Vertical motor

Abstract

The utility model relates to the technical field of motors, in particular to a vertical motor, which is characterized in that an upper end cover is designed to be in clearance fit with a stator, and then the upper end cover and the stator are detachably and fixedly connected by using a fixing assembly. The lower end cover is designed to be of an annular structure formed by splicing the left lower end cover and the right lower end cover, and then the left lower end cover and the right lower end cover are locked through the locking assembly so as to achieve connection between the lower end cover and the stator shaft. Therefore, the upper end cover and the lower end cover of the vertical motor are simpler in structure and processing, the requirement on processing precision is reduced, and the vertical motor is more convenient to mount and dismount and low in maintenance cost.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a vertical motor. Background Technology

[0002] Large vertical motors are widely used in air-cooled power plant systems and vertical axis wind turbine generators in my country. However, due to their large size, the end caps on these motors are also quite large. The commonly used method for installing end caps is to use an interference fit or a transition fit between the end cap and the motor shaft. This method requires a high degree of precision in the fit between the end cap and the motor shaft, thus demanding very high machining accuracy from the end cap. Furthermore, this method makes the installation and removal of the end cap extremely difficult.

[0003] Therefore, there is an urgent need for a motor end cover that does not require high processing precision and is easy to disassemble, which will have a broader prospect for promotion and application. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, this utility model provides a vertical motor, which solves the problems of high processing precision requirements for the upper and lower end covers of traditional vertical motors and the difficulty of installation and disassembly.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0008] This utility model provides a vertical motor, including a stator, an upper bearing assembly, an upper end cover, and a fixing assembly. The upper bearing assembly is fitted onto the upper end of the stator, and the upper end cover is located above the upper bearing assembly and fitted onto the top of the stator with a clearance fit. The fixing assembly is used to detachably fix the upper end cover to the stator. The fixing assembly is located on the upper side of the upper end cover and the stator.

[0009] Optionally, multiple sets of fixing components are evenly arranged in the circumferential direction of the stator. Multiple circular grooves are provided corresponding to these multiple sets of fixing components. Each circular groove is formed by combining semi-circular grooves respectively provided on the upper end cover and the upper surface of the stator. Threaded holes are provided at the bottom of each of the two semi-circular grooves.

[0010] The fixing assembly includes a circular plate and a bolt assembly. The circular plate is placed in the circular groove, and the bolt assembly includes bolts that are screwed into threaded holes in two semi-circular grooves respectively.

[0011] Optionally, the upper end cover is an annular structure with an L-shaped cross-section, and the upper end cover is oriented with its L-shaped cross-section in a downward and outward direction relative to the stator;

[0012] A semi-circular groove is provided at the junction of the horizontal and vertical edges of the upper end cap;

[0013] The lower surface of the horizontal edge of the upper end cover is provided with a first annular groove, which can be mutually fitted with the first annular protrusion on the opposite surface of the upper bearing assembly cover to form a labyrinth seal structure.

[0014] The first annular groove and the first annular protrusion are configured in one or multiple sets coaxially;

[0015] The vertical edge of the upper end cover passes through the gap between the upper cover of the upper bearing assembly and the stator, and abuts against the inner ring of the bearing in the upper bearing assembly.

[0016] Optionally, a groove is provided on the surface of the upper end cover that forms a clearance fit with the stator, and a sealing ring is provided in the groove.

[0017] Optionally, multiple lifting lugs are evenly fixed on the upper surface of the upper end cap, and multiple set screw holes are evenly provided.

[0018] Optionally, the vertical motor also includes a lower end cover and a lower bearing assembly. The lower bearing assembly is fitted onto the lower end of the stator. The lower end cover is formed by the left lower end cover and the right lower end cover joining together to form a ring structure. The lower end cover is located below the lower bearing assembly. The left lower end cover and the right lower end cover are detachably connected by a locking assembly. When the left lower end cover and the right lower end cover are in the connected state, the lower end cover holds the stator tightly.

[0019] Optionally, the lower surfaces of the left and right lower end covers adjacent to each other at the connection point are provided with lugs, and the locking assembly includes bolts and nuts, which detachably connect the lugs corresponding to the left and right lower end covers.

[0020] Optionally, the lower end cover has a U-shaped annular structure in cross-section, and the outer annular protrusion of the lower end cover and the second annular groove on the opposite surface of the lower cover of the lower bearing assembly form a labyrinth seal structure through clearance fit.

[0021] Optionally, the surface of the lower end cover that forms a tight fit with the stator is provided with a groove II, and a sealing ring II is provided in the groove II.

[0022] Optionally, the vertical motor is a large vertical motor used in power plant air-cooled systems or vertical axis wind turbine generator sets.

[0023] (III) Beneficial Effects

[0024] The beneficial effects of this utility model are:

[0025] This utility model discloses a vertical motor. By designing the upper end cover to fit the stator with a clearance, and then using a fixing component to detachably fix the upper end cover to the stator, the structure and processing of the upper end cover are simplified, the requirements for processing accuracy are reduced, and the installation and disassembly are more convenient and the maintenance cost is low.

[0026] This utility model discloses a vertical motor in which the lower end cover is designed as a ring structure formed by assembling a lower left end cover and a lower right end cover. The lower left end cover and the lower right end cover are then locked together by a locking assembly to connect the lower end cover to the stator shaft. This makes the structure and processing of the lower end cover simpler, reduces the requirements for processing accuracy, and makes installation and disassembly more convenient and maintenance costs lower. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of Embodiment 1 of a vertical motor according to the present invention;

[0028] Figure 2 for Figure 1 A partial sectional view of the upper end cover area of ​​the vertical motor shown.

[0029] Figure 3 for Figure 1 The diagram shows the installation of the upper cover and stator of a vertical motor.

[0030] Figure 4 for Figure 3 A schematic diagram of the fixing components used for mounting the upper end cover and the stator;

[0031] Figure 5 for Figure 1 A schematic diagram of the upper cover of the vertical motor shown;

[0032] Figure 6 for Figure 5 The cross-sectional view of the upper end cap is shown;

[0033] Figure 7 for Figure 1 A partial sectional view of the lower end cover area of ​​the vertical motor shown.

[0034] Figure 8 for Figure 1 A schematic diagram of the lower end cover of the vertical motor shown.

[0035] Figure 9 for Figure 8 The cross-sectional view of the lower end cap is shown.

[0036] [Explanation of Labels in the Attached Image]

[0037] 1: Stator;

[0038] 2: Upper bearing assembly; 21: Upper cover; 211: First annular protrusion;

[0039] 3: Top cap; 31: Lifting lug; 32: Top screw hole; 33: First annular groove; 34: Groove one; 35: Semi-circular groove; 36: Horizontal edge; 37: Vertical edge;

[0040] 4: Fixing component; 41: Circular plate; 42: Bolt assembly;

[0041] 5: Sealing ring one;

[0042] 6: Lower end cap; 61: Lower left end cap; 62: Lower right end cap; 63: Ear seat; 64: Groove II; 65: Inner ring-shaped protrusion; 66: Ring-shaped base plate; 67: Outer ring-shaped protrusion;

[0043] 7: Lower bearing assembly; 71: Lower cover; 711: Second annular groove;

[0044] 8: Locking assembly;

[0045] 9: Sealing ring two. Detailed Implementation

[0046] To better explain and facilitate understanding of this utility model, a detailed description of its specific embodiments is provided below with reference to the accompanying drawings. In this document, directional terms such as "upper," "lower," "left," and "right" are used interchangeably. Figure 1 The orientation is used as a reference.

[0047] This utility model discloses a vertical motor. The upper end cover is designed to have a clearance fit with the stator, and a fixing assembly is used to detachably fix the upper end cover to the stator. The lower end cover is designed as a ring structure formed by assembling a lower left end cover and a lower right end cover, and a locking assembly is used to lock the lower end cover to connect it to the stator shaft. This simplifies the structure and processing of the upper and lower end covers of the vertical motor, reduces the requirements for processing precision, and makes installation and disassembly more convenient and maintenance costs lower.

[0048] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0049] Example 1:

[0050] Reference Figures 1 to 4This embodiment provides a large vertical motor for use in power plant air-cooled systems or wind turbine generator sets, particularly suitable for air-cooled towers. The vertical motor includes a stator 1, an upper bearing assembly 2, an upper end cover 3, and a fixing assembly 4 (the fixing assembly is as follows...). Figure 4 (As shown). The upper bearing assembly 2 is fitted onto the upper end of the stator 1. The upper end cover 3 is located above the upper bearing assembly 2 and is fitted onto the top of the stator 1 with a clearance fit. The upper end cover 3 and the stator 1 are detachably fixed using a fixing assembly 4. The fixing assembly 4 is located on the upper side of the upper end cover 3 and the stator 1. In this embodiment, three sets of fixing assemblies 4 are evenly arranged in the circumference of the stator 1.

[0051] Simultaneously, three circular grooves are provided corresponding to the three sets of fixing components 4. These circular grooves are formed by the assembly of semi-circular grooves 35 respectively provided on the upper surface of the upper end cover 3 and the stator 1. Each of the two semi-circular grooves 35 has a threaded hole at its bottom. Each set of fixing components 4 includes a circular plate 41 and a bolt group 42. The bolt group 42 includes two bolts, and the circular plate 41 has two holes (through holes or threaded holes). During installation, the circular plate 41 is placed in the circular groove, and the two bolts in the bolt group 42 are screwed through the two holes of the circular plate 41 and engaged with the threaded holes in the two semi-circular grooves 35.

[0052] Of course, this utility model is not limited to this. The method for achieving the detachable fixing of the upper end cover 3 and the stator 1 can be any method that can be conceived by those skilled in the art. For example, the bolt connection can be changed to a pin hole connection, or a pre-fixed connecting plate can be provided at either end of the upper end cover or the stator (e.g., pre-welded). During installation, fasteners can be used to fix the connecting plate to another part without a connecting plate. At the same time, the number of fixing components can also be set in multiple groups according to the size of different motors and the different strength requirements, but at least two groups should be set symmetrically. In addition, the number of bolts in each bolt group 42 is not limited to two. The number of holes on the circular plate 41 is the same as the number of bolts, and the sum of the number of threaded holes in the two semi-circular grooves 35 is the same as the number of bolts.

[0053] In summary, since the upper end cover 3 and the stator 1 adopt a clearance fit, it is no longer necessary to use press-fitting, heat fitting or other methods to install as traditional end covers. Therefore, the requirements for the machining accuracy of the upper end cover 3 can be reduced. When disassembly is required, the upper end cover 3 can be easily removed by simply removing the fixing components between the two.

[0054] In this embodiment, two lifting lugs 31 are evenly fixed to the upper surface of the motor upper cover 3, and two set screw holes 32 are evenly arranged. The number of lifting lugs 31 and set screw holes 32 is not limited by this embodiment and can be adjusted arbitrarily according to actual needs. However, they should be arranged as far apart as possible so that the position of the set screw holes 32 avoids the operating space of the lifting strap when lifting through the lifting lugs 31. Setting up lifting lugs 31 and set screw holes 32 makes the disassembly and assembly of the upper cover 3 more convenient and quick.

[0055] like Figure 5 , Figure 6 As shown in the figure, the upper cover 3 in this embodiment is an L-shaped annular structure. Specifically, the upper cover 3 is formed by connecting a horizontal side 36 and a vertical side 37, with the top of the vertical side 37 connected to the inner ring of the horizontal side 36. The horizontal side 36 of the upper cover 3 refers to the horizontal annular structure portion of the upper cover 3 when viewed from the installed state; the vertical side 37 refers to the vertical annular structure portion of the upper cover 3 when viewed from the installed state. During installation, the upper cover 3 is oriented with its L-shaped cross-section downwards and outwards relative to the stator 1, and the semi-circular groove 35 is located at the connection between the horizontal side 36 and the vertical side 37. Thus, when the connection between the fixing component and the upper cover 3 is at the connection between the horizontal side 36 and the vertical side 37, the connection strength is higher.

[0056] like Figure 2 As shown, the upper bearing assembly 2 includes an upper cover 21 and a bearing. The upper cover 21 is located above the bearing, and its upper surface is opposite to the lower surface of the transverse edge 36 of the upper end cover 3. The upper surface of the upper cover 21 has two coaxially arranged radially aligned first annular protrusions 211, and the lower surface of the transverse edge 36 of the upper end cover 3 has two coaxially arranged radially aligned first annular grooves 33. The two first annular grooves 33 and the two first annular protrusions 211 are fitted together with a clearance to form a labyrinth seal structure. The vertical edge 37 of the upper end cover 3 passes through the gap between the upper cover 21 and the stator 1 of the upper bearing assembly 2, and abuts against the inner ring of the bearing in the upper bearing assembly 2.

[0057] Also see Figure 6 The inner surface of the vertical edge 37 of the upper end cover 3 forms a clearance fit with the outer peripheral wall of the stator 1. A groove 34 is provided on the inner surface of the vertical edge 37 of the upper end cover 3, and a sealing ring 5 is provided in the groove 34.

[0058] In summary, designing the upper cover 3 with a labyrinth seal and installing a sealing ring 5 on the inner side of the upper cover 3 are both to ensure the overall sealing performance of the motor and avoid problems such as oil leakage.

[0059] Of course, this utility model is not limited to the above structure. For example, the first annular groove 33 and the first annular protrusion 211 can be provided in one set or multiple sets coaxially, and are not limited to two sets. The groove 34 and the sealing ring 5 can also be provided in multiple sets with vertical spacing.

[0060] Reference Figure 1 , Figure 7 , Figure 8 As shown, the vertical motor in this embodiment also includes a lower end cover 6 and a lower bearing assembly 7. The lower bearing assembly 7 is fitted onto the lower end of the stator 1. The lower end cover 6 is formed by the left lower end cover 61 and the right lower end cover 62 to form a ring structure. The lower end cover 6 is located below the lower bearing assembly 7. The left lower end cover 61 and the right lower end cover 62 are detachably connected by a locking assembly 8. When the left lower end cover 61 and the right lower end cover 62 are in the connected state, the lower end cover 6 holds the stator 1 tightly. In this embodiment, it is preferable to provide lugs 63 on the lower surfaces of the lower left end cover 61 and the lower right end cover 62 adjacent to each other at their connection point. The locking assembly 8 includes bolts and nuts, which detachably connect the lugs 63 corresponding to the lower left end cover 61 and the lower right end cover 62. Of course, other methods that those skilled in the art can conceive of can also be used to connect the lower left end cover 61 and the lower right end cover 62 (wherein the "left" and "right" in the lower left end cover 61 and the lower right end cover 62 are only used to distinguish the two parts of the lower end cover 6, and do not represent the specific orientation or other issues during installation. At the same time, the lower end cover 6 can also be divided into equal / unequal multi-part forms according to actual needs). Since the lower end cover 6 adopts a split-half structure, dividing the entire lower end cover 6 into two or more forms, it is no longer necessary to use press-fitting, heat-fitting, or other methods for installation like traditional end covers. Therefore, the requirements for the machining accuracy of the lower end cover 6 can also be reduced. When disassembly is required, it is only necessary to remove the connecting parts between the split lower end covers to directly remove the multi-part lower end cover. The operation is simple, convenient, and quick.

[0061] like Figures 7-9As shown, the lower end cover 6 has a U-shaped annular structure in cross-section, comprising an inner annular protrusion 65 and an outer annular protrusion 67 spaced apart, and an annular base plate 66 connecting their bottom ends. The lower bearing assembly 7 includes a lower cover 71 and a bearing. The lower cover 71 is located below the bearing, and its lower surface faces the outer annular protrusion 67 and the inner annular protrusion 65 of the lower end cover 6. The lower surface of the lower cover 71 has a second annular groove 711. The outer annular protrusion 67 of the lower end cover 6 and the second annular groove 711 on the opposite surface of the lower cover 71 of the lower bearing assembly 7 form a labyrinth seal structure through clearance fit. At the same time, the inner surface of the inner annular protrusion 65 of the lower end cover 6 is tightly fitted with the stator 1, and a second groove 64 is provided on this inner surface, within which a second sealing ring 9 is provided. The labyrinth seal structure between the lower end cover 6 and the lower bearing assembly 7, and the sealing ring 9 on the inner surface of the lower end cover 6, are also designed to ensure the overall sealing performance of the motor and prevent problems such as oil leakage.

[0062] The following is a brief description of the installation and removal process of the upper and lower end caps in Embodiment 1:

[0063] 1. Installation and removal of the upper cover 3

[0064] During installation, fix one end of the sling to the overhead crane and the other end to the lifting lug 31 on the upper cover. Smoothly hoist the upper cover 3 to the top of the motor, align it with the stator 1, and slowly lower the upper cover 3 until it is completely fitted onto the stator 1. At this time, the semi-circular groove 35 on the upper cover 3 and the semi-circular groove 35 on the stator 1 are aligned to form a circular groove that can accommodate the circular plate 41. Place the circular plate 41 in this groove, and use the bolts of the bolt group 42 to pass through the holes on the circular plate 41 and screw them into the bolt holes at the bottom of the semi-circular groove 35. Remove the sling to complete the installation.

[0065] During disassembly, fix one end of the sling to the overhead crane and the other end to the lifting lug 31 on the upper end cover. Remove the bolts from the bolt group 42 from the upper end cover 3 and the stator 1. Remove the circular plate 41 and use a tool bolt to simultaneously screw into multiple set screw holes 32. After the tool bolt presses against the upper cover 21 of the upper bearing assembly 2, continue to screw it in slowly. After the upper end cover 3 is lifted and loosened, slowly lift the upper end cover 3 vertically upward to complete the disassembly.

[0066] 2. Installation and removal of the lower end cover 6

[0067] During installation, place the lower left end cover 61 and the lower right end cover 62 onto the corresponding positions on the stator 1. Use the locking assembly 8 to connect and lock the lugs 63 on the lower surface where the lower left end cover 61 and the lower right end cover 62 meet, until the lower end cover 6 and the stator 1 are tightly clamped together, thus completing the installation.

[0068] During disassembly, remove the locking components 8 at each ear seat 63, and then remove the lower left end cover 61 and the lower right end cover 62 directly to complete the disassembly.

[0069] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0070] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0071] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0072] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A vertical motor, comprising a stator (1) and an upper bearing assembly (2), wherein the upper bearing assembly (2) is fitted onto the upper end of the stator (1), characterized in that: It also includes an upper end cap (3) and a fixing component (4); The upper end cover (3) is located above the upper bearing assembly (2) and is fitted onto the top of the stator (1) with a clearance fit. It is detachably fixed to the stator (1) by a fixing assembly (4), which is located on the upper side of the upper end cover (3) and the stator (1).

2. The vertical motor according to claim 1, characterized in that: Multiple sets of fixing components (4) are evenly arranged in the circumferential direction of the stator (1); Multiple circular grooves are provided for the multiple sets of fixing components (4). The circular grooves are formed by combining semi-circular grooves (35) respectively provided on the upper surface of the upper end cover (3) and the stator (1). Threaded holes are provided at the bottom of the two semi-circular grooves (35). The fixing component (4) includes a circular plate (41) and a bolt assembly (42). The circular plate (41) is placed in the circular groove, and the bolt assembly (42) includes bolts that are screwed into threaded holes in the two semi-circular grooves (35).

3. The vertical motor according to claim 2, characterized in that: The upper end cover (3) is an L-shaped annular structure, and the upper end cover (3) is oriented in a downward and outward direction relative to the stator with its L-shaped cross section. The semi-circular groove (35) is provided at the connection between the horizontal edge (36) and the vertical edge (37) of the upper end cover (3); The lower surface of the transverse edge (36) of the upper end cover (3) is provided with a first annular groove (33), and the first annular groove (33) can be mutually gap-fitted with the first annular protrusion (211) on the opposite surface of the upper cover (21) of the upper bearing assembly (2) to form a labyrinth sealing structure. The first annular groove (33) and the first annular protrusion (211) are provided in one or multiple sets coaxially; The vertical edge (37) of the upper end cover (3) passes through the gap between the upper cover (21) of the upper bearing assembly (2) and the stator (1) and abuts against the inner ring of the bearing of the upper bearing assembly (2).

4. The vertical motor according to claim 1, characterized in that: The upper end cover (3) and the stator (1) have a groove (34) on their surfaces that form a clearance fit, and a sealing ring (5) is provided in the groove (34).

5. The vertical motor according to claim 1, characterized in that: Multiple lifting lugs (31) are evenly fixed on the upper surface of the upper end cover (3) and multiple set screw holes (32) are evenly provided.

6. The vertical motor according to claim 1, characterized in that: It also includes a lower end cover (6) and a lower bearing assembly (7), the lower bearing assembly (7) being fitted onto the lower end of the stator (1); The lower end cover (6) is formed by the left lower end cover (61) and the right lower end cover (62) to form a ring structure. The lower end cover (6) is located below the lower bearing assembly (7). The left lower end cover (61) and the right lower end cover (62) are detachably connected by the locking assembly (8). When the left lower end cover (61) and the right lower end cover (62) are connected, the lower end cover (6) hugs the stator (1).

7. The vertical motor according to claim 6, characterized in that: The lower left end cap (61) and the lower right end cap (62) are both provided with ear seats (63) on the lower surface of the connection between them; The locking assembly (8) includes bolts and nuts, which detachably connect the lower left end cap (61) and the lower right end cap (62) to their corresponding lugs.

8. The vertical motor according to claim 6, characterized in that: The lower end cover (6) has a U-shaped annular structure in cross section. The outer ring protrusion (67) of the lower end cover (6) and the second annular groove (711) on the opposite surface of the lower cover (71) of the lower bearing assembly (7) are mutually gap-fitted to form a labyrinth seal structure.

9. The vertical motor according to claim 6, characterized in that: The lower end cover (6) and the stator (1) have a groove (64) on their surfaces that form a tight fit, and a sealing ring (9) is provided in the groove (64).

10. The vertical motor according to any one of claims 1-9, characterized in that: The vertical motor is a large vertical motor used in power plant air-cooling systems or vertical axis wind turbine generator sets.

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