WINDING END TURN COOLING IN AN ELECTRIC MACHINE

• US 20090195092A1
• Filed: 01/31/2008
• Published: 08/06/2009
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: Gagnon, Gilles D.
• Granted Patent: US 8,198,762 B2
• Time in Patent Office: Days
• US Class Current: 310/54
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator

Abstract

Winding end turns in an electric machine are cooled by a coolant. Cooling is improved by redirecting the coolant generally tangentially through the winding end turns to improve heat transfer between coolant and windings.

Claims

1. A cooling apparatus for an electric machine having a plurality of winding end turns that are generally axisymmetric with respect to one another, the apparatus comprising:

a plurality of coolant input paths, each communicating with a source of coolant and defined between a corresponding pair of the winding end turns;

a plurality of internal coolant paths defined tangentially relative to the machine, each coolant input path substantially extending through a corresponding one of the winding end turns and communicating with a corresponding one of the coolant input paths; and

a plurality of coolant output paths, each communicating with a corresponding pair of the internal coolant paths.

2. The cooling apparatus as defined in claim 1, wherein the coolant input paths and the coolant output paths are generally radially extending with reference to a center of the machine.

3. The cooling apparatus as defined in claim 1, wherein the source of coolant includes an external coolant supply.

4. The cooling apparatus as defined in claim 3, wherein the coolant is a liquid.

5. The cooling apparatus as defined in claim 1, wherein the coolant from at least some of the coolant output paths is sent to a second area of the machine for cooling a second set of winding end turns, the cooling apparatus having second internal coolant paths through the winding end turns of the second area.

6. The cooling apparatus as defined in claim 1, wherein the cooling apparatus comprises a plurality of coolant guides located between the winding end turns.

7. The cooling apparatus as defined in claim 6, wherein the coolant guides include first and second guides alternately disposed between the winding end turns and projecting axially with reference to a central axis of the machine, each first coolant guide located at an end of a corresponding one of the coolant input paths, and each second coolant guide located at a beginning a corresponding one of the coolant output paths.

8. The cooling apparatus as defined in claim 7, wherein coolant guides are provided within a cover sealingly engaged against the machine and enclosing the winding end turns.

9. An apparatus for cooling radially-disposed winding end turns of an electric machine, the apparatus comprising:

means for distributing coolant between pairs of adjacently-disposed winding end turns formed by the winding end turns of the machine;

means for directing the coolant from between the pairs of winding end turns tangentially relative to a center of the machine through the corresponding winding end turns of each pair; and

means for redirecting the tangential flow of coolant exiting the winding end turns to an outlet.

10. The apparatus as defined in claim 9, wherein the means for distributing the coolant includes means for supplying the coolant from an external coolant supply.

11. The apparatus as defined in claim 10, wherein the means for directing the coolant include a splitter having guides interposed between the winding end turns.

12. The apparatus as defined in claim 10, further comprising means for sending the coolant to other winding end turns located in another area of the machine.

13. A method of circulating a coolant in an electric machine, the method comprising the continuous steps of:

(a) providing a coolant flow into a first set of interspaces defined between adjacent winding end turns in the machine;

(b) dividing the coolant flow into at least two branches, two said branches of the coolant flow being directed tangentially relative to the machine through one of the adjacent winding end turns; and

(c) collecting the coolant branches exiting said adjacent winding end turns in a second set of the interspaces defined by the winding end turns.

14. The method as defined in claim 13, further comprising:

directing the coolant collected in step (c) from a first location to a second location within the machine and repeating steps (a), (b) and (c) for winding end turns at the second location.

15. The method as defined in claim 14, wherein the coolant collected in step (c) at the second location is cooled before being provided for a new cycle at the first location in the machine.

16. The method as defined in claim 15, wherein the coolant flowing in the interspaces separating the winding end turns at the first location follows a generally radial direction that is opposite a generally radial direction of the coolant at the second location.