Retention assembly for stator bar using shim with stator wedge and related method

Patent metadata

Field	Value
Publication number	US-2016359385-A1
Application number	US-201514729205-A
Country	US
Kind code	A1
Filing date	Jun 3, 2015
Priority date	Jun 3, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A retention assembly for retaining a plurality of elements in a stator slot of an electric machine is provided. The retention assembly may include a stator wedge fixedly positioned in a dovetail in the stator slot to retain the plurality of elements; a top ripple spring between the plurality of elements and the stator wedge; and at least one shim positioned between the stator wedge and a load bearing surface of the dovetail. A method may include compressing the stator wedge in the stator slot from a first position thereof relative to the dovetail of the stator slot, the compressing creating a gap between the stator wedge and the dovetail. A shim may be inserted in the gap; the compressing released such that the shim retains the stator wedge in a second position that is more compressed relative to the plurality of elements in the stator slot compared to the first position.

First claim

What is claimed is:

1 . A retention assembly for retaining a plurality of elements in a stator slot of an electric machine, the retention assembly comprising:
a stator wedge fixedly positioned in a dovetail in the stator slot to retain the plurality of elements against pressure of a ripple spring positioned between the plurality of elements and the stator wedge; and at least one shim positioned between the stator wedge and a load bearing surface of the dovetail.

2 . The retention assembly of claim 1 , wherein the plurality of elements includes a stator bar and a slot filler.

3 . The retention assembly of claim 1 , wherein the stator wedge includes a plurality of stator wedges and the shim includes a plurality of shims positioned along a length of the plurality of stator wedges.

4 . The retention assembly of claim 1 , wherein the dovetail includes a first groove and an opposing second groove, and the stator wedge is fixedly positioned in the first groove and the opposing second groove, and
wherein the shim includes a first shim between the stator wedge and a loading bearing surface of the first groove and a second shim between the stator wedge and a load bearing surface of the opposing second groove.

5 . The retention assembly of claim 4 , wherein the stator wedge includes a plurality of stator wedges, and the first shim includes a plurality of first shims positioned along a length of the plurality of stator wedges, and the opposing, second shim includes a plurality of opposing, second shims positioned along a length of the plurality of stator wedges.

6 . The retention assembly of claim 1 , wherein the stator wedge includes one of a cotton phenolic composite and an epoxy-glass laminate.

7 . The retention assembly of claim 1 , wherein the shim is made of a non-conductive material selected from the group consisting of: a phenolic material, a para-aramid synthetic material, a meta-aramid material and a rigid fiberglass material.

8 . The retention assembly of claim 1 , wherein the shim includes a layer of polytetraflouorethylene (PTFE) thereon.

9 . The retention assembly of claim 1 , further comprising an adhesive adhering an edge of the shim to at least one of the stator wedge and the stator slot.

10 . An electric machine comprising:
a stator core including a stator slot; a plurality of elements in the stator slot, the plurality of elements including a stator bar; a stator wedge fixedly positioned in a dovetail in the stator slot to retain the plurality of elements in the stator slot against pressure of a ripple spring positioned between the plurality of elements and the stator wedge; and at least one shim positioned between the stator wedge and a load bearing surface of the dovetail.

11 . The electric machine of claim 10 , wherein the dovetail includes a first groove and an opposing second groove, and the stator wedge is fixedly positioned in the first groove and the opposing second groove, and
wherein the shim includes a first shim between the stator wedge and a load bearing surface of the first groove and a second shim between the stator wedge and a load bearing surface of the opposing second groove.

12 . The electric machine of claim 11 , wherein the stator wedge includes a plurality of stator wedges, and the first shim includes a plurality of first shims positioned along a length of the plurality of stator wedges, and the opposing, second shim includes a plurality of opposing, second shims positioned along a length of the plurality of stator wedges.

13 . The electric machine of claim 10 , wherein the shim is made of a non-conductive material selected from the group consisting of: a phenolic material, a para-aramid synthetic material, a meta-aramid material and a rigid fiberglass material.

14 . The electric machine of claim 10 , wherein the shim includes a layer of polytetraflouorethylene (PTFE) thereon.

15 . The electric machine of claim 10 , further comprising an adhesive adhering an edge of the shim to at least one of the stator wedge and the stator slot.

16 . A method of tightening a retention assembly for retaining a plurality of elements in a stator slot of a stator core of an electric machine, the retention assembly including a stator wedge positioned in a dovetail of the stator slot, the method comprising:
compressing the stator wedge in the stator slot from a first position thereof relative to the dovetail of the stator slot, the compressing creating a gap between the stator wedge and the dovetail; inserting a shim in the gap; and releasing the compressing of the stator wedge such that the shim retains the stator wedge in a second position that is more compressed relative to the plurality of elements in the stator slot compared to the first position.

17 . The method of claim 16 , wherein the second position of the stator wedge relative to the stator core is more radially outward compared to the first position.

18 . The method of claim 16 , wherein the compressing includes using a ram configured to interact with an opposing side of the stator core from the stator wedge.

19 . The method of claim 16 , further comprising repeating the compressing, inserting and releasing for a plurality of stator wedges.

20 . A shim for a retention assembly for retaining a plurality of elements in a stator slot of an electric machine, the retention assembly including a stator wedge fixedly positioned in a dovetail in the stator slot to retain the plurality of elements, the shim comprising:
a layer of material positioned between the stator wedge and a load bearing surface of the dovetail.

21 . The shim of claim 20 , wherein the layer of material includes a non-conductive material selected from the group consisting of: a phenolic material, a para-aramid synthetic material, a meta-aramid material and a rigid fiberglass material.

22 . The shim of claim 20 , wherein the layer of material includes a layer of polytetraflouorethylene (PTFE) thereon.

23 . The shim of claim 20 , further comprising an adhesive adhering an edge of the layer of material to at least one of the stator wedge and the stator slot.

Assignees

• Gen Electric

Inventors

• Buskirk Eric Steven
• Brown Andrew Duane
• Grant James Jonathan
• Hebert Curtis Maurice
• Mancuso Benjamin Alber
• Martin Matthew Robert
• Powers Jessica Mary

Classifications

• H02K3/487 Primary

  Slot-closing devices · CPC title

• H02K1/16 Primary

  Stator cores with slots for windings · CPC title

• H02K15/021

  Magnetic cores · CPC title

• H02K15/13

  Applying slot closure means in the cores; Manufacture of slot closure means · CPC title

• H02K15/0018

  Electricity · mapped topic