System and assembly for power transmission and generation in a wind turbine

Various power transmission and generation systems and assemblies are provided for a wind turbine. In one embodiment, a power generation system is provided including a transmission having an input axially aligned with an output, the input configured to receive rotary motion generated by a wind driven rotor head, the input located downwind of the output, an electromagnetic apparatus having an input configured to be coupled to the transmission output, and a bearing configured to radially support both the transmission output and the electromagnetic apparatus input. In this way, a common bearing may support both the transmission and electromagnetic apparatus, allowing for a more compact and efficient design while retaining service and repair capabilities.

FIELD

The present application relates to power systems of wind turbines.

BACKGROUND

Due to the high growth rate of the wind turbine industry, an increasing number of power generation components have been developed by a multitude of companies. Many of these companies independently design and manufacture various components included in the power generation system of the wind turbine, such as gearboxes and generators. In this way, manufactures select a desired gearbox, generator, etc., in designing the overall wind turbine. On the other hand, the overall size of a power generation unit in the wind turbine may lead to increased up-tower mass.

As such, various approaches may be used to integrate one or more components of a wind turbine, such as integrating a gearbox and generator in a common housing to form an integrated power generation system.

However, the inventors herein have recognized several issues with such integration. For example, assembling, testing, servicing and/or repairing a fully integrated power generation system may be extremely difficult, leaving the wind turbine inoperable. Therefore, the lifespan of the wind turbine may be significantly reduced or repair and maintenance costs may be excessive. Furthermore, due to the growth in the wind turbine industry, the global supply chain has delivery pressures, and thus an integrated generator and gearbox having a common housing, or other similar features, may overly restrict the separate manufacturing and supply of the gearbox and generator that would otherwise alleviate delivery pressures.

BRIEF DESCRIPTION OF THE INVENTION

Various power transmission, and generation systems, and assemblies are provided for a wind turbine. In one embodiment, a power generation system is provided including a transmission having an input axially aligned with an output, the input configured to receive rotary motion generated by a wind driven rotor head, the input located downwind of the output, an electromagnetic apparatus having an input configured to be coupled to the transmission output, and a bearing configured to radially support both the transmission output and the electromagnetic apparatus input. In this way, a common bearing may support both the transmission and electromagnetic apparatus, allowing for a more compact and efficient design while retaining service and repair capabilities.

This brief description is provided to introduce a selection of concepts in a simplified form that are further described herein. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. Also, the inventors herein have recognized any identified issues and corresponding solutions.

DETAILED DESCRIPTION

A power generating wind turbine10is shown inFIG. 1. The turbine includes a tower12extending substantially vertically out of a base14. The tower may be constructed from a plurality of stacked components. However, it can be appreciated that alternate configurations of the tower are possible, such as a lattice tower. A nacelle16and nacelle bedplate18are positioned atop the tower. A drive unit (not shown) may be included in the nacelle bedplate, allowing the nacelle to rotate about a horizontal plane. The nacelle may be positioned, by the drive unit, directly into the wind, increasing the power output of the wind turbine. Further in some examples, a drive unit controls the vertical pitch of the blades. The nacelle houses a power generation system having a transmission and an electromagnetic apparatus, shown inFIG. 2discussed in greater detail herein. Further, various power electronics and control electronics may be housed in nacelle16.

A main shaft20extends out of the nacelle. The main shaft may be coupled to a transmission by an input carrier (not shown) sharing a common central axis22with the main shaft. Furthermore, the main shaft20may be coupled to a rotor head24. A plurality of rotor blades26may be radially position around the rotor head24. A wind force (not shown) may act on the rotor blades, rotating the blades and therefore the rotor head about the central axis. Thus, the rotor head is wind driven. The rotor head may be configured to reduce drag on the wind turbine, thereby reducing the axial load (e.g. thrust) on bearings in the wind turbine.

A cut-away view of an example nacelle100, which may be used as the nacelle16, is illustrated inFIG. 2, showing various components enclosed therein. The nacelle100houses a power generation system110, allowing wind force to be converted to electrical energy. The power generation system includes components such as a transmission112and an electromagnetic apparatus (e.g. generator)114. The transmission may be configured to increase the rotation speed of the rotary motion generated by the rotor blades. Further, the electromagnetic apparatus114may be configured to convert mechanical energy into electrical energy. The aforementioned components are discussed in greater detail with regard toFIGS. 3-11.

The Nacelle may further include a base-plate102configured to attach to the power generation system (e.g. the transmission and generator) to the nacelle100by torque couplings104. Thus, the torque couplings may react at least a portion of the torque from the transmission. Specifically, in this example, the base-plate includes two torque couplings laterally positioned in the nacelle. However, it can be appreciated that the size, position, and/or shape of the torque couplings may be modified in alternate embodiments.

The nacelle may include various other components such as a main shaft (not shown), extending out of the rotor head, and/or rotor head housing coupling (not shown), configured to support a portion of the rotor head. It can be appreciated that additional coupling configured to attach various components enclosed by the nacelle, such as the generator, may be utilized.

Additionally, a cooling system (not shown) may be included in the nacelle, directing ambient air, around the power generation system, thereby allowing heat to be transferred from the power generation system to the air, cooling the power generation system. The open loop cooling system may passively direct ambient air around the power generation system (e.g. transmission and/or electromagnetic apparatus) and/or actively direct ambient air around the power generation system by the use of a fan (not shown). Additionally or alternatively, a closed loop air or water-based (or other liquid) cooling system (not shown) may be utilized, the cooling system including a radiator configured to remove heat from the water to ambient air. The cooling system may be positioned above the transmission112and/or the electromagnetic apparatus114.

InFIG. 2, nacelle100is sized similarly to production wind turbine designs. The substantial amount of additional space behind power generation system110illustrates the space-saving nature of the example design configurations described in further detail herein. Specifically, as will be described further herein, an integrated assembly used in the power generation system110shares structural supporting, such as bearing elements, among the transmission112and the electromagnetic apparatus114.

In one embodiment, the additional space in the nacelle may be used to house power electronics (e.g., one or more transformers) for converting low-voltage power output of the generator to high voltage power for long-distance transmission. The power electronics may be electronically coupled to the electromagnetic apparatus. As such, up-tower transformers (not shown) may be used. In this way, rather than experiencing low-voltage losses in transmitting the generator output to voltage converters on the ground or the base14of the turbine, it is possible to transmit high voltage power down the tower12, thereby improving overall wind turbine performance.

In an alternative embodiment, a nacelle design may be used which is substantially smaller in size than that shown inFIG. 2. Here, a smaller volume nacelle may be coupled with the space-saving power generation system110to reduce up-tower mass, thereby enabling overall wind turbine nacelle and tower weight savings, for example.

FIGS. 3-11illustrate various views of an embodiment of a power generation assembly111forming at least a portion of the power generation system110, shown inFIG. 2, as well as individual components included in the power generation assembly. Similar parts are labeled accordingly. It can be appreciated that various components in the power generation assembly may be separately manufactured, tested, and then assembled on site, decreasing construction costs. Further, each component may be removed from the nacelle and service (e.g. repaired) or replaced. In this way, it is possible to repair smaller sections of the wind turbine, decreasing the cost of repair.

In particular,FIG. 3illustrates an exploded side view of the power generation assembly.FIG. 4illustrates a cut-away side view of the power generation assembly in an assembled configuration.FIG. 5illustrates another cut-away side view of selected components of the power generation assembly.FIG. 6illustrates an isometric view of the power generation assembly in the assembled configuration.FIG. 7illustrates a front view of the power generation assembly in the assembled configuration.FIG. 8shows a top view of the power generation assembly in the assembled configuration.FIG. 9shows a side view of the power generation assembly in the assembled configuration. Lastly,FIGS. 10-11illustrate isometric views of the transmission and electromagnetic apparatus, respectively, disassembled from one another.

Returning toFIG. 3, it shows transmission112and an electromagnetic apparatus114as components of the power generation assembly111. The transmission may comprise a gearbox as one example for gearing up output of the shaft20, shown inFIG. 1. The transmission112includes an input116, an output118, and a transmission housing117. The transmission housing encloses various components of the transmission, such as a longitudinally positioned planetary gear-train130comprised of various gears as described herein. The transmission is configured to adjust the rotational speed of the input from the wind actuated rotor head, allowing a generator to more efficiently utilize the rotational energy from the transmission to extract electrical power from the power generation system. For instance, the transmission may increase the rotational speed of the input, while reducing torque.

Numerous suitable transmissions having an input and an output may be utilized. In this embodiment, a compound star planetary gearbox including a fixed annulus (e.g. ring gear) is used, due to its compact and efficient design. However, it can be appreciated that alternate suitable types of transmissions may be used, such as a fixed carrier compound star planetary gearbox, simple planetary gearbox, differential planetary gearbox, or power-splitting parallel shaft gearbox with a concentric output shaft, etc. Further, the transmission's input and output may be co-axially aligned, thereby sharing a common central rotating axis119, where the common central axis is the axis of rotation of the input and the output of the transmission. Further, the common central rotating axis119may be located on the centerline of the turbine, turbine rotor, and/or turbine blades.

In the planetary gearbox shown inFIG. 3, the input116of the transmission112includes an input carrier120configured to be rotatably coupled to a rotor head by a suitable coupling, such as a plurality of bolts directed through a plurality bored holes in a flange, by use of a shrink disc, or by an integrated rotor shaft. In this way, the wind driven rotor head may transfer rotational energy into the transmission. Furthermore, the input carrier's axis of rotation may be aligned with the central rotating axis119. The output of the transmission includes a sun gear124rigidly fixed to an output shaft126, such that the output shaft126and the sun gear124rotate as one. Again, the output shaft's rotational axis may be aligned with the central rotating axis119, and the output shaft126may extend outside the transmission housing.

The planetary gear-train130connects the transmission input and output through one or more planet gears orbitally revolving about, and driving, the sun gear (and thus the output shaft). In this example, the gear-train includes a plurality of planet gears (where one planetary gear is formed by interior planet gear section132and exterior planet gear section140with the planetary gears driven by, and rotatably affixed to the input carrier120. Specifically, the input carrier120rotates the central axis of the planetary gears and about the central rotating axis119, where the planets are further driven to rotate about their own axis by the fixed ring gear136.

The input carrier120may be supported by the housing via an input bearing172, such as tapered roller bearing. In other examples, alternate suitable bearings types may be utilized. Further, two bearings,134A and134B may be respectively coupled to the front and the rear portion of the interior planet gear section, allowing the planet gears to rotate about their own axes. It can be appreciated that the number of bearings may be adjusted depending on various design specifications, and further the term bearing may include single, double, triple, or other combination bearings. As noted, a fixed annulus136(e.g. ring gear) may be coupled to the planet gears by meshing engagement with the interior planet gear section, where the fixed annulus is torsionally coupled to and fixed to the transmission housing.

A pair of torque supports138, shown inFIGS. 6-8, are coupled to the transmission housing, react the torque from the annulus, the emergency brake and the generator. As previously discussed with regard toFIG. 2, the torque supports may be fixed to the base-plate included in the nacelle and may vary in design (e.g., a torque ring may be used).

Returning toFIG. 3, and as noted above, the fixed annulus136directs the planet gears in orbital rotation. The exterior planet gear sections are in meshing engagement with the sun gear124, to transfer the motion and rotation of the planet gears into motion of the sun gear and thus the output shaft. Each of the meshing gear engagements, including between the ring gear and the planetary gears, as well as between the planetary gears and the sun gear, may be helical meshing engagement.

The sun gear (and output shaft) may be supported by, and coupled to, transmission bearing174. The transmission bearing174may further be coupled to an exterior portion173of the transmission. The exterior portion may include a downwind portion of the transmission outside of the gear-train. In some examples, the transmission bearing may be a locating bearing including a double row tapered roller bearing including a first and a second row of tapered rollers,175and176, respectively shown also inFIG. 5. Further, in some examples the tapered rollers may be sections of a cone. Each row of tapered roller may include a plurality of rollers each roller having an axis of rotation. Alternatively, the transmission bearing may be a spherical or toroidal roller bearing, also having a first and second row of cylinders. Additionally, the transmission bearing174may include a bearing housing177coupled to a transmission bearing support plate178. Furthermore, the transmission bearing support plate may be coupled (e.g. rigidly attached) to the housing of the transmission. In this way, the bearing may be structurally supported by the transmission housing117.

As will be described further herein, bearing174supports not only the axial gear load generated by the helical gears of the transmission, but also radial loads of the gears, as well as axial and/or radial loads generated by the electromagnetic apparatus114. Specifically, the common bearing174enables and supports rotation of the gearbox gears, as well as the input shaft of the electromagnetic apparatus114, thereby enabling a compact power generation assembly construction. Also, while in this example, the transmission output may be a gear other than the sun gear of a planetary gearbox. For example, various other gears may align to rotate on the same axis as the input of the electromagnetic apparatus114, such as a planet gear and/or ring gear, or others.

The power generation assembly111may further include a drive coupling142, shown also inFIG. 10, coupled to the output shaft and therefore the sun gear. In this embodiment, shoulder bolts144may be used to couple the output shaft to the drive coupling. However, alternate suitable couplings, such as bolts with bushings, may be utilized in other embodiments. Further in some examples, the drive coupling may have the shape of a plate or flange.

Returning toFIG. 3, a braking mechanism146may be rotatably coupled to the drive coupling142. The braking mechanism may be a suitable braking mechanism configured to decrease the speed of the output shaft, such as a disk type braking mechanism, utilizing hydraulically actuated pads. Under some conditions, such as during servicing or repair, motion of the output shaft may be decreased and under some conditions substantially inhibited by the braking mechanism. Further, actuation of the braking mechanism may be responsive to a number of operating conditions including lubrication system degradation. Reducing the speed of the output shaft may include substantially inhibiting motion of the output shaft, and therefore the gear-train. In this way emergency braking of the rotating equipment (e.g. the planetary gear-train) may be provided, if needed.

The electromagnetic apparatus114, which may be a generator or an alternator, is rotatably coupled to the transmission112. The electromagnetic apparatus is configured to transfer rotational energy, received from the transmission, to electrical energy. The electromagnetic apparatus may be coupled to an electrical transmission system (not shown) which may be routed through the tower to the base. In this example, a synchronous type generator is utilized. Alternatively, an asynchronous generator, such as a double fed induction generator, may be utilized. Further, it can be appreciated that other types of suitable hydraulic or hydrostatic couplings, generators or alternators may be used.

As shown inFIG. 3, the electromagnetic apparatus114may include a rotor148electromagnetically interacting with a stator150. The synchronous generator may include a stator frame152at least partially enclosing and structurally supporting the stator. The stator frame may be included in an electromagnetic apparatus housing153, partially surrounding the electromagnetic apparatus. As noted, the transmission housing117is separate from, and may be coupled to and decoupled from, the electromagnetic apparatus housing153. Additionally, the rotor may include a central rotating output shaft154. When the power generation assembly is assembled (as shown inFIG. 4), the central rotating output shaft is axially aligned with the output shaft of the transmission. Returning toFIG. 3, electrical couplings156may be attached to the stator allowing electrical power to be extracted from the electromagnetic apparatus.

The rotor148is supported at exterior ends by bearings, including the transmission bearing174at the front, input, end, and an electromagnetic apparatus bearing186at the rear end. Specifically, electromagnetic apparatus bearing186may be located near an output section188of the electromagnetic apparatus, at an opposite end (e.g. downwind section) of the electromagnetic apparatus as compared to the rotor coupling. In some examples, the electromagnetic apparatus bearing is a non-locating single row cylindrical roller bearing. In other examples, alternate types of suitable types of non-locating bearings may be utilized. The electromagnetic apparatus bearing may receive radial loading from the weight of the rotor and associated components. It can be appreciated that the majority of the loading may be in the radial direction, facilitating the use of the non-tapered cylindrical roller bearing. Note thatFIG. 3shows the rotor supported by one locating (transmission bearing174) and one non-locating bearing (bearing186), where in some examples no additional bearings may be used to support the rotor.

As noted above, because the rotor shares a bearing support with the gearbox, when the electromagnetic apparatus114is decoupled from the transmission114, the rotor is not fully supported in electromagnetic apparatus114. Thus, to avoid damage to the rotor, as well as to aid assembly/disassembly, an electromagnetic apparatus input support member, such as a rotor support157, may be used. The rotor support157may be included in and integrally formed in the electromagnetic apparatus housing, and may be configured to receive loads (e.g. radial loads) from the rotor during or after disassembly, or before assembly; yet, allow the rotor to rotate with some resistance during assembly/disassembly and allow free rotation during normal operation of the power generation system. During assembly, the rotor support supports the rotor while the electromagnetic apparatus114is manually moved into position prior, for example by a suitable mechanism such as a jack or crane. In this way, an input support member is configured to support the electromagnetic apparatus input when disassembled from the transmission and allow for rotation of the rotor during assembly to and disassembly from the gearbox in an operational turbine.

Thus, it should be appreciated that the rotor support allows the generator to be assembled separately from the gearbox, thereby enabling the generator/alternator to be produced in a different location from the gearbox. Further, the rotor support, it is possible to assemble and test the generator at its place of manufacture. Additionally, the rotor support also allows for field removal of the generator from the gearbox. As the generator is removed from the gearbox, the rotor drops onto the rotor support. This allows the gearbox or the generator to be removed as a component, thus allowing a smaller crane to be used for servicing up-tower, if desired. In this way, the complexity and time in the process of removing the generator is reduced, for example allowing removal/service in a few hours.

In one embodiment, the clearance between the rotor and the rotor support in the assembled position can range from +0.0005 inches to the maximum angular misalignment range of the electromagnetic apparatus bearing186, discussed in greater detail herein with regard toFIG. 5.

Additionally a rotor stop159may be included in the rotor. The rotor stop may be coupled to the rotor by a suitable coupling or may be integrally formed as part of the rotor. The rotor stop may be configured to reduce the likelihood of the rotor sliding out of the stator when the electromagnetic apparatus is disassembled. This feature allows the generator to be more easily removed from the turbine head.

In some examples, the electromagnetic apparatus114may generate a substantially steady (e.g. fixed) frequency alternating current (A/C), such as 50 or 60 Hz, for power transmission and functional power usage in a power grid. Various generator configurations may be used to achieve a fixed frequency A/C output.

In a first example, a synchronous generator may be used in conjunction with a power control system. The power control system is configured to convert a variable frequency A/C input to a fixed frequency A/C output. The power control system may be integrated into the synchronous generator or may be coupled exterior to the synchronous generator. Additionally, the power control system may include a frequency generator, having a slip ring, coupled between the generator and the electrical system.

In a second example, a synchronous generator may be used in conjunction with a hydraulic or electric torque control system, such as a hydraulic torque converter. The torque control system may be configured to convert the variable speed rotational input into a single speed output rotational speed, allowing for fixed frequency power generation in the synchronous generator. The torque control system may be rotationally coupled between the transmission and the generator. In some examples, the torque control system may be at least partially integrated into the transmission.

In a third example, an asynchronous generator, such as a double fed induction type generator, may be utilized, where the asynchronous generator is configured to produce a fixed frequency A/C output.

Continuing withFIG. 3, a rotor coupling160may be positioned at an exterior portion of the rotor, as further shown inFIG. 11. The rotor coupling may be configured to attach to the drive coupling. Bolts161may be used to attach the drive coupling to the rotor coupling. A coupling frame162, configured to attach the transmission housing and the stator frame, may also be included in the power generation assembly.

In this example, a flexible rotor coupling is utilized, reducing misalignment and loading from the generator from negatively influencing the transmission or visa versa. However, it can be appreciated that a rigid rotor coupling may be utilized. Further in this example, a plurality of bolts may be used to couple the rotor coupling to the drive coupling. Still further, the rotor coupling may have the shape of a plate or flange. In one example, the rotor coupling may be in axial alignment with a radial line or plane of symmetry180of the transmission bearing. In this way, the amount of radial load from the rotor may be more evenly distributed on the transmission bearing, decreasing the influence of the rotor weight on unintended movement of the transmission output shaft.

In one example, the rotating coupling of couplings160and142fixes the generator rotor shaft to the rotating output shaft of the gearbox centers the gravitational forces of the generator above the center of the transmission bearing in a way as reduce any bending moment on the output sun gear of the gearbox. This rotating coupling may contain electrical insulation to reduce stray currents from entering the gearbox system.

Referring now toFIG. 4, the transmission and electromagnetic apparatus are shown assembled, illustrating the integrated and compact structure obtained. As noted above, the transmission input and outputs are co-axially aligned, which in this example enables a pitch control tube158. The pitch control tube158is shown directed through the center of the generator and the transmission (e.g. through the rotor, transmission output shaft, and transmission input), along the central rotating axis119. In this way, the pitch control tube traverses from the transmission input through the generator and is inside the center of the planetary transmission and electromagnetic apparatus. The pitch control tube may include various conduits (not shown), such as electric wires and/or hydraulic lines, configured to adjust the orientation (e.g. pitch) of the rotor blades. The conduits may be coupled to a suitable controller located in the rotor hub, nacelle or at a down-tower location. Referring now toFIG. 5, it shows selected components of the transmission and electromagnetic apparatus, along with a number of forces, which may be generated, acting upon the components of transmission and electromagnetic apparatus.

The forces include an axial load164from the gears in the transmission, such as the exterior portion of the planet gears and the sun gear, due to their helical engagement. Additionally, the forces include static radial loading166from the weight of the sun gear as well as dynamic loading168with radial components, due to the meshing tolerances in the gear-train, as well as various coupling and housing tolerances. Further, radial loads170from the rotor weight and imbalanced loads, including radial and axial components, in the rotor may be included in the forces.

As noted above, the various bearings in the power generation system may perform a number of functions, serving in multiple capacities. First, the bearings allow various components to rotate. Secondly, the bearings may effectively react at least some of the aforementioned forces (e.g. loads) in the power generation system, decreasing the stresses on various components of the power generation system, increasing the components lifespan.

In one particular example, the transmission bearing174may react the axial loads from the gear-train130, any axial loads from the rotor, and the radial loads from the transmission and the electromagnetic apparatus114. However, the positioning of the transmission bearing, including the axial and radial location, may affect stresses on various components of the transmission. Due to various tolerances in the transmission, as previously mentioned, the sun gear may move in a number of radial directions during operation of the power generation system. This movement is desirable to maintain proper gear contact. If the electromagnetic apparatus loads on the transmission bearing exceed the transmission loads on the transmission bearing, the electromagnetic apparatus can influence the meshing between the sun gear and the exterior portion of the planet gears and cause increased noise, premature wear, and additional vibrations. In one example, imbalanced loads in a gear-train may be determined based on a combination of gear manufacturing tolerances, housing manufacturing errors, and the additional kinematic forces due to gear meshing and the associated errors under speed, such as using factors referred to as Kgammaand Kvas referenced in ISO standards, such as ISO 6336.

As shown in table one below, the static radial loading from the gear-train on the transmission bearing may be represented as variable Fradial. The axial loads from the gear-train on the transmission bearing may be represented as variable Faxial. The percentage of dynamic loading from the gear-train misalignments and manufacturing tolerances on the transmission bearing may be represented as variables Kgammaand Kv. The static and dynamic loading from the rotor on the transmission bearing may be represented as variables Fr-staticand Fr-dynamic, respectively.

TABLE 1FradialRadial Loading From Gear-trainFaxialAxial Loading From Gear-trainKgamma, KνDynamic Loading From Gear-trainFbearing∠Taper or Spherical Bearing ConeAngle (Sin or Cos depending onaxial or radial loading)Fr-staticStatic Loading From RotorFr-dynamicDynamic Loading From Rotor

In some examples, the electromagnetic apparatus loads, such as rotor loads, on the transmission bearing may not exceed the transmission loads on the transmission bearing, expressed by equation1shown below,
Fr-static+Fr-dynamic<(Kgamma+Kv)×Fradial+(Faxial×Fbearing ∠)  (1)

It can be appreciated that the aforementioned equation is exemplary in nature and alternate approaches may be used to calculate the location of the coupling and various other components to properly distribute loads in the wind turbine.

Therefore, the longitudinal position along the axis of rotation of the transmission output, the diameter of the bearing, and/or a tapered angle190of the rollers within the bearing, may all be selected and sized/positioned to decrease the influence of the electromagnetic apparatus on the transmission, and allow play in the sun gear motion. The tapered angle may include an angle between the axis of rotation of a roller included in a row of the tapered roller bearing and a longitudinally positioned line such as the axis of rotation of the transmission output.

Additionally, at least one of the rollers included in the first row and one of the rollers included in the second row are positioned such that the lines182and184, drawn perpendicular to their respective axes of rotation, form an intersection at a desired point185. In one example, the intersection of the line from a cylinder in the first row and the line from a cylinder in a second row intersect at a point185on the central axis of rotation119.

In this way, it is possible to integrate the bearing support of the rotor and the transmission output, while still providing sufficient play at the front end of the sun gear so that motion of the planets can allow the planet-gear-interface-area of the sun gear to have an active location during operation.

Note that the above example embodiments are to illustrate various concepts which can include various modifications. For example, the generator may include a rail system that has wheels on the generator and rails on the wind turbine bed plate to allow easy removal of the generator without use of a crane. This would allow disassembly of the generator and then removal of the gearbox or generator as a separate component, thus allowing a smaller crane truck and lowering repair costs significantly.