Abstract:
The present invention relates to a wind turbine having a generator with stator and rotor in a machine house that is disposed at the top of the wind turbine tower, wherein the stator has a support construction comprising a plurality of support arms. The generator of the wind turbine is a ring generator.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to a wind turbine having a generator with stator and rotor in a machine house that is disposed at the top of the wind turbine tower, wherein the stator has a support construction comprising a plurality of support arms. The generator of the wind turbine is a ring generator.  
         BACKGROUND OF THE INVENTION  
         [0002]    Wind turbines of this type are known and are already used in large numbers. The development of wind turbines is tending towards greater generator output. This trend is often accompanied by an increase in the dimensions of the separate components (especially their support arms) and hence their mass.  
           [0003]    Today&#39;s prior art, as shown in FIG. 1, has a wind turbine  1  whose nacelle  2  weight (machine house weight) is in the order of 90-100 tons. Part of this weight is that of the stator support  12  to which the stator  20  of the generator is mounted. Such prior art includes blades  3  coupled to a rotor  4 . The rotor  4  has connected thereto an electrical rotor system  5  for generating electricity in interaction with the stator  20  in a manner well known in the art. The wind turbine is thus composed of a relatively large mass. However, such large masses are difficult to handle and generate considerable stress on both the tower and the tower foundations, leading not only to increased material stress, but also to greater costs for the separate, aforementioned components of a wind turbine. Reference is made by way of illustration to the fact that the nacelles (that is, the machine house) of the wind turbine are not only transported to the erection site, but in many cases must be hoisted in their separate parts to the top of the tower.  
           [0004]    Another problem encountered with wind turbines relating above all, in addition to building law issues, to the acceptance of such turbines among the respective neighborhood, is that of noise emission, in that the noise emissions produced even by modern wind turbines constitute a disturbance and can therefore reduce the acceptance of such turbines.  
           [0005]    Part of the noise emissions are generated by the support arms, since these have a hollow interior and sealed outer surfaces, with the result that a resonant body is formed.  
         SUMMARY OF THE INVENTION  
         [0006]    One object of the present invention is therefore to specify a wind turbine whose components have reduced weight and whose noise emissions are lowered.  
           [0007]    This object is achieved in accordance with the invention by the stator support having an open structure. This open structure results in reduced weight, on the one hand, as well as less material being used, on the other. Noise emissions are also reduced, because by virtue of their open structure the support arms can no longer form a resonant body, thus eliminating the noise emission of the support arms, at least.  
           [0008]    Due to its lower weight compared to notorious designs, a stator support according to the invention thus helps to reduce the mass of the nacelle, and hence to improve handling and transportability of the components and/or the entire nacelle.  
           [0009]    Other preferred embodiments are characterized by the subclaims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    One embodiment shall now be described in detail with reference to the figures. These show:  
         [0011]    [0011]FIG. 1 shows the nacelle portion of a wind turbine  1  according to the prior art;  
         [0012]    [0012]FIG. 2 is a side elevation view of a support arm according to the invention; and  
         [0013]    [0013]FIG. 3 is a front view of a stator support according to the invention, with a plurality of support arms. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    The support arm  12  shown in a side elevation view in FIG. 2 has an open structure, with the result that it does not form a resonant body. Ascending from a base  18  of support arm, a plurality of holes  22  can be seen in support arm  12 , such that the structure of the support arm is formed by lateral bars  24  and traverse struts (traverses)  26  therebetween. Hence, support arm  12  does not constitute a resonant body and cannot, therefore, emit noise.  
         [0015]    The support arm  12  pursuant to the invention extends from base  18  along a predefined stretch that ensues from the size of the stator  20  attached to said support arm  12 . At the end of the support arm  12  opposite base  18 , a member  16  extends perpendicularly to support arm  12  and has a support plate  17  at the end of said member. A stator  20  is mounted on said support plate  17 . Stator windings  22  are inside the stator  20 . A rotor portion  5  is adjacent the stator. The support plate  17  may have a larger area than the cross-sectional area of member  16 .  
         [0016]    In the embodiment of support arm  12  according to the invention as shown in FIG. 2, the depth (i.e., the horizontal extension in the figure) is constant. Alternatively, however, said depth can vary and thus permit a change in the cross-section of the support arm  12  of the invention.  
         [0017]    [0017]FIG. 3 shows a plan view of a stator support  10  comprised of a plurality of support arms  12  pursuant to the invention. In the figure, one can well see the open, lattice-like structure of support arms  12  formed by bars  24  and traverse members  26 .  
         [0018]    Support arms  12  thus have an open structure and form, with their inwardly oriented bases  18 , an opening through which a rotor axis (a rotor spigot) can extend. Support arms  12  can be used as single elements in that regard. Alternatively, support arms  12  can be joined together, for example at their bases  18 , to form an integral stator support  10  or a plurality of stator support segments, which for their part can be deployed singly, or joined together to form an integral stator support  10 .  
         [0019]    The radially and outwardly directed end of each support arm  12  is divided into two extension arms  14 . The outer, perpendicularly angled member  16  of each extension arm  14  runs axially parallel to the direction of the rotor axis. The area of the support plate  17  to which the stator is attached is greater than the cross-sectional area of beam member  16 .  
         [0020]    The cross-section of extension arm  14  decreases in size from base  18  of the arm to its outer end, namely as it extends outward to the perpendicular member  16 . In the case of a support arm  12  as present in the embodiment shown here, this change in cross-section results, given that the depth (i.e., the horizontal extension of the support arms  12  in FIG. 2) remains constant, from the decreasing width (horizontal extension of the support arms  12  in FIG. 3), especially in extension arm  14 . Alternatively, the depth and width of support arm  12  and member  16  according to the invention may vary.  
         [0021]    In order to illustrate application of the invention, a portion of stator  20  is shown in its installed state, by way of example. Stator  20  extends in a ring shape over the entire outer periphery of the stator support  10  and is distanced from said stator support by the amount that support plate  17  is distanced from the extension arm  14  by member  16 . Substantial weight is therefore saved.  
         [0022]    In one embodiment of the invention, support arms  12  are attached either singly, as segments or as an integral stator support  10  to a sub-construction which for its part is firmly attached to the machine house.  
         [0023]    From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.