further comprising:

(a) abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(b) causing said abrading step to be carried out after said annealing step but before said strip-section displacing step.

12. A method as defined in claim 8 and further comprising:

(a) after said annealing step, abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(b) causing said coating-applying step to be carried out with respect to said one face of said core form after said abrading step has been carried out with respect to said one face of said core form.

13. A method as defined in claim 9 and further comprising:

(a) after said annealing step, abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(b) causing said abrading step to be carried out before said adhesive coatings are applied.

14. A method as defined in claim 1 in which before said annealing step, said core form is subjected to an edge-aligning operation that forces the edges of said strip sections to be substantially aligned at each face of said core form.

15. A method as defined in claim 2 in which before said annealing step, said core form is subjected to an edge-aligning operation that forces the edges of said strip sections to be substantially aligned at each face of said core form.

16. The method of claim 1 in which said strip sections are discrete lengths of amorphous metal strip that extend about said core window and have ends meeting in a joint region of the core.

17. The method of claim 1 in which said core form is an uncut core form in which amorphous metal strip material extends uninterrupted for many turns about said window.

18. A method as defined in claim 1 and further comprising:

after said annealing step, abrading the faces of said core form to remove projecting edges of the amorphous metal strip sections from said faces thereby disrupting externally-located adhesions formed by said projecting edges between juxtaposed strip sections.

19. A method as defined in claim 2 and further comprising:

after said annealing step, abrading the faces of said core form to remove projecting edges of the amorphous metal strip sections from said faces thereby disrupting externally-located adhesions formed by said projecting edges between juxtaposed strip sections.

25. The method of claim 2 in which the inclined face of said one wedge member extends across the entire build of said core form in such a manner that said gap is of increasing length, proceeding from one periphery to the other of said core form.

26. The method of claim 2 in which the inclined face of a said one wedge member has a V or U shaped configuration.

7. A method as defined in claim and further comprising controlling said lateral displacement of said strip sections by forcing against one face of said core form two spaced-apart wedge members, each having an inclined surface abutting the edges of said strip sections.

20. A method of manufacturing a core for an amorphous metal transformer comprising:

(a) providing a core form that includes a window and comprises sections of amorphous metal strip wrapped about said window, the strip sections having edges at laterally opposite sides thereof and the core form having at laterally-opposed sides of the core form a pair of faces where the edges of the strip sections are located,

(b) annealing said core form to relieve stresses therein,

(c) after said annealing step, disrupting short-circuiting internal adhesions between juxtaposed strip sections that had developed during said annealing step by a procedure that subjects said adhesions to disruptive force of such a character that it causes relative movement between juxtaposed strip sections without cracking or shattering the strip sections,

(d) abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(e causing said abrading step to be carried out after said annealing step but before said adhesion-disrupting step of (c), hereinabove.

22. A method as defined in claim 21 and further comprising:

(a) abrading the faces of said core form to remove projecting edges of the amorphous strip sections therefrom, and

(b) causing said abrading step to be carried out after said annealing step but before said adhesion-disrupting step of (c), claim 20.

21. A method of manufacturing a core for an amorphous metal transformer comprising:

(a) providing a core form that includes a window and comprises sections of amorphous metal strip wrapped about said window, the strip sections having edges at laterally opposite sides thereof and the core form having at laterally-opposed sides of the core form a pair of faces where the edges of the strip sections are located,

(b) annealing said core form to relieve stresses therein,

(c) after said annealing step, temporarily forcing juxtaposed strip sections apart by applying to one of said faces a blast of gas that flows from said one face to the other face by paths extending between juxtaposed strip sections and acts to disrupt short-circuiting adhesions in the zone of said core form traversed by said air blast, and

(d) moving said blast of gas over the exposed surface of said one face so as to subject the adhesions in additional core zones to the disrupting action of said air blast.

23. A method as defined in claim I in which:

(a) step (c) of claim displaces said strip sections laterally with respect to juxtaposed ones of said strip sections in a first lateral direction from said normal positions, and

(b) said core form is subjected to a second telescoping action following step (c) of claim that displaces said strip sections laterally in a second lateral direction from said normal positions that is opposite to said first lateral direction.

24. A method as defined in claim 23 and further comprising:

(a) controlling said lateral displacement of said strip sections in said first lateral direction by providing at least one wedge member adjacent one face of said core form, the wedge member having an inclined surface that is positioned to limit lateral motion of said strip sections with respect to each other in said first lateral direction, and

(b) controlling said lateral displacement of said strip sections in said second lateral direction by providing at least one wedge member adjacent the opposite face of said core form, said latter wedge member having an inclined surface that is positioned to limit lateral motion of said strip sections with respect to each other in said second lateral direction.