Integrated seal for internal cooling passage of laminated core for electric machine

Abstract

To provide an integrated seal for an internal cooling passage of a laminated core for an electric machine.SOLUTION: A stator is suitable for coating an insulation varnish or a resin in a vacuum pressurization impregnation process. The stator includes a plurality of conductive coils, and a coolant passage penetrating to the stator and extending. The coolant passage is sealed through a coolant passage seal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application and the resulting patent relate generally to electric machines such as motors and generators used in the production of electrical power, and more particularly to integrated sealing of cooling passages during application of insulating varnish and / or resin. [Background technology]

[0002] Typically, electric machines, such as motors and generators, used to produce electrical power may include a stator and a rotor. One or both of the stator and rotor may include conductive windings or coils therein. During the manufacture of an electric machine, insulating varnish and / or resin is applied to the stator using a vacuum pressure impregnation (VPI) process. In the VPI process, the varnish / resin is applied in liquid form, and a vacuum is applied to force the varnish / resin to penetrate and encapsulate the stator. The insulating varnish / resin can then be cured using a pressure process and a heat curing process. Both the vacuum and pressure aid in the penetration of the resin into the stator. Other types of resin application processes, such as dip coating, trickle varnish, etc., may also be used herein.

[0003] The overall power output of an electric machine can be limited by heat buildup in the rotor and / or stator components. Such heat buildup can be at least partially reduced by using different types of coolant flow. Specifically, high-power-density electric machines may require close proximity cooling for both core losses and armature coil losses. The use of internal coolant passages in the laminated stator core itself allows for efficient heat transfer. However, these coolant passages can be destroyed or damaged during the application of insulating varnish / resin, especially during subsequent machining steps to open the coolant passages. The coolant passages can become blocked or significantly reduced in size. Additionally, foreign debris can be a concern for the cooling system as a whole. Summary of the Invention

[0004] Thus, the present application and resulting patent provide a stator suitable for application of an insulating varnish or resin in a vacuum pressure impregnation process. The stator includes a plurality of conductive windings and a coolant passage extending therethrough. The coolant passage is sealed with a coolant passage seal.

[0005] The present application and resulting patent may further provide a method of manufacturing a stator for an electric machine, the method including drilling coolant passages through the stator, sealing the coolant passages with a coolant passage seal, applying an insulating varnish or resin to the stator in a vacuum pressure impregnation process, and removing the coolant passage seal from the coolant passages.

[0006] The present application and the resulting patent further provide an electric machine stator suitable for application of an insulating varnish or resin in a vacuum pressure impregnation process. The electric machine can include a rotor, a stator, a plurality of conductive windings in the stator, and a plurality of coolant passages extending through the stator. Each coolant passage is sealed with a coolant passage seal.

[0007] These and other features and improvements of the present application and the resulting patent will become apparent to those skilled in the art from a review of the following detailed description when taken in conjunction with the several drawings and the appended claims. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an electric machine having a stator and a rotor; [Figure 2] 2 is a further schematic diagram of an electric machine having coolant passages extending through the stator; [Figure 3] 1 is a schematic diagram of a coolant passageway closed by a thin lamination stack. [Figure 4] 4 is a further schematic view of the closed coolant passage of FIG. 3. [Figure 5] 4 is a schematic diagram of the closed coolant passage of FIG. 3 covered with insulating varnish / resin. [Figure 6] 4 is a schematic diagram of the coolant passage of FIG. 3 in an open state. [Figure 7] FIG. 7 is a further schematic view of the coolant passage of FIG. 6 in an open state. [Figure 8] FIG. 10 is a schematic diagram of coolant passages blocked by expanded core end rings. [Figure 9] 9 is a schematic view of the coolant passage of FIG. 8 in an open state. [Figure 10] FIG. 10 is a schematic diagram of a coolant passage closed by a sealing plug. [Figure 11] FIG. 11 is a schematic diagram of the coolant passage of FIG. 10 in an open state. [Figure 12] 1 is a schematic diagram of a coolant passage blocked by an expanded sealing plug; [Figure 13] FIG. 13 is a schematic diagram of the coolant passage of FIG. 12 in an open state. [Figure 14] FIG. 10 is a schematic diagram of a coolant passage closed by a threaded sealing plug. [Figure 15] FIG. 15 is a schematic diagram of the coolant passage of FIG. 14 in an open state. DETAILED DESCRIPTION OF THE INVENTION

[0009] Referring now to the drawings, wherein like numerals refer to like elements throughout the several views, FIG. 1 is a schematic diagram of an example of an electric machine 100. In general, electric machine 100 may be a motor 110, a generator 120, or the like. Electric machine 100 may include a stator 130 and a rotor 140. Stator 130 may include a stator frame 150 and a body 160 including a plurality of conductive windings 170 disposed on a magnetic core. (Alternatively, rotor 140 may include conductive windings about the magnetic core.) Rotor 140 may include a shaft 180 having a rotational axis RA. Stator 130 is disposed around rotor 140. Shaft 180 may be driven to rotate about rotational axis RA by, for example, a gas turbine, a steam turbine, a wind turbine, a hydroelectric turbine, an internal combustion engine, or any other suitable device configured to provide a rotational output. Shaft 180 is coupled to a substantially cylindrical body 190. Rotor 140 is disposed within stator 130 and configured to provide a stationary magnetic field. As described above, rotation of rotor 140 within stator 130 may generate current in conductive windings 170, thereby producing electrical output from electric machine 100. The electric machines described herein are for illustrative purposes only. Many different components and configurations may be used.

[0010] FIG. 2 is a simplified schematic diagram of the electric machine 100. In this example, multiple coolant passages 200 extend through the stator 130 adjacent the conductive windings 170. The coolant passages 200 may be drilled through the stator 130 using a laser cutting process or the like. The coolant passages 200 may have any suitable shape. Any number of coolant passages 200 may be used herein. Thus, the cooling flow 210 may enter the frame 150, pass through the cooling flow passages 200 adjacent the conductive windings 170, and exit through the other end of the stator 130 and frame 150. The cooling flow 210 may be any suitable medium. Suitable pumps, blowers, etc. may be used. In certain embodiments, the coolant passages may also be provided within the rotor 140.

[0011] FIGS. 3 and 4 show a portion of the stator 130 with respect to the coolant passages 200 before application of the insulating varnish / resin. The coolant passages 200 may be surrounded by a core end ring 220 or may be surrounded by a thin lamination stack 230 before VPI processing. FIG. 5 shows the application of the insulating varnish / resin 240 during VPI processing. Any type of conventional varnish / resin 240 may be used herein. FIGS. 6 and 7 show the open coolant passages 200 after VPI processing, where the insulating varnish / resin 240 and thin lamination stack 230 can be removed by conventional machining processes or the like. Any type of removal method may be used herein.

[0012] 8 and 9 illustrate the use of a coolant passage seal 250 as may be described herein. In this example, the coolant passage seal 250 may be an extended core end ring 260. As shown in FIG. 8, the extended core end ring 260 may extend the length of the stator 130 and enclose the coolant passage 200. The extended core end ring 260 may be applied to the stator 130 prior to the VPI treatment and application of the insulating varnish / resin 240. The extended core end ring 260 may be attached to the stator 130 via an O-ring 270 and adhesive 280 to seal the coolant passage 200. The O-ring 270 and adhesive 280 may be of conventional design. FIG. 9 illustrates an open coolant passage 200. The extended core end ring 260 may be removed, drilled, drilled, machined, or otherwise removed. Other components and configurations may be used herein.

[0013] 10 and 11 illustrate further examples of a coolant passage seal 250 as may be described herein. In this case, a seal plug 290 is shown in FIG. 10. The seal plug 290 may have a plug body 300 sized to fit with the core end ring 220 and the coolant passage 200. The seal plug 290 may have an O-ring 270 and adhesive 280 at one end of the plug body 300 relative to the coolant passage 200 and an extended flange 310 at the other end of the plug body 300 outside or adjacent the core end ring 220. The seal plug 290 may be inserted into the coolant passage 200 prior to application of the insulating varnish / resin 240 during the VPI process. FIG. 11 illustrates the coolant passage 200 open. The seal plug 290 may be removed or otherwise removed from the coolant passage 200. Other components and configurations may be used herein.

[0014] 12 and 13 illustrate further examples of coolant passage seals 250 as may be described herein. In this case, an expanded seal plug 320 is shown in FIG. 12. The expanded seal plug 320 may be similar to the seal plug 290 described above, but includes a plug body connector 330 that extends the length of the coolant passage 200. Accordingly, the expanded seal plug 320 may have a plug body 300 with an O-ring 270 and adhesive 280 disposed on either end of the plug body connector 330. The expanded seal plug 320 may be inserted into the coolant passage 200 prior to application of the insulating varnish / resin 240 in a VPI process. FIG. 13 illustrates the coolant passage 200 open. The expanded seal plug 320 may be detached or otherwise removed from the coolant passage 200. Other components and configurations may be used herein.

[0015] 14 and 15 show further examples of coolant passage seals 250 as may be described herein. In this case, a threaded seal plug 350 is shown in FIG. 14. The threaded seal plug 350 has a threaded body 360 sized to mate with the core end ring 220 and may have accommodating threads therein. The threaded seal plug 350 may have an O-ring 270 and adhesive 280 at one end of the threaded body 360 for the coolant passage 200. The threaded seal plug 350 may be inserted into the core end ring 220 of the coolant passage 200 prior to application of the insulating varnish / resin 240 in the VPI process. FIG. 15 shows the coolant passage 200 opened. The threaded seal plug 350 may be detached or otherwise removed from the coolant passage 200. Other components and configurations may be used herein.

[0016] In this manner, the coolant passage seals 250 provide an effective seal for the coolant passages 200 in the stator 130 of the electric machine 100 during the application of the varnish / resin 240 during the VPI process. By sealing these coolant passages 200 during processing, the shape, size, routing, and other types of geometries of the coolant passages 200 can be designed for performance without interfering with manufacturability or resin processing. The use of the coolant passage seals 250 largely eliminates concerns about foreign debris generated throughout the manufacturing process.

[0017] It will be apparent that the foregoing relates only to certain embodiments of this application and the resulting patent. Numerous changes and modifications may be made herein by one skilled in the art without departing from the general spirit and scope of the invention as defined by the following claims and their equivalents.

[0018] Further aspects of the invention are provided by the subject matter of the following clauses. [Embodiment 1] A stator suitable for an application of an insulating varnish or resin in a vacuum pressure impregnation process, the stator including a plurality of conductive windings and a coolant passage extending through the stator, the coolant passage being sealed via a coolant passage seal. [Embodiment 2] 10. The stator of any preceding embodiment, further comprising a plurality of coolant passages, each of the plurality of coolant passages being sealed via the coolant passage seal. [Embodiment 3] 10. The stator of any preceding embodiment, wherein the coolant passage is surrounded by a core end ring. [Embodiment 4] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an extended core end ring. [Embodiment 5] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an O-ring and an adhesive applied to the extended core end ring. [Embodiment 6] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises a sealing plug. [Embodiment 7] 10. The stator of any preceding embodiment, wherein the sealing plug comprises a plug body and an extended flange. [Embodiment 8] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an O-ring and an adhesive applied to the sealing plug. [Embodiment 9] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an extended sealing plug. [Embodiment 10] 10. The stator of any preceding embodiment, wherein the extended sealing plug comprises a pair of sealing plugs connected by a plug body connector. [Embodiment 11] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an O-ring and an adhesive applied to the extended sealing plug. [Embodiment 12] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises a threaded sealing plug. [Embodiment 13] 10. The stator of any preceding embodiment, wherein the threaded sealing plug comprises a threaded body. [Embodiment 14] 10. The stator of any preceding embodiment, wherein the coolant passage seal comprises an O-ring and an adhesive applied to the threaded sealing plug. [Embodiment 15] 1. A method of manufacturing a stator for an electrical machine, the method including the steps of drilling a coolant passage through the stator, sealing the coolant passage with a coolant passage seal, applying an insulating varnish or resin to the stator in a vacuum pressure impregnation process, and removing the coolant passage seal from the coolant passage. [Embodiment 16] An electric machine stator suitable for an application of an insulating varnish or resin in a vacuum pressure impregnation process, the electric machine stator including a rotor, a stator, a plurality of conductive windings in the stator, and a plurality of coolant passages extending through the stator, each of the plurality of coolant passages being sealed via a coolant passage seal. [Embodiment 17] 10. The electric machine of any preceding embodiment, wherein the coolant passage seal comprises an extended core end ring. [Embodiment 18] 10. The electric machine of any preceding embodiment, wherein the coolant passage seal comprises a sealing plug. [Embodiment 19] 10. The electric machine of any preceding embodiment, wherein the coolant passage seal comprises an extended sealing plug. [Embodiment 20] 10. The electric machine of any preceding embodiment, wherein the coolant passage seal comprises a threaded sealing plug. [Explanation of symbols]

[0019] 100: Electric machine 110: Motor 120: Generator 130: Stator 140: Rotor 150: Stator frame 160: Body 170: Conductive windings 180: Shaft 190: Substantially cylindrical body 200: Coolant passages 210: Cooling flow 220: Core end ring 230: Thin laminate stack 240: Insulating varnish / resin 250: Coolant passage seal 260: Expanded core end ring 270: O-ring 280: Adhesive 290: Seal plug 300: Plug body 310: Expanded flange 320: Expanded seal plug 330: Plug body connector 350: Threaded seal plug 360: Threaded body RA: Rotating shaft

Claims

1. 1. A stator suitable for application of insulating varnish or resin in a vacuum pressure impregnation process, the stator including a plurality of conductive windings and a coolant passage extending therethrough, the coolant passage being sealed with a coolant passage seal.

2. The stator of claim 1 further comprising a plurality of coolant passages, each of said plurality of coolant passages being sealed with a coolant passage seal.

3. The stator of claim 1 , wherein the coolant passages are surrounded by core end rings.

4. The stator of claim 1 , wherein the coolant passage seal comprises an expanded core end ring.

5. The stator of claim 4 , wherein the coolant passage seal comprises an O-ring and an adhesive applied to the expanded core end ring.

6. The stator of claim 1 , wherein the coolant passage seal comprises a seal plug.

7. The stator of claim 6 , wherein the seal plug comprises a plug body and an extension flange.

8. The stator of claim 6 , wherein the coolant passage seal comprises an O-ring and an adhesive applied to the seal plug.

9. The stator of claim 1 , wherein the coolant passage seal comprises an expanded seal plug.

10. The stator of claim 9 , wherein the expanded seal plug comprises a pair of seal plugs connected by a plug body connector.

11. The stator of claim 9 , wherein the coolant passage seal comprises an O-ring and an adhesive applied to the expanded seal plug.

12. The stator of claim 1 , wherein the coolant passage seal comprises a threaded seal plug.

13. The stator of claim 12 , wherein the threaded seal plug comprises a threaded body.

14. The stator of claim 12 , wherein the coolant passage seal comprises an O-ring and an adhesive applied to the threaded seal plug.

15. 1. An electrical machine stator suitable for application of insulating varnish or resin in a vacuum pressure impregnation process, comprising: A rotor, a stator; a plurality of conductive windings within the stator; a plurality of coolant passages extending through the stator; Including, an electrical machine stator, wherein each of the plurality of coolant passages is sealed with a coolant passage seal;

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