Resin injection apparatus and method of use

Abstract

A method of injecting resin to secure a rod into a slot of a generator and an apparatus for performing the injection are provided. According to the method, a tube is inserted between the rod and the slot. The steps of injecting the resin having a certain viscosity between the rod and the groove via the tube and retracting the tube by a predetermined distance are repeated until the tube has retracted away from the generator or until the tube has retracted by a predetermined amount.

Description

Background Art

[0001] Generators and in particular three-phase synchronous generators are commonly used in power generation activities to generate grid-applicable electricity using prime movers such as gas turbines, steam turbines, wind turbines, water turbines, etc. A generator typically includes a stator that remains stationary during operation and a rotor that rotates relative to the stator. The rotor typically includes two or more magnetic poles that interact with the stator when rotated to generate a desired current at a desired frequency and voltage. Summary of the Invention

[0002] The stator bars can become loose over time, especially in generators operating with frequent load changes or exposed to transient events. When the bars become loose, gaps may form between the bars and the slots in the core, which can affect the mechanical and / or electrical characteristics of the generator; thereby reducing the life of the generator.

[0003] Vacuum pressure impregnation (VPI) is a known process that uses vacuum and pressure to seal materials with resin. Single vacuum pressure impregnation (SVPI) has relatively easy bar replacement and various ways to add insulation or tight wedges to hold the bars in the slots. Global vacuum pressure impregnation (GVPI) has bars that are glued to the slots during impregnation. Currently, expensive and time-consuming rewinding is required to fix the bars.

[0004] It is desirable to avoid full rewinding of GVPI stator windings for loose windings and fix the bars in the slots without removing the stator or rotor.

[0005] According to one embodiment, an injection device for injecting a fluid between the bars and slots of a generator is provided. The injection device includes a fluid chamber, a tube, and a force member. The tube is disposed at an end of the fluid chamber and includes radial holes. The force member is in communication with the resin chamber to force fluid from the chamber into the tube and out of the radial holes. The tube has a length of at least 100 mm.

[0006] The injection device is used to inject a fluid, such as resin, alcohol or air, between a slot and a rod to fix the rod in the slot. The small size of the insertion position where the tube is inserted between the rod and the slot and the distance at which the tube is inserted between the slot and the rod are particularly challenging. To fit the tube in the insertion position, the outer diameter of the tube needs to be small enough to insert the tube into the insertion position. The size of the outer diameter affects the size of the inner diameter of the tube. A smaller inner diameter creates more resistance and reduces the flow rate compared to a larger inner diameter, which poses a challenge for injecting viscous fluids. Additionally, the wall thickness, which is the distance between the inner diameter and the outer diameter, should be considered. A thin tube wall may be fragile or not have sufficient stiffness for inserting the tube. A thick tube wall may 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 and 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 and a wall thickness of 0.4 mm or greater. In a specific embodiment, the outer diameter of the tube is 3 mm and / or the inner diameter is 2 mm.

[0007] The number of holes in the tube can vary based on the viscosity of the fluid or the type of fluid to be inserted. For example, a single hole can be used for fluids with lower viscosity, while multiple holes can be used for fluids with higher viscosity. For example, a single hole can be used for resins with a viscosity greater than 0 centipoise (cP) and less than 1200 cP, and multiple holes can be used for resins with a viscosity higher than 1200 cP, such as resins in the range of 2000 to 10000 cP. The variation in the number of holes allows for the adjustment of the fluid outlet pressure and velocity to facilitate obtaining a desired result, such as covering with resin or cleaning with alcohol.

[0008] The arrangement of the holes in the tube can vary based on the fluid type or fluid viscosity. For example, if resin is to be guided between the rod and the slot, for a tube with multiple holes, each of the holes can face the same direction, e.g., arranged linearly along the tube, to control the direction of the resin. Before inserting the resin, other fluids, such as a cleaning fluid like alcohol, can be injected between the rod and the slot to remove debris between the rod and the slot. For the cleaning fluid, it may be desirable to radially stagger the holes. The staggered arrangement allows the fluid to contact more locations compared to the linear arrangement. Air can be used as a fluid for drying.

[0009] To facilitate inserting the tube between the rod and the slot, the tube can be tapered at the insertion end of the tube. The insertion end can be blocked to prevent the fluid from being released at the insertion end and forcing the fluid to be released from the radial holes.

[0010] When the size of the tube is smaller than the outflow channel in the fluid chamber, an adapter can be provided between the fluid chamber and the tube. The adapter is attached to the outlet channel in the fluid chamber at one end, and the tube can be inserted into the end of the adapter, applying a compression fitting to fix the tube.

[0011] During or after injection, the tube is retracted a predetermined distance. It may be desirable to mark the tube to indicate the predetermined distance. The predetermined distance may represent the position of the radial cooling holes. The radial cooling holes in the stator are separated by a distance that depends on the stator and may be in the range of 10 mm to 150 mm. By retracting the predetermined distance, fluid filling of the radial cooling holes can be avoided.

[0012] The tube can be inserted at any position between the slot wall and the rod that is large enough to accommodate the tube. It should be understood that the gap between the corner of the slot wall and the rod generally has more space than the gap between the slot wall and the rod. Thus, the insertion position is typically the corner.

[0013] In the description of the following examples and their variants, the nature, features, and advantages of the above-described invention and the manner of achieving them will be explained in more detail in conjunction with the accompanying drawings. The examples and the corresponding variants are used to explain the invention and are not intended to limit the invention to the combinations of features indicated therein, even with respect to combinations of functional features. Furthermore, any feature disclosed in the following examples can be considered to be independent and can be appropriately combined with the features of any of the above embodiments and other aspects thereof. Description of the Drawings

[0014] To easily identify the discussion of any particular element or action, the highest digit(s) in the reference numeral refer to the figure number in which the element is first introduced.

[0015] Figure 1 is a cross-sectional view of a generator taken along the centerline, rotational, or longitudinal axis of the generator.

[0016] Figure 2 is applicable to Figure 1 of the generator.

[0017] Figure 3 is applicable to Figure 1 of the generator.

[0018] Figure 4 is a schematic diagram showing a cross-sectional part of the stator slot.

[0019] Figure 5 is a schematic diagram showing a cross-sectional part of the stator slot.

[0020] Figure 6 is a schematic diagram showing a cross-sectional part of the stator slot to show the gap and the insertion position.

[0021] Figure 7 illustrates aspects of the subject matter according to one embodiment.

[0022] Figure 8Illustrates an embodiment of a tube for an insertion device.

[0023] Figure 9 Illustrates an embodiment of a tube for an insertion device.

[0024] Figure 10 Illustrates another embodiment of a tube for an insertion device.

[0025] Figure 11 Illustrates another embodiment of a tube for an insertion device.

[0026] Figure 12 Illustrates another embodiment of a tube for an insertion device.

[0027] Figure 13 Illustrates method 1300 according to one embodiment. Detailed Description

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

[0029] Various techniques related to systems and methods will now be described with reference to the drawings, where like reference numerals always represent like elements. The following discussion of the drawings and the various embodiments used in this patent document to describe the principles of the present disclosure are for illustration only and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged device. It should be understood that functions described as being performed by certain system elements can be performed by multiple elements. Similarly, for example, an element can be configured to perform functions described as being performed by multiple elements. Multiple innovative teachings of the present application will be described with reference to exemplary non - restrictive embodiments.

[0030] In addition, it should be understood that, unless explicitly restricted in some examples, the words or phrases used herein should be interpreted broadly. For example, the terms "comprising," "having," and "including" and their derivatives mean including without limitation. The singular forms "a," "an," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. In addition, as used herein, the term "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" is inclusive and means "and / or" unless the context clearly indicates otherwise. The phrases "associated therewith" and "related thereto" and their derivatives can mean including, being included therein, being interconnected therewith, containing, being contained therein, being connected to or coupled with it, being able to communicate with it, cooperating with it, interleaving, juxtaposing, being close to, being bound to or coupled with it, having, having its attributes, etc. In addition, although multiple embodiments or configurations may be described herein, without a specific statement to the contrary, any feature, method, step, component, etc. described with respect to one embodiment also applies to other embodiments.

[0031] In addition, although the terms "first," "second," "third," etc. may be used herein to refer to various elements, information, functions, or actions, these elements, information, functions, or actions should not be limited by these terms. Instead, these numerical adjectives are used to distinguish different elements, information, functions, or actions from each other. For example, without departing from the scope of the present disclosure, a first element, information, function, or action may be referred to as a second element, information, function, or action, and similarly, a second element, information, function, or action may be referred to as a first element, information, function, or action.

[0032] In addition, the term "proximate" can mean that an element is relatively close to but does not contact another element, or it can mean that an element contacts another part, unless the context clearly indicates otherwise. In addition, unless explicitly stated otherwise, the phrase "based on" is intended to mean "at least partially based on." The term "about" or "substantially" or similar terms are intended to cover variations in values within the normal industrial manufacturing tolerances for that dimension. If no industrial standard is available, a twenty percent variation will fall within the meaning of these terms unless otherwise stated.

[0033] As Figure 1As shown, generator 100 includes a stator 300 and a rotor 200 that is supported for rotation within the stator 300. The stator 300 includes a stator housing 102 that surrounds and substantially encloses a stator core 104. Generally, the stator core 104 is composed of a plurality of laminations 106 stacked in a longitudinal direction (along the axis of rotation). Each lamination 106 includes cutouts or is otherwise shaped to define desired features of the rotor core, including holes 108, the size of which is set to receive the rotor 200.

[0034] In some configurations, 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 configurations, a cooling gas is used as the 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 bearings 118 positioned at each end of the rotor 200. A turbine coupler 120 is positioned at one end of the rotor 200 to facilitate connecting the rotor 200 to a turbine (e.g., a gas turbine, a steam turbine, a water turbine, a wind turbine, etc.) or to another prime mover. The opposite end of the rotor 200 may include an exciter coupler 122 that allows connection to an exciter or other rotating facility.

[0036] Figure 1 The generator 100 shown is a synchronous generator 100. However, an asynchronous generator or motor may include the features described herein.

[0037] Figure 2 Shown in more detail Figure 1 is the rotor 200. 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 magnetic poles. In the illustrated configuration, two magnetic poles are formed by the rotor windings 204. However, other configurations may include four magnetic poles, eight magnetic poles, or more magnetic poles if desired. The rotor 200 (sometimes referred to as the field) may also include a commutator 206 that provides a connection to an exciter that supplies current to the stator windings at a desired voltage 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 configurations, the rotor 200 is air cooled along with other configurations that utilize another fluid such as hydrogen.

[0039] Turning to Figure 3, more particularly illustrates the stator core 104. In most configurations, the stator core 104 is formed by a series of laminations 106 stacked in a longitudinal direction. Each of the laminations 106 includes a plurality of teeth 302 that are evenly spaced circumferentially around the stator core 104 to define a series of slots extending along the length of the stator core 104. Bars 304 are positioned within the slots and are electrically connected to each other to define a series of windings 306. In the illustrated generator 100, the windings 306 are arranged to define three phases. Typically, the three phases are electrically arranged to define a Δ circuit or a Y circuit as desired. Of course, other configurations may 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 channels 308 that allow coolant to flow along the length of the bar 304.

[0041] In operation, an exciter or other system supplies current to the rotor 200 at a desired voltage. The current flows through the rotor windings 204 to establish two magnetic poles in a two-pole generator and more magnetic poles in a higher-pole generator. A 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 rotates at 3600 RPM to generate 60 Hz of electricity. For 50 Hz of electricity, the rotor 200 rotates at 3000 RPM.

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

[0043] Figure 4 A schematic cross-section of a portion 400 of a stator slot of a GVPI type stator is illustrated. The stator slot portion 400 includes a slot wall 406 that forms a channel for receiving the bar 304. The stator slot portion 400 also includes a block 402 that is a wedge or a spacer. The spacer is disposed between adjacent bars 304, while the wedge is disposed on the radially outermost bar 304. A filler 404, such as resin, is disposed between each slot wall 406 and the bar 304 and between the bar 304 and the block 402. It should be understood that the resin 404 covers more or all of the space between the bar 304 and the slot wall 406 or the block 402, and this illustration is only for clearly showing where the filler 404 is formed rather than showing the length or amount of the resin.

[0044] If the filler 404 has deteriorated or otherwise does not exist between the bar 304 and the slot wall 406 or the block 402, the bar 304 may become loose in the slot.Figure 5 A schematic view of a cross-section of the stator slot portion 500 is illustrated in an exaggerated situation, where there is no filler 404 between the rod 304 and the slot wall 406 or the block 402.

[0045] Figure 6 A schematic view of a cross-section of the stator slot portion 500 with an insertion position 602 for a tube is illustrated. A gap appears where there is no filler and can exist in the corner where the rod is rounded, the corner gap 606, or between the side of the slot wall and the rod, the wall gap 604. The illustrated insertion position 602 is located in the corner gap 606. The corner gap 606 is approximately 3 mm between the corner of the rod 304 and the adjacent slot wall 406 or between the rod 304 and the block 402. This is a larger gap than the wall gap 604. It should be understood that the insertion position can occur at any gap large enough to accommodate the tube.

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

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

[0048] The tube 700 is arranged at the end of the fluid chamber 802. The tube 700 includes an angled end 706 to make insertion in the insertion position 602 easier. A plug is arranged in the end region to prevent fluid from being released at the end and to force the fluid to flow out of at least one radial hole on the tube 700. The tube includes a mark 808 at a predetermined distance to visually indicate where to stop injection to avoid filling the radial cooling holes.

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

[0050] The force member communicates with the resin chamber to force fluid from the chamber into the tube and then out of the radial holes.

[0051] Figure 9Schematic diagram of a tube 900 compatible with an insertion tool and used for injecting a low-viscosity resin having a viscosity greater than 0 cP and less than 1200 cP. The tube 900 includes a single radial hole 902 to direct the resin flow.

[0052] Figure 10 Schematic diagram of a tube 1000 compatible with an insertion tool and used for injecting a higher-viscosity resin having a viscosity greater than 1200 cP. The tube 1000 includes a plurality of radial holes 1002 that face the same radial direction to direct the resin flow in the same direction from each radial hole 1002.

[0053] Figure 11 Schematic diagram of a tube 1100 compatible with an insertion tool and used for injecting a cleaning fluid. The tube 1100 includes a plurality of radially staggered force members 804. The staggered holes face different radial directions, which allows the fluid to flow in multiple directions. More specifically, the radial holes 1102 are perpendicular to each other.

[0054] Figure 12 Schematic diagram of a tube 1200 compatible with an insertion tool and used for injecting air. The tube 1200 includes a plurality of radial holes 1202 that are radially staggered in a helical configuration, thereby allowing the fluid to flow in multiple directions.

[0055] A method of using an injection tool is illustrated in Figure 13 In block 1302, method 1300 inserts the tube into the gap between the rod and the groove. In block 1304, method 1300 injects a resin having a first viscosity via the tube into the gap between the rod and the groove. In block 1306, method 1300 retracts the first tube a predetermined distance. In block 1308, method 1300 repeats the injection of the first resin and the retraction of the first tube therein until the tube has retracted away from the generator or until the tube has retracted a predetermined amount. In block 1310, method 1300 arranges the opening of the radial hole to face the direction of the injected resin during insertion.

[0056] Inserting the tube into the small insertion gap therebetween and guiding the tube along the groove is particularly challenging. That is, a certain flexibility is required to insert the tube, but a certain rigidity is required to make the tube travel along the groove. The end of the tube is designed to allow it to be inserted while also guiding the resin to its intended location with minimal flow loss. The design of the tube maintains rigidity, thereby allowing control of the position and precise metering of the resin flow by removing the tube at a predetermined rate during resin injection.

[0057] Various embodiments have been described that describe specific fluids. It should be understood that other fluids may be used. In addition, various embodiments of tubes for different fluid uses have been shown, such as resins of different viscosities, cleaning fluids, and air. Those skilled in the art will recognize that these are merely examples, and the location of the holes may be different from those shown in the figures, and the number of holes may vary. For example, a lower viscosity resin may be used with multiple radial holes, while a higher viscosity resin may be used with a single radial hole. Additionally, the staggering of the holes may be at a different radial position than the radial positions described. The staggering of the holes may be used with any resin.

[0058] The device and method allow the rod to be reattached to the slot while the stator and rotor are in place.

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

[0060] The description in this application should not be construed as implying that any particular element, step, action, or function is an essential element that must be included within the scope of the claims: the scope of the patent subject matter is defined only by the allowed claims. Additionally, none of these claims is intended to invoke the "means-plus-function" claim configuration unless the exact words "means for" are followed by a participle.

Claims

1. An injection device for fixing a rod into a slot of a generator, comprising: Fluid chamber; a tube disposed at an end of the fluid chamber, the tube comprising radial holes; as well as a force member in communication with the resin chamber to force fluid from the chamber into the tube and out of the radial bore; Wherein, the tube has a length of at least 100 mm.

2. The injection device according to claim 1, in, 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 device according to claim 1 or 2, in, The outer diameter of the tube is 3 mm.

4. The injection device according to any one of claims 1 to 3, in, The inner diameter is 2 mm.

5. The injection device according to any one of claims 1 to 4, in, Only a single radial hole is provided in the tube.

6. The method according to any one of claims 1 to 4, in, The tube includes a plurality of radial holes.

7. The injection device according to claim 6, in, At least a portion of the plurality of holes are linearly aligned in the tube.

8. The injection device according to claim 6, in, At least a portion of the plurality of apertures are radially staggered.

9. The injection device according to any one of claims 1 to 8, in, The ends of the tubes are plugged.

10. The injection device according to any one of claims 1 to 9, comprising: an adapter connecting a tube to the fluid chamber, Therein, the tube is inserted into the adapter and clamped to secure the tube in the adapter.

11. An injection device as claimed in any one of claims 1 to 10, comprising: A marking indicates a predetermined distance, the predetermined distance representing a radial cooling hole in the stator.

12. A method of using an injection device according to any one of claims 1 to 11, comprising: inserting the tube into the gap between the rod and the slot; injecting a resin having a first viscosity between the rod and the groove via the tube; as well as retracting the first tube to a predetermined distance; wherein the injecting of the first resin and the retracting of the first tube are repeated until the tube has been retracted away from the generator or until the tube has been retracted a predetermined amount; and Therein, the opening of the radial hole is arranged to face the direction of the injected resin during the inserting.

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