Field of the invention

The invention relates generally to platforms for the assembly and disassembly of rotating electrical machines. More particularly, the invention relates to a platform for assembling and disassembling a permanent magnet electrical machine that comprises an annular stator comprising two or more stator segments and an annular rotor comprising two or more rotor segments. The invention further relates to a method for disassembling a permanent magnet electrical machine using the platform. The invention further relates to a method for assem- bling a permanent magnet electrical machine using the platform. The invention further relates to a method for transporting a permanent magnet electrical machine using the platform.

Background

The diameter of megawatt-class electrical machines is large, especially in direct-driven wind generators. It is a challenging task to transport such a generator to a wind park. Typically, the wind generators are moved by truck, rail or barge. For offshore wind generators, the large size is normally not a problem, but for onshore wind turbines, the size causes additional challenges and costs. Trucking is often the obvious choice, although the size of the wind generator exceeds normal road transportation limits. The size of the pieces to be transported can be reduced by splitting the generator into segments. However, as the forces between the stator and rotor in permanent magnet generators are high, a conventional assembly of the rotor and stator in wind park conditions is challenging.

Disclosure of the invention The objective of the present invention is to create a platform for assembling and disassembling a permanent magnet electrical machine that allows the assembly and the disassembling of an electrical machine that comprises an annular stator comprising two or more stator segments and an annular rotor comprising two or more rotor segments. In accordance with the first aspect of the invention, there is a new platform for assembling and disassembling a permanent magnet electrical machine. The new platform for assembling and disassembling a permanent magnet electrical machine, whose permanent magnet electrical machine comprises an annular stator comprising two or more stator segments and an annular rotor comprising two or more rotor segments, where either the stator segments or the rotor segments are the radially outer segments and the other are the radially inner segments, comprises at least two frames. The frames are releasably attached to each other with an attaching means. The frames comprise a positioning means for positioning the frames in relation to each other. The frames comprise a first fixing means for fixing the stator segments to the frames and a second fixing means for fixing the rotor segments to the frames so that an axis of rotation of the electrical machine is substantially perpendicular to the platform. Either the first fixing means or the second fixing means, or both, comprises a first element and a second element, which are capable of providing a linear movement with respect to the frames. The technical effect achieved with the platform for assembling and disassembling a permanent magnet electrical machine is that the magnetic forces between the stator segments and rotor segments can be controlled.

Another technical effect achieved with the platform for assembling and disassembling a permanent magnet electrical machine is that during machine disassembly, the platform al- lows moving the radially outer segments of the electrical machine apart from each other while the inner segments are still interconnected. Thus, it is easier to disengage the inner segments from each other. Correspondingly, when assembling the machine, the transportation and assembly platform allows keeping the outer segments of the electrical machine apart from each other when the inner segments of the electrical machine are being inter- connected and moving the outer segments together after interconnecting the inner segments.

According to one embodiment of the invention, a radial width of an air gap between the stator segments and the rotor segments is changeable by means of the first element and the second element. According to one embodiment of the invention, the first element and the second element move linearly with respect to the frames in the direction of an angle bisector of an angle of the radially outer segments or in the direction of an angle bisector of an angle of the interconnected radially outer segments.

According to one embodiment of the invention, the radial width of an air gap between the stator segments and the rotor segments is changeable to a non-uniform radial width of the air gap.

According to one embodiment of the invention, the first elements are fixed to the radially outer segments and the second elements are fixed to the frames.

According to one embodiment of the invention, the first element and the second element are slideable with respect to each other. According to one embodiment of the invention, the first element and the second element comprise a plain bearing linear guide.

According to one embodiment of the invention, the first element and the second element comprise dovetail slides.

According to one embodiment of the invention, the first fixing means is attached to the brake caliper mounts of the stator segment.

According to one embodiment of the invention, the frames comprise a track structure.

According to one embodiment of the invention, the track structure comprises adjustable legs, and the means for adjusting the legs comprise a hydraulic mechanism.

According to one embodiment of the invention, the track structure comprises railway wheels and the frames comprise rails.

According to one embodiment of the invention, the platform comprises four frames.

According to one embodiment of the invention, the frame comprises hollow section tubes.

In accordance with the second aspect of the invention, there is a method for disassembling a permanent magnet electrical machine. The new method uses the invented platform for as- sembling and disassembling a permanent magnet electrical machine. The permanent magnet electrical machine comprises an annular stator comprising two or more stator segments and an annular rotor comprising two or more rotor segments. Either the stator segments or the rotor segments are the radially outer segments and the other are radially inner segments. The electrical machine is transferred to the platform. The stator segments are fixed to the frames by means of the first fixing means. The rotor segments are fixed to the frames by means of the second fixing means. At least two joints of the radially outer segments are released to allow the radially outer segments to be moved. The radially outer segments are separated from each other by a separating means. The outer segments are moved linearly apart by means of the first and the second elements of either the first fixing means or the second fixing means. At least two joints of the radially inner segments are released. The radially inner separate segments are separated from each other by releasing the frames from each other and separating the frames apart by a disconnecting means.

According to one embodiment of the invention, a radial width of an air gap between the stator segments and the rotor segments is changed by moving the radially outer segments radially outwards by means of the first element and the second element. According to one embodiment of the invention, the first element and the second element are moved linearly with respect to the frames in the direction of an angle bisector of an angle of the outer segments or in the direction of an angle bisector of an angle of the interconnected outer segments.

According to one embodiment of the invention, a non-uniform radial width of the air gap is created.

According to one embodiment of the invention, the electrical machine comprises a bearing unit, and the bearing unit is released from the electrical machine before the joints of the radially outer segments are released.

According to one embodiment of the invention, a support structure is fixed to the radially outer segments before releasing the joints of the radially outer segments, and the support structure prevents lateral buckling of the radially outer segments during the separation of the radially outer segments.

According to one embodiment of the invention, the separating means and disconnecting means comprise hydraulic cylinders. In accordance with the third aspect of the invention, there is a method for assembling a permanent magnet electrical machine using the invented platform for assembling and disassembling a permanent magnet electrical machine. In the new method, the electrical machine is disassembled with the invented method for disassembling a permanent magnet electrical machine. The frames are moved together with moving means. The frames are attached together with attaching means. The joints of the radially inner segments are connected. The radially outer segments are moved linearly together by uniting means and by means of the first and the second elements of either the first fixing means or the second fixing means. The joints of the radially outer segments are connected to each other with fastening means. The rotor segments are released from the frames by releasing the second fixing means. The stator segments are released from the frames by releasing the first fixing means.

According to one embodiment of the invention, the bearing unit is transferred and connected to the electrical machine before the rotor segments are released from the frames. In accordance with the fourth aspect of the invention, there is a method for transporting a permanent magnet electrical machine using the invented platform for assembling and disassembling a permanent magnet electrical machine. In the new method, the electrical machine is disassembled with the invented method for disassembling a permanent magnet electrical machine into transportable parts. The transportable parts rest on the frames of the platform and the frames are placed onto transporting means.

According to one embodiment of the invention, the transporting means comprises a truck container, rail container or sea container.

Some other preferred embodiments of the inventions have the characteristics specified in the dependent claims. A number of exemplifying embodiments of the invention are described in the accompanying dependent claims.

Brief description of the drawings The exemplifying embodiments of the invention and their advantages are explained in greater detail below in the descriptions of the specific exemplifying embodiments with the accompanying drawings, in which:

- Figure 1 shows an assembly and disassembly platform; - Figure 2 shows two frames of the assembly and disassembly platform;

- Figure 3 shows the linear movement directions of the first and second elements;

- Figures 4a)-b) show changes in a radial width of an air gap in the electrical machine;

- Figure 5 shows the transfer of a permanent magnet electrical machine to the assembly and disassembly platform; - Figure 6 shows a joint of the radially outer segments and a joint of the radially inner segments;

- Figure 7 shows the radially outer segments and the radially inner segments in a separated stage;

- Figures 8 shows a support structure for a lightweight electrical machine; - Figure 9 shows transporting a platform frame with a truck;

- Figure 10 shows a permanent magnet electrical machine on the assembly and disassembly platform at a site.

Description of exemplifying embodiments

Figure 1 shows an assembly and disassembly platform 1 for a permanent magnet electrical machine 2. The permanent magnet electrical machine 2 comprises an annular stator 3 comprising two or more stator segments 3a-c and an annular rotor 4 comprising two or more rotor segments 4a-b. The annular stator 3 and the annular rotor 4 are concentric with an axis of rotation 1 1. Either the stator segments 3a-c or the rotor segments 4a-b are radially outer segments and the others are radially inner segments. The radially inner segments are configured to be disposed inside the radially outer segments. The platform 1 comprises two frames 5a-b. Figure 2 shows two frames of the assembly and disassembly platform 1 that are ready for attaching. The frames 5a-b are releasably attached to each other with attaching means 7. The shape of the frame 5a-b is rectangular and the side walls 14a-b are longer than the end walls 15a-b. The attaching means 7 can also comprise moving 31 and disconnecting means 33 so that the attaching means 7 are able to push and pull the frames 5a-b. In the figures, the attaching means 7 are hydraulic cylinders. Other possible attaching means 7 comprising moving 31 and disconnecting means 33 are lead screws, ball screws or pneumatic cylinder drives. The frames 5a-b comprise positioning means 8a-b for positioning the frames 5a-b in relation to each other. The positioning means positions the frames in relation to each other vertically and horizontally. In the figures, the positioning means 8a-b is a pin and a hole.

The frames 5a-b comprise a first fixing means 9a-b for fixing the stator segments 3a-b to the frames 5a-b. The number of the first fixing means 9a-b is three in each frame in the figures. The number of the first fixing means 9a-b can be greater than three depending on the size of the permanent magnet machine 2. The frames 5a-b comprise second fixing means lOa-b for fixing the rotor segments 4a-b to the frames 5a-b. The number of the second fixing means lOa-b is three in each frame in the figures. The number of the second fixing means lOa-b can be greater than three depending on the size of the permanent magnet machine 2. The stator segments 3a-b and the rotor segments 4a-b are fixed to the frames 5a-b so that an axis of rotation 11 of the electrical machine 2 is substantially perpendicular to the platform 1.

The first elements 12a-b are fixed to the radially outer segments 4a-b and the second elements 13a-b are fixed to the frame 5a-b.

The platform 1 shown in the figures is suitable for an outer rotor electrical machine or an inner rotor electrical machine.

In an outer rotor electrical machine, the radially outer segments of the electrical machine 2 are rotor segments 4a-b. In an inner rotor electrical machine, the radially outer segments of the electrical machine 2 are stator segments 3a-c.

As the electrical machine 2 shown in all figures is an outer rotor electrical machine, the fixing means lOa-b, which comprises a first element 12a-b and a second element 13a-b, is numbered as the second fixing means lOa-b. The first elements 12a-b are fixed to rotor segments 4a-b, and the second elements 13a-b are fixed to the frames 5a-b. The linear movement direction is substantially perpendicular to the axis of rotation 1 1 of the electrical machine 2. The fixing means lOa-b comprising the first and second elements 12a-b, 13 a-b allows the radially outer segments 4a-b of the electrical machine 2 to move in relation to the frame 5a-b in a controlled way while being attached to the frame 5a-b.

The frames 5a-b shown in the figures comprise hollow section tubes. Examples of shapes of hollow section tubes are rectangular, square, tunnel, flat oval and elliptical oval tubes. Other materials can be used for the frames 5a-b as long as they are suitable for structural use. The frames 5a-b can also be made of plates with through-holes required for assembly and disassembly of the electrical machine 2. The advantage of a plate-line frame 5a-b is that it covers the winding ends and mechanically safeguards the air gap.

The platform 1 comprises two frames 5a-b in the figures. However, the number of frames can be higher, for instance, three or four. If the platform 1 comprises four frames 5 a-b, then the electrical machine 2 can be disassembled into four transportable units 28. A platform 1 comprising four frames 5 a-b can be obtained by dividing both frames 5 a-b shown in figures 1 and 2 into two in a lateral direction, for instance, and installing positioning means onto the new frame sides and installing attaching means for attaching the two new frames created from one frame together. A higher number of frames 5 a-b is advantageous when the electrical machine 2 to be disassembled is large or the transportation method from the factory to the site restricts the weight and size of a single disassembled unit. A platform 1 comprising four frames 5a-b allows the shape of a single frame 5a-b to be rectangular, a shape that utilizes the capacity of a container well. Figure 3 shows the linear movement directions of the first 12a-b and the second elements 13a-b. The number of the frames 5a-b forming the platform 1 is two. The first 12a-b and the second 13 a-b elements comprised in one frame 5 a-b move linearly towards the same direction. The number of radially r outer segments 4a-b is two. In the outer rotor electrical machine, the radially outer segments are rotor segments 4a-b. When the joints of the radial- ly r outer segments 4a-b are released, the number of parting surfaces 25a-b is two in each segment 4a-b. The first element 12a-b (dashed lines) and the second element 13a-b move linearly with respect to each other substantially in the direction of an angle bisector b _a _b of an angle of the radially r outer segments a. The angle a of a radially outer segment is formed between the parting surfaces 25a-b of the radially outer segment 4a-b. An angle bisector b _a _b divides the angle a into two angles of equal measures. With two radially outer segments 4a-b, which are to be divided into two, the angle a of one segment is 180°.

The number of radially outer segments 4a-b may be higher than the number of radially outer segments 4a-b to be released from each other. This means that some of the radially outer segments 4a-b remain interconnected. For instance, the number of radially outer segments can be four, and the number of radially outer segments to be released from each other is two. Then only some of the joints between the radially outer segments 4a-b are released. The angle a formed between the parting surfaces of the interconnected radially outer segments 4a-b is bigger than an angle a formed between the parting surfaces 25a-b of a single radially outer segment. The first elements 12a-b and second elements 13a-b allow the outer segments 4a-b to be moved by a linear movement in a length s from 4 cm to 40 cm. The required slit width between the outer segments 4a-b to be created by the linear movement of the outer segments 4a-b depends on the joint type of the inner segments 3a-c to be opened.

The length of the frame L corresponds to 100% to 120% of the diameter d of the radially outer segments 4a-b of the permanent magnet electrical machine 2.

The width of the frame w corresponds to 100% to 120% of the sum of half of the diameter d of the radially outer segments 4a-b of the permanent magnet electrical machine 2 and the distance s.

The first element 12a-b and the second element 13a-b are capable of providing linear movement with respect to the frames 5a-b. The first element 12a-b and the second element 13a-b comprise linear guides. A linear guide provides free motion in one dimension. Linear guides are moved by drive mechanisms, such as hydraulic cylinders.

If the first element 12a-b and the second element 13a-b are slideable with respect to each other, the first element 12a-b and the second element 13a-b are capable of carrying the ra- dial direction magnetic forces. Plain bearing linear guides have no moving parts and rely on low-friction sliding surfaces to move smoothly on their rails. Plain bearing linear guides, for example sliding contact bearings, are capable of providing linear movement by sliding with respect to the frames 5a-b. The advantage of the plain bearings is that they handle contamination well. As an example of the plain bearing linear guides, the first element 12a-b and the second element 13a-b comprise dovetail slides. The dovetail slides are shown in the figures. The dovetail slide is composed of a stationary linear base, i.e. the second element 13a-b, and a moving carriage, i.e. the first element 12a-b. Dovetail slides are advantageous when it comes to load capacity, affordability and durability. Another suitable linear guide type is a rolling element bearing linear guide. Relative linear motion between the guide components and their rails causes rotation in the intermediate rolling elements. The advantage of the rolling element linear motion guide is a lower friction motion than in the plain bearing linear guides. The rolling element bearing linear guide is composed of a stationary linear base, i.e. the second element 13a-b, and a moving carriage, i.e. the first element 12a-b.

Figures 4a)-b) show changes in the radial width of an air gap of the electrical machine. In the figures 4a)-b), only a half of the air gap of the electrical machine 2 resting on a frame 5a is shown. In figure 4a), the radial width of the air gap ai between the inner surface of the outer segments 4a and the outer surface of the inner segments 3a,c of the electrical ma- chine 2 is substantially fixed. The shape of the air gap ai is substantially uniform and the electrical machine 2 is ready for service.

Figure 4b) shows the radial width a of an air gap a ₂ , a ₃ between the stator segments 3a,c and the rotor segment 4a after the air gap width a ₂ , a ₃ has been changed by means of the first elements 12a and the second elements 13 a. The outer segment 4a is moved radially r outwards in the direction of an angle bisector b _a of an angle a of the outer segment 4a by means of the first elements 12a and the second elements 13a. The radial width of the air gap a ₂ , a ₃ is created to be non-uniform. The radial width of the air gap a ₂ , a ₃ between the inner surface of the radially outwards moved outer segment 4a and the outer surface of the inner segments 3a,c of the electrical machine 2 increases from the location of the parting surfaces 25a of the outer segments 4a towards the location of an angle bisector b _a of an angle a of the outer segment 4a. The maximum radial width of the air gap a ₂ is at the location of an angle bisector b _a of an angle a of one or more connected outer segments 4a. The minimum radial width of the air gap a ₃ is at the location of the parting surface 25a.

The created non-uniform radial width a of an air gap a ₂ , a ₃ between the stator segments 3a,c and the rotor segment 4a is kept during the transportation. The transportation of trans- portable parts 28 is shown in figure 9.

Figure 5 shows the transfer of a permanent magnet electrical machine 2 to the assembly and disassembly platform 1. The transfer of the permanent magnet machine 2 is made by lifting the electrical machine 2. The lifting is made with a crane (not shown) and ropes 16 using a lifting tool 17 attached to the electrical machine 2. The platform 1 comprises a track structure 18. The frames 5a-b can be moved on the track structure 18 into opposite directions. The frames 5a-b can be pulled together or pushed apart from each other on the track structure 18. The stoppers 19 of the track structure 18 limit the movement of the frames 5a-b. The track structure comprises rails 20 and the frames 5a-b comprise railway wheels 21 for moving the frames 5a-b on the track structure 18. The rails can be incorporated in the frames 5a-b and the railway wheels can be incorporated in the track structure 18 as well. In the factory assembly hall, the track structure 18 can rest on the floor, for example.

The permanent magnet electrical machine 2 comprises two rotor segments 4a-b and four stator segments 3a-c (not shown in Figure 3). The stator segments 3a-c and the rotor seg- ments 4a-d are fixed to the frames 5a-b so that an axis of rotation 11 of the electrical machine 2 is substantially perpendicular to the platform 1. The first end 22 of the electrical machine 2 faces the platform 1 and the second end 23 of the electrical machine 2 comprises the bearing unit 24.

The stator segments 3a-c are fixed to the frames 5a-b by means of the first fixing means 9a-b and the rotor segments 4a-b are fixed to the frames by means of the second fixing means lOa-b.

The radially outer segments are rotor segments 4a-b. The first element 12a-b is fixed to the radially outer segment 4a-b, and the second element 13a-b is fixed to the frame 5a-b. The first fixing means 9a-b is attached to the brake caliper mounts of the stator segment 3a-c, for example. After connecting the electrical machine 2 to the platform 1 from its stator segments 3a-c and rotor segments 4a-b, the electrical machine 2 is ready to be disassembled.

If the electrical machine on the platform 1 comprises a bearing unit 24, it is released from the electrical machine 2 and preferably lifted away. The bearing unit 24 can be transported separately to the site or attached later on to one of the transportable parts 28.

Figure 6 shows one joint 6a of the radially outer segments 4a-b and one joint 6b of the radially inner segments 3a-b of the electrical machine 2. The radially outer segments 4a-b are shown in a separated stage, i.e. the radially outer segments 4a-b are moved radially outwards. The radially inner segments 3a-b are shown in an interconnected stage. The joint 6a between the two adjacent radially outer segments 4a-b is released by opening the fastening means 32, for instance, a through-bolt coupling. The radially outer segments 4a-b are separated from each other by a separating means 26 shown in figure 7. The separating means 26 causes the outer segments 4a-b to move linearly apart by means of the first 12a-b and the second elements 13a-b. The first element 12a-b and the second element 13a-b are ca- pable of carrying the radial direction forces created by magnets when the joints 6a of the radially outer segments 4a-b are released. When the outer segments 4a-b are apart, they are fastened to the frame 5a-b. The outer segments 4a-b are fastened to frames 5a-b with a mechanical locking, for instance.

The joint 6b between the adjacent radially inner segments 3a-b is accessible through the slit created between the radially outer segments 4a-b. The joint 6b between the two adjacent radially inner segments 3a-b is released by opening the fastening means 32, for instance, a through-bolt coupling. The radially inner segments 3a-b are separated from each other by releasing the frames 5a-b from each other and moving the frames 5a-b apart by a disconnecting means 33. The separating means 26 is lead screws, ball screws, pneumatic or hydraulic cylinders, for instance. The disconnecting means 33 is lead screws, ball screws, pneumatic or hydraulic cylinders, for instance.

When the frames 5a-b are disengaged, the disassembly is made and the permanent magnet electrical machine 2 is in transportable parts 28. Figure 7 shows the radially outer segments 4a-b and the radially inner segments 3a-b in a separated stage. The separating means 26 and the disconnecting means 33 are comprised of hydraulic cylinders in the figure. The separating means 26 comprise several separate units. The units causing the linear movement of the outer segments 4a-b are attached to at least two first elements 12a-b in each frame 5a-b, whose elements 12a-b are located closest to the joints 6a of the outer segments 4a-b to be released, and to the outer segments 4a-b. The units attached to the outer segments 4a-b are located close to the joints 6a of the outer segments 4a-b to be released. The units are attached in an axial direction to the upper part of the outer segments 4a-b, whose upper part ends at the second end 23 of the electrical machine 2. The units of disconnecting means 33 causing the frames 5a-b to part are located on the joints of the frames 5a-b. The units of disconnecting means 33 comprise an attaching means 7 in the figure, but the attaching means 7 may also be an independent component.

Figure 8 shows a support structure 27 for a lightweight electrical machine. If the electrical machine 2 is designed as a lightweight electrical machine, a harmful deformation of the parting surface 25a-b may occur during the disassembly. A support structure 27 for rotor segments 4a-b and stator segments 3a-c can be used to prevent the harmful deformation of the parting surface 25a-b. A support structure 27 supports the radially outer segments 4a against magnetic forces acting in the air gap. The support structure 27 is installed on a non- divided electrical machine 2. The support structure is fixed to the radially outer segments, in figure 8 on the rotor segment 4a. The support structure 27 is fixed to the rotor segment 4a in the area where the rotor segment 4a is fixed to the frame 5a-b by means of a fixing means lOa-b. The support structure 27 is further fixed to the rotor segment 4a from the rotor outer surface in the direction of the shaft. This prevents the rotor segment 4a from de- forming in the area where magnetic forces try to bend the rotor segment 4a towards the stator segments 3a-c. In figure 8, the support structure 27 comprises a lower part 27a installed radially inside the radially outer segment 4a and a C-shaped upper part 27b. The parts are preferably integrated into one support structure 27 as shown in figure 8, but the lower part 27a and the upper part 27b can form two independent support structures. The support structure 27 is fixed to the rotor shaft side outer surface to improve its stiffness against forces created by the separating means 33. The support structure 27 is fixed to the radially outer segments 4a-b before releasing the joints 6a-b of the radially outer segments 4a-b in order to prevent the lateral buckling of the radially outer segments 4a-b during the separation of the radially outer segments 4a-b.

Figure 9 shows transportation with a truck 35. The permanent magnet electrical machine 2 is disassembled into transportable parts 28. The transportable part 28 of the electrical machine 2 rests on a frame 5a. The frame 5a is placed onto a means of transportation 35. The bearing unit 24 can be attached to the transportable part 28 or be transported as a separate part. During transportation, the transportable parts 28 are covered in order to avoid non- purities from entering the segments. The covering can be a truck container, a rail container or a sea container, for instance.

Figure 10 shows a permanent magnet electrical machine 2 on the assembly and disassembly platform 1 at a site. The frames 5a-b of the platform 1 are lifted to a track structure 18. The track structure 18 comprises adjustable legs 29 and adjusting means 30 for compensating the unevenness of the ground. The adjusting means 30 comprises a pneumatic or hy- draulic mechanism, for instance.

The frames 5a-b are pulled together with moving means 31. The frames 5a-b are attached together with attaching means 7. The joints 6b of the radially inner segments 3a-b are connected with fastening means 32 to interconnect the radially inner segments 3a-b. The uniting means 34 causes the outer segments 4a-b to move linearly together by means of the first 12a-b and the second elements 13a-b. The joints 6a of the radially outer segments 4a-b are connected to each other with fastening means 32. The fastening means 32 is a through- bolt coupling, for instance. The bearing unit 24 is transferred and connected to the electrical machine 2. The rotor segments 4a-b are released from the frames 5a-b by releasing the second fixing means lOa-b, and the stator segments 3a-c are released from the frames 5a-b by releasing the first fixing means 9a-b.

The moving means 31 and uniting means 34 comprise lead screws, ball screws, pneumatic or hydraulic cylinders, for instance.

Reference signs: 1 platform; 2 electrical machine; 3 stator; 3a-c stator segment; 4 rotor; 4a- b rotor segment; 5a-b frame; 6a-b joint; 7 attaching means; 8a-b positioning means; 9a-b first fixing means; lOa-b second fixing means; 11 axis of rotation; 12a-b first element; 13a- b second element; 14a-b side wall; 15a-b end wall; 16 rope; 17 lifting tool; 18 track structure; 19 stopper; 20 rail; 21 wheel; 22 first end; 23 second end; 24 bearing unit; 25a-b parting surface; 26 separating means; 27, 27a-b support structure; 28 transportable part; 29 leg; 30 adjusting means; 31 moving means; 32 fastening means; 33 disconnecting means; 34 uniting means; 35 truck; a angle of a segment; ai_ ₃ air gap width; b _a _ _b bisecting line; d diameter; L length; r radial direction; s distance; w width.