Rotor handling device, system and method

Abstract

A rotor handling device for handling a rotor of a wind turbine comprises a track assembly comprising an arcuate track. The arcuate track extends between a top of a rotor hub of the rotor and a front of the rotor hub when the rotor is mounted on the wind turbine and the track assembly is mounted on the rotor hub. The rotor handling device further has a carriage on which the arcuate track is movably mounted. The carriage has: at least one lifting lug for connection to a lifting device; at least one wheel on which an underside of the arcuate track rides; and, a motor operatively connected to the arcuate track to drive the arcuate track on the carriage. The device allows turning a rotor so that rotor blades of the rotor are in a substantially horizontal plane without using a ground-based crane.

Description

[0001] ROTOR HANDLING DEVICE, SYSTEM AND METHOD

[0002] Cross-reference to Related

[0003]

[0004] This application claims the benefit of USSN 63 / 747,172 filed January 20, 2025, the entire contents of which is herein incorporated by reference.

[0005] Field

[0006] This application relates to wind turbines.

[0007] Replacement (exchange) of a main bearing of a wind turbine requires removing a rotor from the main bearing. Rotor removal is usually accomplished by connecting the rotor to crane, disconnecting the rotor from the main bearing and then moving the rotor away from the main bearing to provide access to the main bearing. The rotor can either be lowered to the ground while the main bearing exchange operation proceeds, or the rotor can remain suspended at or near a top of the wind turbine, but at a distance from the main bearing. In both cases, the rotor generally needs to be turned so that the wind turbine’s rotor blades are in a substantially horizontal plane instead of a substantially vertical plane. Turning the rotor is usually accomplished by connecting a tip-end of one of the rotor blades to a ground-based tailing crane. However, utilization of a ground-based tailing crane significantly increases the expense of the main bearing exchange operation.

[0008] There remains a need for a simple, less expensive method and device to assist with turning a rotor so that rotor blades of the rotor can be moved to a substantially horizontal plane after the rotor is removed from a main bearing of a wind turbine.

[0009] A rotor handling device for handling a rotor of a wind turbine comprises: a track assembly comprising an arcuate track, the arcuate track extending between a top of a rotor hub of the rotor and a front of the rotor hub when the rotor is mounted on the wind turbine and the track assembly is mounted on the rotor hub; and, a carriage on which the arcuate track is movably mounted, the carriage comprising: at least one lifting lug for connection to a lifting device, the lifting device connectable to the at least one lifting lug from above the at least one lifting lug; at least one wheel on which an underside of the arcuate track rides; and, a motor operatively connected to the arcuate track to drive the arcuate track on the carriage.A system for handling a rotor of a wind turbine comprises a rotor handling device as defined above, and a lifting device connected to carriage.

[0010] A method for handling a rotor of a wind turbine comprises: mounting the rotor handling device as defined above on a rotor hub of the rotor; and, operating the motor of the rotor handling device to move the arcuate track on the carriage thereby turning the rotor to change orientation of rotor blades attached to the rotor hub.

[0011] In some embodiments, the arcuate track comprises a strip curved in an arc to permit the arcuate track to smoothly travel on the carriage longitudinally along a length of the arcuate track. In some embodiments, the arc is a single arc with respect to an arc center. In some embodiments, the arc center coincides with a center of gravity of the rotor when the track assembly is mounted on the rotor hub. Having the arc center coincide with the center of gravity of the rotor means that the motor is only needed to drive the arcuate track through the carriage along a drive path that is horizontal and tangential to the arc. The full weight of the rotor is therefore supported by the at least one wheel and the motor is only needed to overcome the rolling resistance and inertia of the rotor, thereby significantly reducing the size required for a drive system, including the motor. Safety of the device significantly improved because a failure of the drive system will not cause the rotor to move in an uncontrolled manner as the rotor is always in a stable position, with the center of gravity of the rotor positioned directly beneath the at least one lifting lug where the lifting device is connected to the rotor handling device.

[0012] In some embodiments, the arcuate track comprises arcuate sidewalls and an arcuate floor that together form an arcuate channel with bottom edges of the arcuate sidewalls extending past the floor along at least a portion of the length of the arcuate track. In some embodiments, the bottom edges of the sidewalls (i.e., inner edges of the sidewalls with respect to the center of the arc) form the structures of the arcuate track that engage the carriage for the arcuate track to be movable on the carriage. In some embodiments, the bottom edges of the sidewalls are rails that ride on the at least one wheel of the carriage. In some embodiments, a motor engagement structure (e.g., a chain, a belt, a cable, regularly spaced apertures), which is part of the drive system, is disposed in the arcuate channel, the motor engagement structure being engaged with the motor so that operation of the motor drives the arcuate track on the carriage. In some embodiments, the arcuate sidewalls and the arcuate floor together form upper and lower arcuate channels. In some embodiments, the motor engagement structure is disposed in the upper arcuate channel.The motor is part of the drive system and is operatively connected to the arcuate track to drive the arcuate track on the carriage. In some embodiments, the motor is a reversible motor. In some embodiments, the motor is a variable speed motor. In some embodiments, the motor is a hydraulic motor or an electric motor. In some embodiments, the motor is provided with an on-board power source, for example a battery.

[0013] In some embodiments, the rotor handling device comprises a control system for one or more of: switching the motor on and off; changing rotational direction of the motor; changing motor speed; and any other powered function of the motor or other component of the rotor handling device. In some embodiments, the control system is controlled remotely using a remote control or a wired connection. In some embodiments, the control system comprises a controller that receives and processes signals from a remote control or through a wired connection. In some embodiments, the controller comprises a programmed logic controller (PLC) and a computer memory having a program for automatically controlling the motor and any other powered components of the rotor handling device. In some embodiments, the control system comprises one or more sensors configured to sense environmental conditions (e.g., wind speed, temperature and the like) and / or a condition of the rotor handling device (e.g., a condition of the motor, a position of the arcuate track and the like). In some embodiments, the control system for the rotor handling device is interfaced with a control system for the lifting device so that operation of the two systems can be synchronized for improved handling of the rotor.

[0014] In some embodiments, the motor comprises a drive shaft connected to at least one structure (e.g., a sprocket, a reel or other chain-gripping arrangement) that engages the motor engagement structure of the arcuate track. In some embodiments, the drive shaft is connected by one or more drive belts and / or drive chains to the at least one structure that engages the motor engagement structure. In some embodiments, the carriage comprises a carriage housing that houses the at least one structure that engages the motor engagement structure. In some embodiments where the arcuate track comprises a chain extending longitudinally and arcuately between ends of the arcuate track, the motor is operatively connected to the arcuate track by at least one sprocket or other chain-gripping arrangement that engages links of the chain. In some embodiments, the motor engagement structure (e.g., chain, belt, cable or the like) is tensioned between the ends of the arcuate track. In some embodiments, the motor engagement structure comprises a tensioner to tension the motor engagement structure between the ends of the arcuate track.

[0015] In some embodiments, the track assembly further comprises a track hub located radially inwardly from the arcuate track. In some embodiments, the track hub comprises afront hub mount configured to mount the track assembly on the front of the rotor hub. In some embodiments, the front hub mount is configured to be securely attached to the front of the rotor hub, for example by one or more pins (e.g., bolts, screws, rivets, cotter pins, or the like). Suitable configurations of the front hub mount comprise plates, brackets, beams, or the like. In some embodiments, the front hub mount is mounted to existing mounting structures on the front of the rotor hub. In some embodiments, the front hub mount comprises an abutment face that abuts the front of the rotor hub. In some embodiments, the front hub mount comprises a removable spacer situated between the track hub and the front of the rotor hub. The removable spacer is sized for a particular model of wind turbine. Because each model or make of wind turbine has a differently configured rotor hub, several different spacers can be designed so that the rotor handling device can be used with many different makes and models of wind turbines. In some embodiments, the track hub is secured to the arcuate floor of the arcuate track. In some embodiments, the track hub is disposed within the lower arcuate channel of the arcuate track while providing sufficient space for the carriage to engage the bottom edges of the sidewalls. In some embodiments, the track assembly further comprises one or a plurality of spokes connecting the arcuate track to the track hub.

[0016] In some embodiments, one or more adapter blocks located at the front and / or top hub mounts are used to shift the track assembly device forward or rearward on different makes and models of rotors to make the arc center of the arcuate track coincide with the center of gravity of the rotor. Different adapter blocks can be used at the front and top hub mounts permitting re-use of the rotor handling device on various makes and models of rotors.

[0017] In some embodiments, the track assembly further comprises a top hub mount configured to mount the track assembly on the top of the rotor hub. In some embodiments, the top hub mount is configured to be securely attached to the top of the rotor hub, for example by one or more pins (e.g., bolts, screws, rivets, cotter pins, or the like). Suitable configurations of the top hub mount comprise plates, brackets, beams, or the like. In some embodiments, the top hub mount is mounted to existing mounting structures on the top of the rotor hub. In some embodiments, the top hub mount comprises a bracket that is pinned to a top of the rotor hub. In some embodiments, the ends of the arcuate track are a proximal end at which the top hub mount is located and a distal end. In some embodiments, the track assembly further comprises a platform on which operators can stand. In some embodiments, the platform is located at the proximal end of the arcuate track and proximate the top hub mount.In some embodiments, the carriage comprises a carriage bracket having transversely opposed bracket side arms connected by a bracket top arm. In some embodiments, the carriage bracket straddles side edges of the arcuate track so that the bracket side arms extend below the arcuate track. In some embodiments, the carriage supports the arcuate track from below the arcuate track. The carriage comprises at least one wheel on which an underside of the arcuate track rides. In some embodiments, the at least one wheel is rotationally mounted on a lower end of at least one of the bracket side arms. In some embodiments, the at least one wheel comprises at least two transversely space-apart wheels on which opposite longitudinally-extending transverse edges of the arcuate track roll. In some embodiments, the at least two transversely space-apart wheels comprise at least two sets of the two transversely space-apart wheels, the at least two sets longitudinally spaced-apart on the arcuate track. In some embodiments, the at least one wheel engages the bottom edges of the sidewalls of the arcuate track so that the arcuate track is movable on the carriage by virtue of the at least one wheel engaging the bottom edges of the sidewalls.

[0018] Prior art devices and methods for turning a rotor depend on taglines or technicians physically pushing or pulling on the tip of the bottom rotor blade to rotate the rotor, which poses a safety risk for the technicians moving the large objects, and which is more subject to lower wind speed limits, thereby limiting the prior art devices and methods to smaller rotors with less inertia. Utilizing a motorized carriage as described herein to move the arcuate track on the carriage permits handling larger rotors in windier conditions while being much safer, not requiring technicians to move large objects.

[0019] The system for handling a rotor of a wind turbine comprises the rotor handling device together with a lifting device. The lifting device is connected to carriage of the rotor handling device. In some embodiments, the lifting device comprises a lifting line connected to the at least one lifting lug of the carriage. In some embodiments, the lifting line comprises a connector (e.g., a hook or the like), which releasably connects to the at least one lifting lug. In some embodiments, the system comprises a stabilizer connected to the carriage and a nacelle of the wind turbine or a structure in the nacelle. In some embodiments, the structure in the nacelle comprises the lifting device and the stabilizer connects the carriage to the lifting device. In some embodiments, the stabilizer comprises a rod, a line, a beam, or any combination thereof. In some embodiments, the lifting device comprises a nacellemounted crane. However, it is instead possible to use a ground-based or nacelle-mounted winch, or a ground-based crane. In any event, the lifting device should be connectable to the carriage from above the carriage.The rotor handling device and system may be used in a method for handling a rotor of a wind turbine. The method comprises mounting the rotor handling device on a rotor hub of the rotor, and operating the motor of the rotor handling device to move the arcuate track on the carriage thereby turning the rotor to change orientation of rotor blades attached to the rotor hub. In some embodiments, the method further comprises connecting the carriage to a lifting device. In some embodiments, the method further comprises disconnecting the rotor from a main bearing of the wind turbine. Once the rotor handling device is mounted on the rotor hub, the lifting device is connected to the carriage and the rotor is disconnected from the main bearing, the lifting device is operated to hold the rotor handling device, and therefore the rotor, horizontally away from the wind turbine. Operating the motor of the rotor handling device causes the arcuate track to translate arcuately through the carriage to change the orientation of the rotor blades causing the rotor blades to move from being in a substantially vertical plane to being in a substantially horizontal plane. Operating the motor in reverse causes the arcuate track to translate arcuately through the carriage to change the orientation of the rotor blades causing the rotor blades to move from being in the substantially horizontal plane to being in the substantially vertical plane so that the rotor can be reconnected to the main bearing.

[0020] In some embodiments, the method is used to remove the rotor from the main bearing and store the rotor up-tower near the wind turbine tower while the main bearing is being replaced or maintained. In some embodiments of such a method, the following steps are followed:

[0021] a. connect the lifting device to the rotor handling device and lift the rotor handling device to the rotor hub;

[0022] b. mount the rotor handling device on the rotor hub of the rotor;

[0023] c. disconnect the rotor from the main bearing of the wind turbine;

[0024] d. using the lifting device, move the rotor handling device, and therefore the rotor, horizontally away from the main bearing;

[0025] e. while lowering the rotor handling device using the lifting device, and therefore the rotor therewith, to obtain clearance from the main bearing and the nacelle, operate the motor to drive the arcuate track through the carriage thereby turning the rotor from an orientation where the rotor blades are in a substantially vertical plane to an orientation where the rotor blades are in a substantially horizontal plane; and,f. perform the main bearing exchange or maintenance.

[0026] After performing the main bearing exchange or maintenance, the steps are reversed to re-install the rotor in the main bearing. Thus, for re-installation, the following steps are followed:

[0027] 1. while raising the rotor handling device using the lifting device, and therefore the rotor therewith, operate the motor in reverse to drive the arcuate track back through the carriage thereby turning the rotor from the orientation where the rotor blades are in the substantially horizontal plane to the orientation where the rotor blades are in the substantially vertical plane;

[0028] 2. using the lifting device, move the rotor handling device, and therefore the rotor, horizontally toward from the main bearing;

[0029] 3. connect the rotor to the main bearing of the wind turbine;

[0030] 4. dismount the rotor handling device from the rotor hub of the rotor;

[0031] 5. lift the rotor handling device away from the rotor hub, for example to the ground, and disconnect the lifting device from the rotor handling device.

[0032] The rotor handling device provides a simple method to assist with turning a rotor so that rotor blades of the rotor are in a substantially horizontal plane when the rotor is removed from a main bearing of a wind turbine. Although a ground-based crane can be used to perform the method, the rotor handling device provides the option of not using a ground-based crane thereby reducing the expense of performing the main bearing exchange or maintenance.

[0033] Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.

[0034] Brief Description of the Drawings

[0035] For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:

[0036] Fig. 1 depicts a front perspective view of a rotor handling device.Fig. 2 depicts another front perspective view of the rotor handling device of Fig. 1. Fig. 3 depicts a rear perspective view of the rotor handling device of Fig. 1.

[0037] Fig. 4 depicts a rear perspective view of the rotor handling device of Fig. 1 including a spacer.

[0038] Fig. 5 depicts a magnified view of a chain drive of the rotor handling device of Fig.

[0039] 1.

[0040] Fig. 6 depicts a front perspective view of a wind turbine rotor having the rotor handling device of Fig. 1 mounted thereon.

[0041] Fig. 7 depicts a magnified view of Fig. 6.

[0042] Fig. 8 depicts a front view of Fig. 6.

[0043] Fig. 9A depicts a front perspective view of a first step in a method of removing a rotor from a main bearing of a wind turbine utilizing the rotor handling device of Fig. 1.

[0044] Fig. 9B depicts a side view of Fig. 9A.

[0045] Fig. 10A depicts a front perspective view of a second step in the method of removing the rotor from the main bearing of the wind turbine utilizing the rotor handling device of Fig.

[0046] 1.

[0047] Fig. 10B depicts a side view of Fig. 10A.

[0048] Fig. 10C depicts the second step shown in Fig. 10A including further use of a stabilizer.

[0049] Fig. 11 A depicts a front perspective view of a third step in the method of removing the rotor from the main bearing of the wind turbine utilizing the rotor handling device of Fig.

[0050] 1.

[0051] Fig. 11 B depicts a side view of Fig. 11 A.

[0052] Fig. 11C depicts the third step shown in Fig. 11A including further use of the stabilizer.Detailed

[0053] With reference to the Figures, an embodiment of a rotor handling device 1 for handling a rotor 101 of a wind turbine 100 comprises a track assembly 10 comprising an arcuate track 20. The rotor handling device 1 also comprises a carriage 50 on which the arcuate track 20 is movably mounted such that the arcuate track 20 is movable through the carriage 50. The track assembly 10 comprises a top hub mount 11 for securely mounting the track assembly 10 on a top of a rotor hub 102, and a front hub mount 13 for securely mounting the track assembly 10 on a front of the rotor hub 102. The top hub mount 11 is illustrated as a bracket that is pinned to an existing structure on the top of the rotor hub 102. The front hub mount 13 is illustrated as a plate having an abutment face 13a with a lower ledge 13b, which are bolted to existing structures on the front of the rotor hub 102.

[0054] The arcuate track 20 comprises a proximal end 21 and a distal end 22, the arcuate track 20 curving smoothly as a single arc between the ends 21, 22 and around a center point spatially located radially inwardly toward or in the rotor hub 102. The center point coincides with the center of gravity of the rotor 101. The arcuate track 20 comprises transversely spaced-apart sidewalls 23 having longitudinally-extending bottom edges 24 that follow the arc, the arcuate track 20 also comprising an arcuate floor 27 extending transversely between the sidewalls 23. The floor 27 and the transversely spaced-apart sidewalls 23 together form upper arcuate channel 25 and a lower arcuate channel 26. A motor engagement structure in the form of a chain 28 in a chain guide 28a is disposed in the upper arcuate channel 25 and extends longitudinally in the arcuate track 20 between the proximal end 21 and the distal end 22 of the arcuate track 20. The chain 28 is secured in the upper arcuate channel 25 by nut and bolt arrangements whereby bolts extending from ends of the chain 28 extend through end walls of the arcuate track 20 to be secured in place by nuts. The chain 28 is suitably tensioned by a tensioner 30 located between the chain 28 and the nut and bolt arrangement at the proximal end 21 of the arcuate track 20.

[0055] The track assembly 10 further comprises a track hub 15 to which the arcuate track 20 is connected by a plurality of spokes 16. The spokes 16 are securely connected to the arcuate floor 27 within the lower arcuate channel 26. The spokes 16 are sufficiently narrow as to be sufficiently transversely spaced away from the sidewalls 23 inwardly into the lower arcuate channel 26 so that the bottom edges 24 the sidewalls 23 can function as rails that ride freely on the carriage 50 when the arcuate track 20 is mounted on the carriage 50. The front hub mount 13 is securely mounted to the track hub 15 such that the abutment face 13a faces toward the front of the rotor hub 102. For some makes and models of wind turbine rotors, the front hub mount 13 comprises a removable spacer 31 (see Fig. 4) situatedbetween the track hub 15 and the front of the rotor hub 102 to fill a gap between the abutment face 13a and the front of the rotor hub 102. The spacer 31 has a similar configuration to the front hub mount 13, the spacer 31 abutting the abutment face 13a of the front hub mount 13 and having a spacer abutment face 31a and a spacer lower ledge 31 b that interact with the front face of the rotor hub 102 in a similar manner as the front hub mount 13 to secure the track assembly 10 to the front face of the rotor hub 102. The top hub mount 11 is situated at and connected to the proximal end 21 of the arcuate track 20. In addition, the track assembly 10 further comprises a platform 32 located at the proximal end 21 of the arcuate track 20 and proximate the top hub mount 11 on which operators can stand when connecting the rotor handling device 1 to the rotor hub 102.

[0056] The carriage 50 comprises a carriage bracket 51, a carriage housing 53, lifting lugs 59 for connection to a lifting device 110, a plurality of wheels 60 on which the bottom edges 24 of the sidewalls 23 of the arcuate track 20 ride, and a motor 70 operatively connected to the chain 28 to drive the arcuate track 20 on and through the carriage 50.

[0057] The carriage bracket 51 comprises transversely opposed bracket side arms 51b, 51c connected by a bracket top arm 51a. The carriage bracket 51 straddles the sidewalls 23 of the arcuate track 20 so that the bracket side arms 51b, 51c extend below the bottom edges 24 of the sidewalls 23 of the arcuate track 20. The wheels 60 are rotationally mounted on lower ends of the bracket side arms 51b, 51c by axles 61. The bottom edges 24 of the sidewalls 23 of the arcuate track 20 rest on the wheels 60 so that the arcuate track 20 rides freely on the wheels 60. The wheels 60 are grouped as two sets 63, 64 of two transversely space-apart wheels. The two sets 63, 64 are longitudinally spaced-apart on the arcuate track 20.

[0058] The motor 70 (e.g., a reversible hydraulic or electric motor) is mounted on the carriage housing 53 and has a drive shaft (not shown) that extends into the carriage housing 53. Mounted on the drive shaft is a sprocket or other chain-gripping arrangement (not shown) having teeth or other rotatable chain-gripping structures that engage links of the chain 28. In the illustrated embodiment, the carriage housing 53 comprises an electromechanical chain drive characterized by a triangular arrangement of rotatable chain link grippers through which the chain 28 is looped in an omega-shape. The commercially available TECDOS™ omega drive is an example of such an electro-mechanical chain drive. Operation of the motor 70 rotates the drive shaft, which rotates the sprocket (or other chain-gripping arrangement). Because the teeth of the sprocket (or the chain-gripping structures of the other chain-gripping arrangement) are engaged with the links of the chain 28, which are correctly spaced in relation to spacing of the teeth around the sprocket (or tothe spacing of the chain-gripping structures of the other chain-gripping arrangement), and the chain 28 is fixed in the upper arcuate channel 25 of the arcuate track 20, operation of the motor 70 drives the arcuate track 20, whose bottom edges 24 rest on the wheels 60, through the carriage 50, which surrounds much of the arcuate track 20. Thus, during operation, the track assembly 10, together with the rotor 101 to which the track assembly 10 is securely attached, moves when the motor 70 is operated.

[0059] Fig. 6 to Fig. 8 depict views of the rotor handling device 1 mounted on the rotor hub 102 of the rotor 101 of the wind turbine 100. The rotor handling device 1 is initially installed atop the rotor hub 102 flanked between two rotor blades 103b with a third rotor blade 103a pointing vertically downward. The rotor handling device 1 is installed in an initial installation configuration with the carriage 50 at the proximal end of the arcuate track 20 where the top hub mount 11 is securely attached to the rotor hub 102. The arcuate track 20 extends outwardly horizontally beyond the third rotor blade 103a and curves downwardly through about a quarter arc of a circle so that the distal end 22 of the arcuate track 20 initially points downward. In the initial installation configuration, the platform 32 is oriented horizontally so that operators can easily stand on the platform 32.

[0060] Fig. 9A to Fig. 11C illustrates a system and method for removing the rotor 101 from a main bearing 106 of the wind turbine 100 utilizing the rotor handling device 1.

[0061] In a first step (Fig. 9A and Fig. 9B), the rotor handling device 1 at ground level is connected to the lifting device 110, which comprises a hook assembly 111 configured to hook on to the lifting lugs 59, and the lifting device 110 is operated to lift the rotor handling device 1 up to the rotor 101. The lifting device 110 is mounted in a nacelle 105 atop a tower 104 of the wind turbine 100. The lifting device 110 is operated to position the rotor handling device 1 so that the proximal end of the arcuate track 20 is located at the top of the rotor hub 102, where the rotor handling device 1 is installed on the rotor hub 102 in the initial installation configuration by attaching the top hub mount 11 securely to the top of the rotor hub 102, and attaching the front hub mount 13 securely to the front of the rotor hub 102. The rotor blades 103a, 103b are oriented in a substantially vertical plane when connected to the main bearing 106, although under standard operation, the plane occupied by the rotor blades 103a, 103b may be tilted somewhat from the vertical plane. Once the rotor handling device 1 is secured to the rotor hub 102, the rotor 101 is disconnected from the main bearing 106 and the lifting device 110 is operated to move the rotor 101 horizontally away from the nacelle 105. The rotor blades 103a, 103b are still oriented in a substantially vertical plane.In a second step (Fig. 10A and Fig. 10B), the lifting device 110 is operated to lower the rotor handling device 1 with the rotor 101 attached thereto thereby also lowering the rotor 101. At the same time, the motor 70 of the rotor handling device 1 is operated, for example by remote control, causing the arcuate track 20 to rotate through the carriage 50 in a direction toward the tower 104. The carriage 50 connected to the lifting device 110 does not move except for being lowered by the lifting device 110. The carriage 50 does not move on the arcuate track 20. Rather, the arcuate track 20 moves on the carriage 50. As the arcuate track 20 rotates and follows an arcuate path that is the same as the arc of the arcuate track 20, the rotor 101 attached thereto also rotates, turning the rotor 101 so that the plane occupied by the rotor blades 103a, 103b becomes more horizontal. The two rotor blades 103b flanking the rotor handling device 1 are in a V-shaped configuration with the tower 104 being flanked by the two rotor blades 103b as the rotor 101 rotates with the arcuate track 20.

[0062] In a third step (Fig. 11A and Fig. 11B), the lifting device 110 is operated to hold the rotor handling device 1 keeping the carriage 50 in place while the motor 70 is operated to cause the arcuate track 20 to continue to rotate through the carriage 50 in a direction toward the tower 104 until the carriage 50 is proximate the distal end 22 of the arcuate track 20 and the rotor blades 103a, 103b are oriented in a substantially horizontal plane with the two rotor blades 103b flanking the tower 104. The rotor 101 is held in this position until the main bearing work is completed.

[0063] After completion of the main bearing work, the steps described above are reversed to reconnect the rotor 101 to the main bearing 106.

[0064] With reference to Fig. 10C and Fig. 11C, in a variation of the method described above, an umbilical 80 is attached between the lifting device 110 and the carriage 50 to help stabilize the carriage 50 after the second step is completed. The umbilical 80 may be a line or a stiff rod, preferably a stiff rod, and is connected at one end to a connecting post 81 on the lifting device 110 and to an umbilical lug 57 on the carriage 50 (see Fig. 5). The umbilical 80 is particularly useful in windy conditions to ensure that that the rotor 101 does not move too much during the main bearing work.

[0065] The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.

Claims

Claims:

1. A rotor handling device for handling a rotor of a wind turbine, the device comprising:a track assembly comprising an arcuate track, the arcuate track extending between a top of a rotor hub of the rotor and a front of the rotor hub when the rotor is mounted on the wind turbine and the track assembly is mounted on the rotor hub; and,a carriage on which the arcuate track is movably mounted, the carriage comprising:at least one lifting lug for connection to a lifting device, the lifting device connectable to the at least one lifting lug from above the at least one lifting lug;at least one wheel on which an underside of the arcuate track rides; and, a motor operatively connected to the arcuate track to drive the arcuate track on the carriage.

2. The rotor handling device of claim 1 , wherein the track assembly further comprises a track hub located radially inwardly from the arcuate track, the track hub comprising a front hub mount configured to mount the track assembly on the front of the rotor hub.

3. The rotor handling device of claim 2, wherein the front hub mount comprises an abutment face that abuts the front of the rotor hub and is configured to be securely attached to the front of the rotor hub.

4. The rotor handling device of claim 2 or claim 3, wherein the front hub mount comprises a removable spacer situated between the track hub and the front of the rotor hub.

5. The rotor handling device of any one of claims 2 to 4, wherein the track assembly further comprises one or a plurality of spokes connecting the arcuate track to the track hub.

6. The rotor handling device of any one of claims 1 to 5, wherein the track assembly further comprises a top hub mount configured to mount the track assembly on the top of the rotor hub.

7. The rotor handling device of claim 6, wherein the top hub mount comprises a bracket that is pinned to a top of the rotor hub.

8. The rotor handling device of any one of claims 1 to 7, wherein the arcuate track has an arc center that coincides with a center of gravity of the rotor when the track assembly is mounted on the rotor hub.

9. The rotor handling device of any one of claims 1 to 8, wherein the carriage comprises a carriage bracket having transversely opposed bracket side arms connected by a bracket top arm, the carriage bracket straddling side edges of the arcuate track so that the bracket side arms extend below the arcuate track, the at least one wheel rotationally mounted on a lower end of at least one of the bracket side arms.

10. The rotor handling device of any one of claims 1 to 9, wherein the at least one wheel comprises at least two transversely space-apart wheels on which opposite longitudinally-extending transverse edges of the arcuate track roll.

11. The rotor handling device of claim 10, wherein the at least two transversely space-apart wheels comprises at least two sets of the two transversely space-apart wheels, the at least two sets longitudinally spaced-apart on the arcuate track.

12. The rotor handling device of any one of claims 1 to 11, wherein the arcuate track comprises a chain extending longitudinally and arcuately between ends of the arcuate track, wherein the motor is operatively connected to the arcuate track by at least one sprocket that engages links of the chain.

13. The rotor handling device of claim 12, wherein the chain is tensioned between the ends of the arcuate track.

14. A system comprising a rotor handling device as defined in any one of claims 1 to 13, and a lifting device connected to carriage.

15. The system of claim 14, wherein the lifting device comprises a nacelle-mounted crane.

16. A method for handling a rotor of a wind turbine, the method comprising:mounting the rotor handling device as defined in any one of claims 1 to 13 on a rotor hub of the rotor; and,operating the motor of the rotor handling device to move the arcuate track on the carriage thereby turning the rotor to change orientation of rotor blades attached to the rotor hub.

17. The method of claim 16, wherein:the rotor is disconnected from a main bearing of the wind turbine;the carriage is connected to a lifting device; and,the lifting device holds the rotor handling device, and therefore the rotor, horizontally away from the wind turbine so that operating the motor to change the orientation of the rotor blades causes the rotor blades to move from being in a substantially vertical plane to being in a substantially horizontal plane.

18. The method of claim 17, wherein the lifting device comprises a nacelle-mounted crane.

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