EP4566155A1

EP4566155A1 - Resin injection apparatus and method of use

Info

Publication number: EP4566155A1
Application number: EP24743125.7A
Authority: EP
Inventors: Tristan Mills; Joshua R. Brown; Michael Verbanic; Garrett WELSHOFER; David Holland
Original assignee: Siemens Energy Inc
Current assignee: Siemens Energy Inc
Priority date: 2023-06-23
Filing date: 2024-06-21
Publication date: 2025-06-11
Also published as: WO2024263866A1; WO2024263846A1; EP4714019A1; KR20250078529A; CN120226248A

Abstract

A method to inject resin to secure a bar into a slot of a generator and an apparatus to perform the injection are provided. According to the method, a tube between is inserted between the bar and the slot. The steps of injecting a resin, with a viscosity, between the bar and the slot via the tube, and retracting the tube by a predetermined distance are repeated until the tube has been retracted out of the generator or until the tube has been retracted by a predefined amount.

Description

RESIN INJECTION APPARATUS AND METHOD OF USE

BACKGROUND

[0001] Generators, and in particular three-phase synchronous generators are often used on power generation activities to generate grid-suitable electricity using a prime mover such as a gas turbine, steam turbine, wind turbine, hydro turbine, and the like. The generators generally include a stator that remains stationary during operation and a rotor that rotates with respect to the stator. The rotor often includes two or more poles that when rotated interact with the stator to generate the desired current at the desired frequency and voltage.

BRIEF SUMMARY

[0002] Stator bars can become loose over time especially in generators that are operated with frequent load changes or are exposed to transient events. When the bars become loose, a gap may be formed between the bars and the slot in the core which may affect the mechanical and/or electrical properties of the generator; thereby, reducing the life of the generator.

[0003] Vacuum Pressure Impregnation (VPI) is a known process that uses a vacuum and pressure to seal materials with resin. Single Vacuum Pressure Impregnation (SVPI) have relatively easy bar replacement and various ways to add insulation or tight wedges to secure the bars in the slot. Global Vacuum Pressure Impregnation (GVPI) have the bars glued to the slot during impregnation. Currently a rewind, which is expensive and time consuming, would be needed to secure the bars.

[0004] It is desirable to avoid a complete rewind of a GVPI stator winding for loose windings and to secure the bar in the slot without removal of the stator or the rotor.

[0005] According to an embodiment, an injection apparatus for injecting fluids between a bar and a slot of a generator is provided. The injection apparatus includes a fluid chamber, a tube, and a force member. The tube is arranged at an end of the fluid chamber and comprises a radial aperture. The force member is in communication with the resin chamber to force fluid from the chamber into the tube and out of the radial aperture. The tube has aa length of at least 100 mm long.

[0006] The injection apparatus is used to inject a fluid, such as a resin, alcohol, or air, between the slot and the bar to secure the bar in the slot. The small dimension of the insertion location into which the tube is inserted between the bar and the slot as well as the distance at which the tube is inserted between the slot and the bar is particularly challenging. In order to for the tube to fit in the insertion location, the outer diameter of the tube needs to be small enough for inserting the tube into the insertion location. The size of the outer diameter influences the size of the inner diameter of the tube. A smaller inner diameter creates more resistance than a larger inner diameter and reduces the flow rate that creates challenges for injecting a viscous fluid. Additionally, a wall thickness, which is the distance between the inner diameter and the outer diameter, should be considered. A thin tube wall can be brittle or not have a sufficient rigidity in order to insert the tube. A thick tube wall can reduce the flow rate to an insufficient amount. In an embodiment, the tube has an outer diameter between 2.5 mm and 3.2 mm with a wall thickness of 0.4 mm or greater. In another embodiment, the tube has an outer diameter between 2.5 mm and 3 mm with a wall thickness of 0.4 mm or greater. In a particular embodiment, the outer diameter of the tube is 3 mm and/or the inner diameter is 2 mm.

[0007] The number of apertures in the tube may vary based on the viscosity of fluid or the type of fluid to be inserted. By way of example, a single aperture may be used for fluids with lower viscosity whereas multiple apertures may be used for fluids with higher viscosity. For example, a single aperture could be used for a resin with a viscosity greater than 0 centipoise (cP) and less than 1200 cP and multiple apertures could be used for a resin with a higher viscosity than 1200 cP, such as a resin with a viscosity in the range of 2000 to 10000 cP. The change in the number of apertures allows for adjustment of the fluid exit pressure and velocity to facilitate a desired outcome such as coverage with a resin or cleaning with alcohol.

[0008] The placement of apertures in the tube may vary based on the fluid type or fluid viscosity. For example, if the resin is to be directed between the bar and slot, for a tube with multiple apertures, each of the apertures may face the same direction, e.g., linearly along tube, to control the direction of the resin. Other fluids may be injected between the bar and the slot, for example a cleaning fluid, such as alcohol, to remove debris between the bar and the slot may be injected prior to the resin insertion. For a cleaning fluid, it may be desirable to stagger the apertures radially. The staggered placement allows the fluid to contact more locations relative to a linear placement. Air may be used as the fluid for drying purposes.

[0009] To facilitate insertion of the tube between the bar and the slot, the tube may be tapered at the insertion end of the tube. The insertion end may be plugged to prevent fluids from being released at the insertion end and to force the fluids to be released from the radial apertures. [0010] An adapter may be provided between the fluid chamber and the tube when the sizes of the tube are smaller than an egress passage in the fluid chamber. The adapter is attached at one end to the egress passage in the fluid chamber and the tube may be inserted into the end of the adapter, a compression fitting is applied to secure the tube.

[0011] During an injection or after the injection, the tube is retracted by a predetermined distance. It may be desirable to mark the tube to indicate the predetermined distance. The predetermined distance may represent the location of a radial cooling apertures. Radial cooling apertures in the stator are separated by a distance, which is stator dependent, and may be in the range of 10 mm to 150 mm. By retracting by the predetermined distance, it may be possible to avoid filing the radial cooling apertures with fluid.

[0012] The tube may be inserted at any location between the slot wall and the bar that is large enough to accommodate the tube. It would be understood that a gap between the corner of the slot wall and the bar generally has more space than a gap between the slot wall and the bar. As such, the insertion location would typically be the corner.

[0013] The properties, features and advantages of the invention described above, as well as the manner in which they are achieved, will be explained in more detail in connection with the figures in the following description of the example and variations thereof. The example and the corresponding variations serve to explain the invention and do not limit the invention to the combinations of features indicated therein, even with respect to functional features. Moreover, any of the features disclosed in the example below may be considered in isolation and suitably combined with the features of any of the above embodiments and their further aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0015] FIG. l is a cross-sectional view of a generator taken along the generator centerline, rotational, or longitudinal axis.

[0016] FIG. 2 is a perspective view of a rotor suitable for use in the generator of FIG. 1.

[0017] FIG. 3 is a perspective view of a portion of a stator suitable for use in the generator of FIG. 1.

[0018] FIG. 4 illustrates a schematic view of a cross section portion of a stator slot. [0019] FIG. 5 illustrates a schematic view of a cross section portion of a stator slot.

[0020] FIG. 6 illustrates a schematic view of a cross section portion of a stator slot to show gaps and insertion locations.

[0021] FIG. 7 illustrates an aspect of the subject matter in accordance with one embodiment.

[0022] FIG. 8 illustrates an embodiment of a tube used in the insertion apparatus.

[0023] FIG. 9 illustrates an embodiment of a tube used in the insertion apparatus.

[0024] FIG. 10 illustrates another embodiment of a tube used in the insertion apparatus.

[0025] FIG. 11 illustrates another embodiment of a tube used in the insertion apparatus.

[0026] FIG. 12 illustrates another embodiment of a tube used in the insertion apparatus.

[0027] FIG. 13 illustrates a method 1300 in accordance with one embodiment.

DETAILED DESCRIPTION

[0028] Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0029] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0030] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0031] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0032] In addition, the term "adjacent to" may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0033] As illustrated in FIG. 1, a generator 100 includes a stator 300 and a rotor 200 supported for rotation within the stator 300. The stator 300 includes a stator housing 102 that surrounds and substantially encloses a stator core 104. Typically, the stator core 104 is made- up of a number of laminations 106 stacked in a longitudinal direction (along a rotational axis). Each lamination 106 includes cut outs or is otherwise shaped to define the desired features of the rotor core, including a bore 108 that is sized to receive the rotor 200.

[0034] In some constructions, a stator cooling system 110 is provided to cool the stator 300 and improve the efficiency and power density of the stator 300. In some constructions, a cooling gas is employed as a stator coolant. However, larger stators 300 may include liquid cooling such as water cooling.

[0035] The rotor 200 includes a rotor shaft 112, a rotor shaft extension 114, and two retaining rings 116 coupled to the rotor shaft extension 114. The illustrated rotor shaft extension 114 is supported for rotation by a bearing 118 positioned at each end of the rotor 200. A turbine coupling 120 is positioned at one end of the rotor 200 to facilitate connection of the rotor 200 to a turbine (e.g., combustion turbine, steam turbine, hydro turbine, wind turbine, etc.) or to another prime mover. The opposite end of the rotor 200 may include an exciter coupling 122 that allows for connection to an exciter or other rotating equipment.

[0036] The generator 100 illustrated in FIG. 1 is a synchronous generator 100. However, asynchronous generators or motors could include the features described herein.

[0037] FIG. 2 illustrates the rotor 200 of FIG. 1 in greater detail. The rotor shaft 112 includes a series of rotor slots 202 that extend longitudinally along the rotor shaft 112. Rotor windings 204 are positioned within the rotor slots 202 to define one or more pairs of poles. In the illustrated construction two poles are formed by the rotor windings 204. However, other constructions could include four poles, eight poles or more poles if desired. The rotor 200, sometimes referred to as a field, may also include a commutator 206 that provides a connection to an exciter that provides electrical current at a desired voltage to the stator windings to generate a magnetic field.

[0038] The rotor 200 may also include a rotor cooling system 208 that operates to cool the rotor 200. In some constructions, the rotor 200 is air-cooled with other constructions employing another fluid such as hydrogen.

[0039] Turning to FIG. 3, the stator core 104 is illustrated in greater detail. The stator core 104, in most constructions, is formed from a series of laminations 106 that are stacked in the longitudinal direction. Each of the laminations 106 includes a number of teeth 302 that are evenly spaced circumferentially around the stator core 104 to define a series of slots that extend the length of the stator core 104. Bars 304 are positioned within the slots and are electrically connected to one another to define a series of windings 306. In the illustrated generator 100, the windings 306 are arranged to define three phases. Generally, the three phases are electrically arranged to define a delta-circuit or a Y-circuit as may be desired. Of course, other constructions could include a single phase if desired.

[0040] As part of the stator cooling system 110, each of the bars 304 may include one or more coolant passages 308 that allow for the flow of coolant along the length of the bar 304.

[0041] In operation, an exciter or other system provides current at a desired voltage to the rotor 200. The current flows through the rotor windings 204 to establish two magnetic poles in a two-pole generator and more poles in higher pole generators. The turbine, or other prime mover is coupled to the rotor 200 and operates to rotate the rotor 200 at a desired speed. For a synchronous generator with a two-pole rotor 200, the rotor is rotated at 3600 RPM to generate 60 Hz electricity. For electricity at 50 Hz, the rotor 200 is rotated at 3000 RPM.

[0042] The rotating magnetic field of the rotor 200 interacts with the windings 306 of the generator to induce an alternating three phase current at a frequency that is proportional to the speed of the rotor 200. Each of the rotor 200 and the stator 300 are cooled to increase the current density of the rotor 200 and the stator 300 while also maintaining a desired efficiency and maintenance interval.

[0043] FIG. 4 illustrates a schematic of a cross section of a portion of a stator slot 400 for a GVPI type stator. The stator slot portion 400 includes slot walls 406 that form a channel that houses a bar 304. The stator slot portion 400 further includes a block 402, which is a wedge or a spacer. A spacer is provided between adjacent bars 304 whereas a wedge is arranged on the most radially outward bar 304. A filler 404, e g., resin, is arranged between each slot wall 406 and the bar 304 and between the bar 304 and the block 402. It would be understood that the resin 404 covers more or all the space between the bar 304 and the slot wall 406 or block 402 and that the illustration is merely for clarity to show where the filler 404 is formed and not the length or amount of resin.

[0044] If the filler 404 has deteriorated or otherwise does not exist between the bar 304 and the slot walls 406 or the block 402, the bar 304 may become loose in the slot. FIG. 5 illustrates a schematic of a cross section of a stator slot portion 500 in an exaggerated situation where no filler 404 exists between the bar 304 and the slot walls slot wall 406 or the block 402.

[0045] FIG. 6 illustrates a schematic of a cross section of the stator slot portion 500 with insertion location 602 for a tube. Gaps occur where there is no filler and may be present in the corner where the bars are rounded, corner gap 606, or be present between the slot wall sides and the bar, wall gap 604. The illustrated insertion locations 602 are located in the corner gaps 606. The corner gap 606 is approximately 3 mm, between the bar 304 and the corner of adjoining slot walls 406 or the bar 304 and the block 402. This is a larger clearance than the wall gap 604. It would be understood that an insertion location may occur at any gap large enough to accommodate the tube.

[0046] FIG. 7 is a schematic view of a tube 700 compatible with the insertion tool. The tube has an outer diameter 702, an inner diameter 704, and a length 710. A wall thickness 712 is defined as the distance between the outer diameter 702 and the inner diameter 704. One end of the tube 700 illustrates an angled tip 706 to facilitate insertion. A plug is at the tip end to keep a fluid from being injected from the tip 706 of the tube is at one end of the tube 700 and to force the fluid to be injected from a radial aperture. Radial apertures are illustrated in FIG. 9 - FIG. 12

[0047] FIG. 8 is a schematic view of a resin injection tool 800 includes a fluid chamber 802, a tube 700, adapter 806, clamp 810, and a force member 804.

[0048] The tube 700 is arranged at an end of the fluid chamber 802. The tube 700 includes an angled tip 706 to make insertion in the insertion location 602 easier. A plug is arranged in the tip area to prevent fluid from being released at the tip and to force the fluid from at least one radial aperture on the tube 700. The tube includes markings 808 at predetermined distances to visually indicate where to stop the injection to avoid filing a radial cooling aperture.

[0049] The adapter 806 secures the tube 700 to the fluid chamber 802. The end of the tube 700 opposite of the tip 706 is inserted into the adapter 806 and secured via clamp 810.

[0050] The force member is in communication with the resin chamber to force fluid from the chamber into the tube and subsequently out of the radial aperture.

[0051] FIG. 9 is a schematic view of a tube 900 compatible with the insertion tool and to inject a lower viscosity resin that has a viscosity greater than 0 cP and less than 1200 cP. The tube 900 includes a single radial aperture 902 to direct the resin flow.

[0052] FIG. 10 is a schematic view of a tube 1000 compatible with the insertion tool and to inject a higher viscosity resin that has a viscosity greater 1200 cP. The tube 1000 includes numerous radial apertures 1002, facing the same radial direction, to direct the resin flow in the same direction from each radial aperture 1002. [0053] FIG. 11 is a schematic view of a tube 1100 compatible with the insertion tool and to inject a cleaning fluid. The tube 1100 includes numerous force members 804, that are staggered radially. The staggered apertures are facing in different radial directions which allows for the fluid to flow in multiple directions. More specifically the radial apertures 1102 are perpendicular from each other.

[0054] FIG. 12 is a schematic view of a tube 1200 compatible with the insertion tool and to inject air. The tube 1200 includes a numerous radial aperture 1202, that are staggered radially in a corkscrew configuration allowing the fluid to flow in multiple directions.

[0055] A method of using the injection tool is illustrated in FIG. 13. In block 1302, method 1300 inserts the tube into a gap between the bar and the slot. In block 1304, method 1300 injects a resin, with first viscosity, between the bar and the slot via the tube. In block 1306, method 1300 retracts the first tube by a predetermined distance. In block 1308, method 1300 wherein the injecting of the first resin and retracting of the first tube are repeated until the tube has been retracted out of generator or until the tube has been retracted by a predefined amount. In block 1310, method 1300 wherein the opening of the radial aperture is arranged during the inserting to face in a direction to the inject the resin.

[0056] It is particularly challenging to insert a tube in the small insertion gap between and to direct the tube along the slot. That is there is a certain flexibility needed to insert the tube but a certain rigidity to snake the tube down the slot. The end of the tube is designed to allow it to be inserted while also directing the resin with minimal flow losses where it is intended to go. The design of the tube maintains rigidity, allowing the position to be controlled and the flow of resin to be precisely metered by removing the tube at a pre-defined rate while injecting the resin.

[0057] Various embodiments describing particular fluids have been described. It would be understood that other fluids may be used. Furthermore, various embodiments of tubes for different fluid uses, e.g., resins of different viscosities, cleaning fluid, and air have been illustrated. One skilled in the art would recognize that these are merely examples and that the position of the apertures may vary from the illustrated figures and that the number of apertures may vary. For example, a lower viscous resin may be used with multiple radial apertures and that a higher viscous resin may be used with a single radial aperture. Additionally, the staggering of the apertures may be in different radial positions than described. The staggering of the apertures may be used with any of the resins. [0058] The apparatus and method allow for the bar to be reattached to the slot while the stator and rotor are in place, in-situ.

[0059] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0060] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

CLAIMS What is claimed is:

1. An injection apparatus to secure a bar into a slot of a generator, comprising: a fluid chamber; a tube arranged at an end of the fluid chamber, the tube comprising a radial aperture; and a force member in communication with the resin chamber to force fluid from the chamber into the tube an out of the radial aperture; wherein the tube has a length of at least 100 mm long.

2. The injection apparatus of claim 1, wherein the tube has an outer diameter between 2.7 mm and 3.2 mm, an inner diameter between 1.8 mm and 2.8 mm,

3. The injection apparatus of claim 1 or 2, wherein the outer diameter of the tube is 3 mm.

4. The injection apparatus of any one of claims 1 to 3, wherein the inner diameter is 2 mm.

5. The injection apparatus of any one of claims 1 to 4, wherein only a single radial aperture is configured in the tube.

6. The method of any one of claims 1 to 4, wherein the tube includes a plurality of radial apertures.

7. The injection apparatus of claim 6, wherein at least a portion of the plurality of apertures are aligned linearly in the tube.

8. The injection apparatus of claim 6, wherein at least a portion of the plurality of apertures are staggered radially.

9. The injection apparatus of any one of claims 1 to 8, wherein the end of the tube is plugged.

10. The injection apparatus of any one of claims 1 to 9, comprising an adapter to connect tube to the fluid chamber, wherein the tube inserted inside the adapter and clamped to secure the tube inside the adapter.

11. The injection apparatus of any one of claims 1 to 10, comprising markings to indicate a predetermined distance that represent a radial cooling apertures in the stator.

12. A method of using the injection apparatus any one of claims 1 to 11, comprising: inserting the tube into a gap between the bar and the slot; injecting a resin, with first viscosity, between the bar and the slot via the tube, and retracting the first tube by a predetermined distance wherein the injecting of the first resin and retracting of the first tube are repeated until the tube has been retracted out of generator or until the tube has been retracted by a predefined amount, and wherein the opening of the radial aperture is arranged during the inserting to face in a direction to the inject the resin.