Abstract:
Embodiments of the invention relate generally to turbo-generators and, more particularly, to suspension systems for turbo-generators and the attenuation of vibration in a stator core induced by an electromagnetic load. In one embodiment, the invention provides a support clamp comprising: an arcuate body; a first affixation point; a second affixation point; and a securing point between the first and second affixation points, wherein each of the first and second affixation points includes a radially-oriented opening extending from an inner surface to an outer surface and the securing point includes an area adjacent to an angled opening extending from a first surface to a second surface, each of the first and second surfaces lying substantially perpendicular to the inner and outer surfaces of the arcuate body.

Description:
BACKGROUND 
     The stator cores of turbo-generators, e.g., electric power generators, experience vibration due to the electromagnetic load of the machine. Left unattenuated, this vibration is capable of causing fatigue in the stator core and frame, which can shorten its useful life. 
     Current attenuation systems include spring bars or similar devices affixed to the rigid stator frame structure surrounding the stator core. The components of such attenuation systems generally must be manufactured to small tolerances and are, therefore, relatively expensive to make, install, and service. 
     Applicants have found that attenuation equivalent or superior to that achievable using known attenuation systems may be achieved through the use of flexible wire members to attach the stator core to the surrounding rigid frame structure. The angling of wire members at various locations and at various angles between the stator core and the frame structure provides a tunable isolation system. In addition, wire members may be secured to the frame structure without the need for welding, reducing both construction time and material costs. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, the invention provides a suspension system for a turbo-generator core, the system comprising: a rigid stator frame structure comprising: a plurality of rigid ring members surrounding and axially disposed along a stator core; and at least one rigid anchor member affixed between a first and a second of the plurality of ring members; a plurality of key bar members extending from a first end of the stator frame to a second end of the stator frame; a plurality of support clamps, each support clamp comprising: an arcuate body; a first point affixed to a first of the plurality of key bar members; a second point affixed to a second of the plurality of key bar members; and a securing point between the first point and the second point; at least one tension member comprising: at least one elongate wire member having a first end and a second end; a first securing member at the first end of the elongate wire member, securing the first end of the elongate wire member to the securing point of one of the plurality of support clamps; and a second securing member along a length of the elongate wire member, securing the elongate member to the at least one anchor member of the stator frame. 
     In another embodiment, the invention provides a support clamp for a turbo-generator suspension system, the support clamp comprising: an arcuate body; a first affixation point; a second affixation point; and a securing point between the first and second affixation points, wherein each of the first and second affixation points includes a radially-oriented opening extending from an inner surface to an outer surface and the securing point includes an area adjacent to an angled opening extending from a first surface to a second surface, each of the first and second surfaces lying substantially perpendicular to the inner and outer surfaces of the arcuate body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which: 
         FIG. 1  shows a side view of a stator core and support system according to an embodiment of the invention. 
         FIG. 2  shows a perspective view of a support clamp according to an embodiment of the invention. 
         FIG. 3  shows a perspective view of a stator core and support system according to an embodiment of the invention. 
         FIG. 4  shows a perspective view of a tension member according to an embodiment of the invention. 
         FIG. 5  shows a perspective view of the tension member of  FIG. 4  secured to a stator frame structure. 
         FIG. 6  shows perspective views of an arcuate plate member according to an embodiment of the invention. 
         FIG. 7  shows a side view of the arcuate plate member of  FIG. 6  secured to key bar members and a stator core. 
         FIG. 8  shows a schematic cross-sectional view of a plurality of arcuate plate members in conjunction with a stator core according to an embodiment of the invention. 
         FIG. 9  shows a top perspective view of a suspension system having axial tension members according to an embodiment of the invention. 
     
    
    
     It is noted that the drawings of the invention are not to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements among the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings,  FIG. 1  shows a side view of a stator core  110  and support system  100  according to an embodiment of the invention. Support system  100  includes a plurality of key bar members  120 A,  120 B extending from a first end  110 A to a second end  110 B of stator core  110 . Affixed to key bar members  120 A and  120 B are a plurality of support clamps  130 A,  130 B, etc. 
       FIG. 2  shows a detailed perspective view of a support clamp  130  according to an embodiment of the invention. Support clamp  130  includes an arcuate body  132  having a first surface  132 A and a second surface  132 B, and from which laterally extend a first affixation point  134 , a second affixation point  136 , and a securing point  138  therebetween. First and second affixation points are affixed to key bar members  120 A and  120 B ( FIG. 1 ) using, for example, threaded members, welds, etc. One skilled in the art will recognize that any number of methods and techniques may be employed in affixing support clamp  130  to key bar members  120 A and  120 B, and will further recognize that such fixation may be permanent or non-permanent. For example, as shown in  FIG. 2 , support clamp  130  may be affixed to key bar members  120 A and  120 B by passing a threaded member, such as a bolt, through passages  135  and  137 , respectively, and securing the threaded member to key bar members  120 A and  120 B. 
     Support clamp  130  further includes a securing point  138 , shown in  FIG. 2  as a member extending laterally from arcuate body  132 . For the sake of simplicity in illustration, first and second affixation points  134 ,  136  and securing point  138  are shown only along one side of arcuate body  132 . One skilled in the art will recognize, of course, that similar features may be disposed along the side of arcuate body  132  obscured in  FIG. 2  and that such embodiments are intended to be within the scope of the invention. 
     Securing point  138  includes a passage  139  extending therethrough. As can be seen in  FIG. 2 , passage  139  of securing point  138  is oriented differently from passages  135  and  137  of first and second affixation points  134  and  136 , respectively. As will be explained in greater detail below, while passages  135  and  137  of first and second affixation points  134  and  136  are typically oriented substantially along an axis substantially perpendicular to a longitudinal axis of stator core  110  and the turbo-generator&#39;s rotor (not shown), securing point  138 , according to some embodiments of the invention, secures support clamp  130  (and stator core  110  to which it is affixed) to a rigid stator frame structure surrounding stator core  110  at an angle relative to an axis substantially perpendicular to a longitudinal axis of stator core  110  using one or more elongate, flexible wire members. As such, passage  139  of securing point  138  may be angled relative to an axis substantially perpendicular to a longitudinal axis of stator core  110 . 
     For example,  FIG. 3  shows a perspective view of stator core  110  surrounded by a rigid stator frame structure  140 . Stator frame structure  140  includes a plurality of rigid ring members  142 A,  142 B, etc. surrounding and axially disposed along stator core  110 . Stator frame structure  140  further includes at least one rigid anchor member  144  affixed between adjacent ring members  142 A,  142 B and oriented substantially parallel to a longitudinal axis of stator core  110 . 
       FIG. 4  shows a tension member  150  that may be used to secure stator core  110  to frame structure  140 . As shown in  FIG. 4 , tension member  150  includes an elongate wire member  152  having first and second securing members  154 ,  156  at either end. In some embodiments of the invention, wire member  152  comprises wire rope made up of a plurality of braided or twisted metal strands which may or may not surround a solid, braided, or twisted metal core. Non-metal materials, such as polyethylenes and nylons, may also be employed in some embodiments of the invention. Other materials are possible, of course, and the term “wire member,” as used herein, is intended to refer broadly to a flexible member. 
     As shown in  FIG. 4 , first securing member  154  comprises an “end button” or similar device to secure wire member  152  within a hole through which it is passed. That is, first securing member  154  has a diameter or dimension in at least one direction that is greater than wire member  152 , such that wire member  152  may be passed through a hole or passage but which is too small to allow first securing member  154  to pass. Any number of securing devices or methods may be so employed, as will be recognized by one skilled in the art. 
     For example, referring back to  FIG. 2 , wire member  152  may be passed through passage  139  of securing point  138  of support clamp  130 , such that first securing member  154  is held against securing point  138 , thereby securing tension member  150  to support clamp  130 . 
     Referring again to  FIG. 4 , second securing member  156 , located some distance from first securing member  154 , comprises a suspension anchor or similar device. Second securing member  156  acts similarly to first securing member  154  in securing wire member  152  within a hole through which it is passed. Second securing member  156  may comprise an anchor device, allowing pretensioning of wire member  152  using an external force, such as may be applied using a hydraulic pretensioner, and also maintain a high pretension on wire member  152 . As will become apparent from the further description provided below, second securing member  156  is preferably moveable along wire member  152 , such that, prior to attaching second securing member  156  to wire member  152 , wire member  152  may be passed through a hole in anchor member  144  ( FIG. 3 ) of stator frame structure  140  ( FIG. 3 ) and tension applied to wire member  152 . Upon attaching second securing member  156  to wire member  152 , such tension is maintained on wire member  152  as second securing member  156  is held against anchor member  144 , the diameter of which is greater than the hole in anchor member  144  through which wire member  152  is passed. Again, any number of securing devices or methods may be so employed, as will be recognized by one skilled in the art. 
     Second securing member  156  may include any apparatus or device and use any method to attach to wire member  152  including, for example, crimping, welding, bolting, the application of a compressive force, etc., as will be apparent to one skilled in the art. 
       FIG. 5  shows a perspective view of tension member  150  as secured to anchor member  144 , according to one embodiment of the invention. As can be seen in  FIG. 5 , wire member  152  has been passed through a hole (not shown) in anchor member  144 , with second securing member  156  attached to wire member  152  and held against anchor member  144 . In this way, the vibration caused by the electromagnetic load of stator core  110  may be transferred to stator frame structure  140 , and specifically to anchor member  144  of stator frame structure  140 , using tension member  150 , the first end of which (not shown) is secured to support clamp  130 , as described above. 
     Still referring to  FIG. 5 , suspension systems according to some embodiments of the invention may further include one or more cable compression bands  160  comprising an elongate wire member  162  disposed about a circumference of stator core  110  and secured to anchor member  144  in a manner similar to the securing of tension member  150 . Cable compression band  160  may, therefore, include a compression securing member  166  or similar device or apparatus. Cable compression band  160  acts to transfer at least a portion of the electromagnetic load of stator core  110  to stator frame structure  140 . In some embodiments of the invention, both ends of the portion of wire member  162  surrounding stator core  110  may be secured to the same anchor member  144 . In other embodiments, either end is secured to a different anchor member  144 . According to some embodiments of the invention, wire member  162  may be tensioned at the same end at which it is secured to anchor member  144  in order to maintain tension on wire member  162 . 
       FIG. 6  shows two perspective views of an arcuate plate member  170  for use in a support system according to one embodiment of the invention. Arcuate plate member  170  functions similarly to support clamp  130  ( FIG. 2 ) and comprises an arcuate body  172 , a first plurality of points  175  and a second plurality of points  177 , as well as a plurality of securing points  179  between the first and second plurality of points  175 ,  177 . Each of the first and second plurality of points  175 ,  177  and the plurality of securing points  179  includes a passage from an inner surface  171  to an outer surface  173  through body  172  of arcuate plate member  170 , analogous to passages  135 ,  137 ,  139  of support clamp  130 . The wider body  172  of arcuate plate member  170  affords a greater surface along which to secure a plurality of tension members  150  ( FIGS. 3-4 ) without changing the relative radial position of the point at which such tension members are secured. 
       FIG. 7  shows a plurality of arcuate plate members  170 A,  170 B,  170 C,  170 D affixed to key bar members  220 A and  220 B. Similar to support clamp  130 , arcuate plate members  170 A,  170 B,  170 C,  170 D are affixed to key bar members  220 A and  220 B at the first and second plurality of points  175 ,  177  using, for example, threaded members, welds, etc. As can be seen in  FIG. 7 , arcuate plate members  170 A and  170 D include downwardly-angled securing points, such that tension members  150 A and  150 D passing therethrough are angled downward, while arcuate plate members  170 B and  170 C include upwardly-angled securing points, such that tension members  150 B and  150 C passing therethrough are angled upward. 
     One skilled in the art will recognize that similarly-constructed arcuate plate members  170  may be employed to both downwardly and upwardly angle the respective tension members by simply changing the orientation of the arcuate plate members  170 . Similarly, arcuate plate members  170  may, according to some embodiments of the invention, include securing points  179  having differing (e.g., both upward and downward, differing upward, and/or differing downward) angles. 
       FIG. 8  shows a schematic cross-sectional view through a radial plane of stator core  110  according to one embodiment of the invention. As shown in  FIG. 8 , a plurality of arcuate plate members  170 A,  170 E are disposed about a circumference of stator core  110 . According to some embodiments of the invention, including that shown in  FIG. 8 , arcuate plate members  170 A,  170 E are disposed about the circumference of stator core  110  on a radial axis R and along a longitudinal axis (not shown) of stator core  110 . That is, arcuate plate members  170 A,  170 E are disposed at about the 9 o&#39;clock and about the 3 o&#39;clock positions, as seen through the radial plane of  FIG. 8 . Other circumferential positions for arcuate plate members may be employed, as will be recognized by one skilled in the art, those shown in  FIG. 8  being merely for purposes of illustration. 
     One or more tension members  150 A,  150 B,  150 E,  150 F extend laterally from arcuate plate members  170 A,  170 E, respectively. Tension members  150 B and  150 F are shown in phantom and are disposed outside the plane of tension members  150 A and  150 E. Tension members  150 B and  150 F may be secured to arcuate plate members  170 A and  170 E, respectively, or may be secured to arcuate plate members (not shown) adjacent arcuate plate members  170 A and  170 E, respectively, along a longitudinal axis of stator core  110 . 
     According to some embodiments of the invention, tension members  150 A,  150 B,  150 E,  150 F are angled with respect to radial axis R. As shown in  FIG. 8 , tension members  150 B and  150 F are angled upward from radial axis R at angle α 1 , while tension members  150 A and  150 E are angled downward from radial axis R at angle α 2 . According to some embodiments of the invention, angles α 1  and α 2  are, independently, between about 0° and about 90° with respect to radial axis R, e.g., between about 25° and about 75°, between about 45° and about 70°, about 70°, or about 65°. 
     One skilled in the art will recognize, of course, that the particular angle chosen for each of α 1  and α 2  will depend, for example, on the vibration caused by the electromagnetic load of stator core  110  to be transferred to stator frame structure  140  ( FIG. 3 ), the number and arrangement of support clamps  130  ( FIG. 2 ) and/or arcuate plate members  170 , the number and arrangement of tension members  150 , the composition of wire members  152  ( FIG. 4 ) of tension members  150 , etc. Applicants have found, in the applications in which embodiments of the invention have been employed and the degree of vibration attenuation measured, that angles of between about 0° and about 90° for each of α 1  and α 2 , e.g., between about 60° and about 75°, afford a degree of attenuation equal to or greater than that achievable using known attenuation methods. In other applications of the various embodiments of the invention, angles less than 60° and/or greater than 75° would be similarly efficacious. 
     In most applications in which embodiments of the invention may be employed, the greatest degree of vibration attenuation is achievable where the tension applied to each tension member  150  is substantially the same. 
     Support systems according to some embodiments of the invention may further comprise one or more axial tension members.  FIG. 9  shows a top perspective view of such axial tension members  158 A,  158 B,  158 C, etc. secured between a flange  112  or similar feature adjacent an end of stator core  110  and a rigid ring member  142 D of stator frame structure  140  ( FIG. 3 ). Axial tension members  158 A,  158 B,  158 C, etc. may be secured between flange  112  and rigid ring member  142 D in a manner similar to that described above with respect to the securing of tension member  150  ( FIG. 5 ) between anchor member  144  ( FIG. 5 ) and support clamp  130  ( FIG. 2 ). Axial tension members provide additional transfer of the electromagnetic load of stator core  110  to the stator frame structure  140 . 
     Applicants tested embodiments of the invention in various applications and found that, across a frequency range of 80 Hz to 140 Hz, vibrations in the stator core were attenuated to a degree equal to or greater than known suspension systems and methods. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any related or incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.