Abstract:
A generator rotor lead path configuration includes a plurality of electrically conductive components attached to each other. These components may include a cleat and a wedge. The improved lead path inhibits, if not prevents, lead path failure. A method of assembling or fitting the lead path into a generator is also provided, as well as a method of replacing or retrofitting a lead path that is susceptible to failure with the improved lead path configuration. Assistance in determining causes of lead path failure and ways to overcome lead path failure are also provided.

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to a lead path configuration for an electric device and, more particularly, to an improved lead path configuration for a generator rotor used in a power generation plant. 
     BACKGROUND OF THE INVENTION 
     Many power generation plants produce electricity by converting energy (e.g. fossil fuel, nuclear fusion, hydraulic head and geothermal heat) into mechanical energy (e.g. rotation of a turbine shaft), and then converting the mechanical energy into electrical energy (e.g. by the principles of electromagnetic induction). 
     Some of these power generation plants, such as a fossil-fuel power generation plant, comprise a turbine, a generator and an exciter. The turbine, generator and exciter are typically coupled to each other in axial alignment, with the generator located between the turbine and the exciter. 
     The turbine converts fossil fuel energy into mechanical energy in the form of turbine shaft rotation through a steam or combustion cycle. The generator then converts the rotational energy into electrical energy. The generator includes an axially extending rotor journaled in an annular stator that surrounds and sleeves the rotor. The rotor has a shaft in which conductive coil windings are axially arranged. The stator has punchings that collectively from an annular core in which conductive coil windings are positioned parallel with respect to the axial rotor coils. As the turbine shaft rotates the generator rotor, the exciter provides an electrical current to the rotor coil windings. The rotating electrically charged rotor creates a magnetic flux that induces an electrical current in the stationary stator coil windings. This induced electrical current is then drawn from the stator and constitutes the electricity that the power generation plant provides to electricity consumers. 
     One aspect of the above-described power generation scheme involves the electrical interconnection of the exciter and generator. An electrically conductive lead path is used to transport current in a closed loop configuration from the exciter, through the generator rotor coil windings, and then back to the exciter. It has been observed that, as a result of prolonged generator use, the lead path can physically sever or otherwise fail to properly carry current. Among other things, lead path failure can cause electric arcing or re-routing of the electric current through nearby conductive materials. Arcing and re-routing can, among other things, melt portions of the generator shaft and otherwise damage the generator. 
     It has also been observed that some portions of the lead path tend to fail more often than other portions of the lead path. In particular, it has been observed that lead path failure tends to occur along a portion of the lead path around area A shown in FIG.  2 . 
     There is thus a need for a lead path that inhibits, if not prevents, lead path failure. There is also a need for a portion of a lead path that is particularly suited to inhibit, if not prevent, lead path failure path around area A shown in FIG.  2 . There is further need for a lead path that improves upon the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention provides a lead path that inhibits, if not prevents, lead path failure, especially around area A shown in FIG.  2 . The present invention also provides a method of assembling or fitting the lead path of the present invention into a generator. The present invention further provides a method of repairing or retrofitting a lead path that has failed or is susceptible to failure with the lead path of the present invention. The present invention also recognizes that causes of lead path failure around area A shown in FIG. 2 are relatively unknown. Thus, the present invention also provides assistance in determining causes of lead path failure and identifies ways to overcome lead path failure. 
     One aspect of the present invention thus involves an apparatus adapted to form a conductive path for carrying an electric current in a generator having a shaft. The apparatus comprises an electrically conductive strap having a first end and a second end, and forming at least a portion of the conductive path. The apparatus also comprises a cleat having at least one axially extending spigot, the cleat adapted to retain the strap between the cleat and a portion of the shaft, the spigot sized and configured to carry at least a portion of a radial load of the strap and at least a portion of an axial load of the strap. 
     Another aspect of the present invention thus involves a method of retrofitting an electrical lead path in a generator. The method comprises removing a portion of a shaft of the generator to form at least one slot. The method also comprises arranging a conductive portion of the lead path between the shaft and a cleat, the cleat having a general T-shape with a portion that is sized and configured for placement within the at least one slot. The method also comprises attaching the cleat to the rotor so that the cleat can accept at least a portion of a radial load exerted by the strap and at least a portion of an axial load exerted by the strap. Yet another aspect of the present invention thus involves a method of choosing a plurality of electrically conductive components to inhibit electrical failure in a lead path of a generator. The method comprises identifying at least one phenomenon that may cause or tend to cause lead path failure. The method also comprises providing a plurality of components adapted to inhibit the identified at least one phenomenon from causing or tending to cause lead path failure, the plurality of components including a cleat component having at least one tapered spigot and adapted to secure a portion of the lead path and accept stress and load forces from the lead path during normal generator operation. The method also comprises arranging and attaching at least one electrically conductive component to form the lead path. 
     Further aspects, features and advantages of the present invention will become apparent from the drawings and detailed description of the preferred embodiment that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other concepts of the present invention will now be addressed with reference to the drawings of the preferred embodiment of the present invention. The illustrated embodiment is intended to illustrate, but not to limit the invention. The drawings contain the following figures, in which like numbers refer to like parts throughout the description and drawings and wherein: 
     FIG. 1 is a cutaway side elevation view of a generator in accordance with the present invention; 
     FIG. 2 is a cutaway side elevation view of a lead path that transports current from the exciter, through the generator rotor coil windings, and then back to the exciter; 
     FIG. 3 is a detail view of FIG. 2, showing a portion of the lead path; 
     FIG. 4 is a cut view of an existing rotor shaft taken along cut-line  4 — 4  in FIG. 3; 
     FIG. 5A is a perspective view of a cleat component of the present invention; 
     Fig. 5B is another perspective view of the cleat component of the present invention; 
     FIG. 6 is a perspective view of a wedge component of the present invention; and 
     FIG. 7 is a schematic view of a modified rotor shaft taken around cut line  4 — 4  in FIG. 3; and 
     FIG. 8 is a schematic view similar to the view of FIG. 7, showing a portion of the modified lead path that uses lead path components shown in FIGS.  5  and  6 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The generator rotor lead path configuration described herein employs several basic concepts. For example, one concept relates to a lead path that inhibits, if not prevents, failure during the lifetime of a generator that experiences normal use and routine maintenance. Another concept relates to a method of configuring and assembling a plurality of conductive components to form a lead path. Yet another concept relates to a method of retrofitting an existing generator to provide the generator with the lead path of the present invention. 
     The present embodiment of the invention is disclosed in context of use with a generator, for example, one having a similar design as a 2 pole hydrogen cooled, direct cooled rotor, with watercooled stator windings (“THDF”) generator that has been sold by the Siemens Corporation. The principles of the present invention, however, are not limited to THDF type generators. Instead, it will be understood by one skilled in the art, in light of the present disclosure, that the present invention disclosed herein can be successfully utilized in connection with other types of generators. One skilled in the art may also find additional applications for the lead path, components thereof, and methods disclosed herein, such as with other dynamoelectric machines, motors, wirings and apparatuses that use a conductive path. Thus, the illustration and description of the lead path of the present invention in connection with an exemplary generator is merely one possible application of the lead path of the present invention. 
     To assist in the description of the invention described herein, the following terms are used. “Inboard” and “outboard” are used to describe relative location, with “inboard” describing a location that is closer to the physical center of the generator rotor length than a location that is “outboard.” Thus, a component that has an “inboard end” and an “outboard end” can be understood to be arranged such that one end is closer to the physical center of the generator rotor length than the other end. 
     An overview of an exemplary existing generator and generator lead path is provided, followed by a more detailed explanation of the lead path of the present invention, to include various component parts and methods of use. Referring to FIGS. 1 and 2, a generator  10  is coupled in axial alignment between a turbine (not shown) and an exciter (not shown). The exciter provides an electrical current to the generator rotor. The current typically is a direct current. The current travels from the exciter in a closed loop configuration along a conductive lead path  18  that travels through the generator rotor  16  to the rotor coil windings  17 , and then back through another conductive lead path to the exciter. 
     An overview of an exemplary existing generator and generator lead path is provided, followed by a more detailed explanation of the lead path of the present invention, to include various component parts and methods of use. Referring to FIGS. 1 and 2, a generator  10  is coupled in axial alignment between a turbine (not shown) and an exciter (not shown). The exciter provides an electrical current to the generator rotor. The current typically is a direct current. The current travels from the exciter in a closed loop configuration along a conductive lead path  18  that travels through the generator rotor  16  to the rotor coil windings  17 , and then back through another conductive lead path to the exciter. 
     The lead path  18  commonly comprises a plurality of discrete interconnected conductive components, rather than a single unitary component. There are a variety of reasons why a plurality of components are advantageously used. For example, generator components near the lead path  18  often cause a portion of the lead path  18  to take on a particular size or shape. For another example, generator components near the lead path  18  often cause the lead path  18  to be attached to the generator in a particular manner. For yet another example, the lead path  18  often experiences varying stress and load forces. For an additional example, generator fabrication and maintenance efforts can be hindered if the lead path  18  comprises a single long unitary component. 
     FIGS. 2 and 3 show an exemplary existing lead path  18  comprising an axial lead  20  attached to a radial lead  22  and the radial lead  22 , in turn, attached to a J-strap  24 . The axial lead  20  physically and electrically connects with the exciter and the J-strap  24  physically and electrically connects with the coil windings  17 . As the J-strap extends outboard, it is restrained in the rotor  16  by several shaft wedges  44 . An end portion  26  of the J-strap  24  is freely suspended and centrifugally supported by a retaining ring  28  of the rotor  16 . The end portion  26  is axially positioned between the coil windings  17  and the rotor shaft  30 . Referring to FIG. 4, the rotor shaft  30  has a pair of ventilation scoops  32  positioned on opposing sides of a pole face centerline  34  (i.e. the portion of the rotor shaft  30  between the vent scoops  32 ), as well as a damper bar channel  36  holding a damper bar  38 . The vent scoops  32  provide egress for a cooling medium (e.g. air, hydrogen) that cools the rotor  16  during generator operation, and the damper bar  38  draws eddy currents from the rotor shaft  30  during generator operation  10 . 
     With the lead path  18  in this exemplary configuration, it has been observed that the lead path  18  tends to sever or otherwise fail near area A. It has been found that a variety of phenomenon may cause or tend to cause to the lead path to sever or otherwise fail near area A. One phenomenon involves radial expansion of the J-strap  24 , which may be caused by radial expansion of the retaining ring  28  during generator start up and operation. Since the J-strap  24  is supported by the radially expanded retaining ring  28 , the J-strap also radially expands. This radial expansion may cause or tend to cause various and varying stresses, and loads in or on the J-strap  24  or lead path  18 . Another phenomenon involves axial movement or pivoting of the J-strap  24 , which may be caused by thermal expansion of the coil windings  17  during generator start up and/or operation. Since the coil windings  17  have a higher thermal expansion rate than the rotor shaft  30  and are heated by the electric current, they axially expand faster and more than the rotor shaft  30  axially expands. This thermal expansion causes or tends to cause an outboard axial force on the J-strap  24 , which is positioned between the coil windings  17  and the rotor shaft  30  and must pivot from the curved bottom portion  29  of the J-strap  24  to allow for the thermal expansion. This axial expansion may cause or tend to cause various and varying stresses, stress concentrations, and loads in or on the J-strap  24  or lead path  18 . Moreover, the combination of the above-identified various and varying stresses, stress concentrations, loads and forces may exasperate lead path problems. These phenomenon may lead not only to J-strap  24  failure, but also to failure of the shaft wedges  44  or the rotor shaft  30 . Moreover, the combination of one or more of the above-identified phenomenon may exasperate lead path failure during generator startup and operation. 
     Components of the Present Invention 
     FIGS. 5 and 6 show various components of the lead path  18  of the present invention and are described below. These components include a cleat component  40  and a wedge component  42 . The present invention also advantageously uses a modified rotor shaft  43  (FIG.  7 ). The components are intended to address and withstand the varying and various stresses, stress concentrations, forces and loads that are exerted along the lead path  18 , especially around area A shown in FIG. 2, during normal generator operation in order to inhibit, if not, prevent lead path failure. 
     FIGS. 5A &amp; 5B show a cleat  40  of the present invention. The cleat  40  advantageously supports at least a portion of the radial load of the J-strap  24  during generator startup and operation, so that the radial load is no longer supported by the retaining ring  28 . The cleat  40 . also advantageously supports at least a portion of the axial load of the J-strap  24  during generator startup and operation, so that the axial load does not bend the J-strap  24 . In addition to supporting at least a portion of the radial and at least a portion of the axial J-strap  24  loads, the cleat  40  advantageously is configured to adapt or fit within the physical confines of the generator shaft  30  with little, preferably minimal physical modification to the generator  10 . 
     The illustrated cleat  40  has a generally T-shaped configuration with a first or radially inward end  46  and a second or radially outward end  48 , as well as a first or outboard face  50  and a second or inboard face  52 , although other geometries could be used (e.g. triangular-shaped, cross-shaped, diamond-shaped, polygonal-shaped, having a radial portion and an axial portion, curved, curvilinear, and the like). At least one spigot  54 , preferably a plurality of spigots and most preferably 2 spigots, extend from the cleat  40  to support at least a portion of the radial load of the J-strap  24  and the weight of the cleat  40 , and are adapted to be placed within spigot slot(s)  76  (described below). The exemplary embodiment shows two spigots  54  arranged on the radially inward end  48  of the inboard face  52  of the cleat  40 , toward opposing edges of the cleat  40 . An upper portion  56  of the spigot  54  is advantageously tapered  58  to assist in supporting the axial load of the J-strap  24 . The taper  58  has a constant angle of about 2° to about 60°, preferably about 10° to about 45°. There is no requirement, however, that the taper  58  be formed as a single portion on the spigot  54  or have a uniformly linear angle. Rather the taper  58  could be formed as a plurality of tapered portions and/or have one or more portions with a multilinear, curved or curvilinear composition. The spigots  54  have an axial length of about 0.1 inch to about 3 inches and preferably about 0.5 inch to about 1 inch, and a radial length of about 0.1 inch to about 3 inches and preferably about 0.5 inch to about 1 inch. 
     The illustrated cleat  40  also has at least one bolt-hole  60 , preferably a plurality of bolt-holes and most preferably 2 bolt-holes, arranged on the cleat  40  to provide a means for attaching the cleat  40  to the rotor shaft  30  (described below). The exemplary embodiment shows 2 bolt-holes  60  arranged on the radially inward end  46  of the cleat  40 , toward opposing edges of the cleat  40 . Each bolt-hole  60  has a circumference of about 0.1 inch to about 3 inches and preferably about 0.5 inches to about 1 inch, to allow a bolt to pass therethrough. If a plurality of bolt-holes  60  are used, they need not have the same diameter. 
     As will be understood by one skilled in the art, the cleat  40  can be configured in a variety of alternative ways. For example, instead of using at least one spigot  54  that extends away from the cleat  40 , a groove could be made into the other portions of the cleat  40 . For another example, other means for fastening the cleat  40  to the shaft  30  could be used, such as clamps, clips, adhesives, magnets, soldering, friction locks, brazing, other threaded or nonthreaded fasteners and the like. 
     The cleat  40  is constructed of a material having a suitable strength-to-weight ratio to withstand the varying and various stress, load and other forces supported by it during generator operation. Suitable materials include aluminum, titanium, magnesium, metal, alloys, fiberglass, composites and the like, as will be understood by one skilled in the art. 
     FIG. 6 shows a wedge component  42  of the present invention. The wedge  42  advantageously supports at least a portion of the radial load of the J-strap  24 , to include at least a portion of the upper or hammerhead portion  25  of the J-strap  24  (FIG.  8 ), during generator startup and operation, rather than this radial load being supported by the retaining ring  28 . In addition to supporting this radial load, the wedge  42  is advantageously configured to adapt or fit within the physical confines of the generator shaft  30  with little and preferably minimal physical modification to the generator  10 . 
     The illustrated wedge  42  has a generally trapezoidal shaped configuration with a first or radially inward end  62  and a second or radially outward end  64 , as well as a first and second sides  66 ,  68 , although other geometries could be used to achieve the purpose of the wedge (e.g. oval, lipped, ledged). The lower end  62  of the wedge  42  has a length of about 1 inch to about 6 inches and preferably about 2 inches to about 3 inches. The upper end  64  of the wedge  42  has a length of about 0.5 inch to about 4 inches and preferably about 1.5 inches to about 2 inches. The radial height of the wedge  42  is about 0.25 inch to about 6 inches and preferably about 0.5 inches to about 2 inches. The sides  66 ,  68  of the wedge  42  have a taper  70  with a constant angle of about 5° to about 85°, preferably about 15° to about 45°. There is no requirement, however, that the taper  70  have a uniformly linear angle, and could alternatively have a multilinear, curved or curvilinear composition. 
     The wedge  42  is advantageously constructed of a material having a suitable strength to withstand the varying and various stress, load and other forces supported by it during generator operation. In general, suitable wedge  42  materials are as strong as, if not stronger, than suitable cleat  40  materials, since the wedge  42  is relatively smaller than the cleat  40  and tends to have to withstand greater stresses, loads and other forces than the cleat  40 . Suitable materials include aluminum, titanium, magnesium, metal, alloys, fiberglass, composites and the like, as will be understood by one skilled in the art. 
     FIG. 7 shows a modified rotor shaft component  43  of the present invention. The modified rotor shaft  43  is advantageously modified by working a portion of the existing rotor shaft  30 . The shaft  43  can be modified by machining the rotor body face  72  of the existing rotor shaft  30  to form a J-strap slot  74 , at least one spigot slot  76 , and a hammerhead pocket  78 . The machining can be performed in any of a variety of ways, such by end milling the rotor body face  72 , or otherwise cutting, filing, sanding portions of the rotor body face  72  and the like. 
     The J-strap slot  74 , spigot slot(s)  76 , and hammerhead pocket  78  are advantageously configured to assist the cleat  40  and wedge  42  in supporting the radial and axial loads of the J-strap  24 . They are also advantageously configured to adapt or fit within the physical confines of the generator shaft  30  with little and preferably minimal physical modification to the existing generator  10  configuration. In particular, modification to the vent scoops  32 , damper bar channel  36  and damper bar  38  is desirably minimized so as not to retract from the functions of these elements and to reduce costs. One way to accomplish this is by configuring the J-strap slot  74 , spigot slot(s)  76 , and hammerhead pocket  78  substantially around, away from, or not on these elements. 
     The J-strap slot  74  is machined radially into the pole face centerline  34  between the vent scoops  32 . A thickness of about 0.1 inch to about 2 inches, and preferably about 0.5 inch and about 1.5 inch is left between the J-strap slot  74  and each of the vent scoops  32  for structural stability. This thickness may vary along the length of the J-strap slot  74  due to the varying thickness of the shaft  30  between the vent scoops  32 . The J-strap slot  74  is sized and configured to accept and retain a portion of the J-strap  24 , which can range from having a width of about 0.5 inches to about 5 and from having a depth of about 0.5 inches to about 4 inches. 
     The spigot slot(s)  76  are machined into the pole face centerline  34  between the vent scoops  32 . Although the illustrated embodiment shows the  2  spigot slots  76  directly connecting with the J-strap slot  74  and the vent scoops  32 , there is no requirement that they so connect. The spigot slots  76  are sized and configured to accept and retain the spigots  54  of the cleat  40  (described above). The spigot slots  76  have a corresponding taper  80  that cooperates with the taper  58  on the spigot  54  so that the spigots  54  can support at least a portion of the radial and axial loads of the J-strap  24  during generator start up and operation. 
     The hammerhead pocket  78  is machined into the pole face centerline  34  between the vent scoops  32 . A thickness of about 0.1 inch to about 2 inches, and preferably about 0.5 inch and about 1.5 inch is left between the hammerhead pocket  78  and each of the vent scoops  32  for structural stability. This thickness may vary along the length of the hammerhead pocket  78  due to the varying thickness of the shaft  30  between the vent scoops. The hammerhead pocket  78  is sized and configured to accept and retain the wedge  42  (described above), as well as at least a portion of the hammerhead  25  which can range from having a width of about 0.5 inches to about 5 and from having a depth of about 1 inches to about 8 inches. This hammerhead pocket  78  configuration, however, requires that the damper bar  38  be axially shortened about 1 to about 10 inches to provide a suitable space for the wedge  42  and/or hammerhead  25 . 
     The modified shaft  43  may also include one or more voids  82  that correspond with the one or more bolt-holes  60  in the cleat  40 . At least a portion of the voids  82  are threaded to secure a bolt (not shown). Advantageously, the inboard end  86  of the void  82  is threaded, since that end is father away from the curvature in the vent scoop  32  than the other end of the void  82 , which thus provides stronger structural support. The voids  82  have an axial depth of about 0.1 inch to. about 5 inches and preferably about 1 inches to about 2 inches. 
     The above-described components have been provided in terms of certain preferred and/or advantageous materials, dimensions, configurations, and connections (i.e. “specifications”). These specifications are provided with respect to the above-identified exemplary generator type. It will be understood by one skilled in the art that such disclosed specifications can be modified for use with other generators or apparatuses both presently known and later developed. It will also be understood by one skilled in the art that various specifications of one or more components can be interchanged and used with various specifications of one or more other components, consistent with the purposes of the present invention. It will be further understood by one skilled in the art that not all of the above-described components are required to provide the lead path of the present invention. For example, one or more components may be disregarded and other components modified or adapted to replace the disregarded component(s). 
     Assembly of the Present Invention 
     FIG. 8 shows an exemplary assembly of the lead path  18  of the present invention. For ease of explanation and understanding only, and in no way to limit the scope of the invention, the exemplary lead path  18  assembly is provided without every consideration that may be found if the lead path  18  is assembled within a previously assembled generator. 
     The rotor body face  72  of the existing rotor shaft  30  is worked as explained above. The inboard end  26  of the J-strap  24  is extended toward the rotor body face  72  of the modified rotor shaft  43 . At least a portion of the J-strap  24  is placed in the J-strap slot  74  and at least a portion of the hammerhead  25  is placed in the hammerhead pocket  78 . The inboard face  52  of the cleat  40  is placed against the J-strap  24 , with the tapered spigots  54  placed in the tapered spigot slots  76 . The cleat  40  is attached to the modified rotor shaft  43  by bolts (not shown) that extend through the bolt-holes  60  of the cleat  40  and into the threaded voids  82  in the modified shaft  43 . The wedge  42  is placed in the hammerhead pocket  78  above the hammerhead  25 . 
     One result of the above-described exemplary assembly of components is the advantageous ability to provide a J-strap  24  that is radially supported by the rotor shaft via the cleat  40  and wedge  42 , rather radially supported by the retaining ring  28 . Radially supporting the J-strap  24  via the retaining ring  28  places or transfers varying and various stresses, forces and loads onto the lead path  18 , and particularly onto the J-strap  24  portion of the lead path  18 . It is believed that such a transfer causes or tends to cause lead path  18  failure. Thus, by providing a J-strap  24  that is radially supported by the rotor shaft rather than the retaining ring  28 , a lesser amount of varying and various stresses, stress concentrations, forces and loads are transferred to the lead path  18 , and in particular to the J-strap  24 . 
     Another result of the above-described exemplary assembly of components is the advantageous ability to provide a lead path  18  that is axially supported by the rotor shaft via the cleat bolts  84  and the tapered spigot  54 . Unsuitable axial support places or transfers varying and various stresses, stress concentrations, forces and loads onto the lead path  18 , and particularly onto the J-strap  24  portions of the lead path  18 . It is believed that such a transfer causes or tends to cause lead path  18  failure. Thus, by providing a lead path that is suitably axially supported by the rotor shaft, a lesser amount of varying and various stresses, stress concentrations, forces and loads are transferred to the lead path  18 . 
     One way to provide a J-strap  24  that is radially and axially supported by the rotor shaft, is to place the J-strap  24  into a J-strap slot  74  and to place the hammerhead  25  into, a hammerhead pocket  78 . Then, secure the so-positioned J-strap  24  with the cleat  40 , wedge  42  and bolts. Such an arrangement and construction, among other things, allows at least a portion of the J-strap  24  to be radially supported by the tapered  58  spigot  54 , and at least a portion of the hammerhead  25  to be radially supported by the wedge  42 . Such an arrangement and construction, among other things, also allows the J-strap  24  to be axially supported by the tapered  58  spigot  54  and. bolts. 
     It will be understood by one skilled in the art that the present invention does not require that the above-described attachments be performed in any particular order, to include the above-described exemplary order. It will be also understood by one skilled in the art that the above-identified exemplary attachment techniques, as well as other attachment techniques known in the art, can be used to attach any one or more component to any other one or more component, and that any one or more component can be modified to use any one or more of these attachment techniques. It will be further understood by one skilled in the art that generator assembly or maintenance requirements may result in some or all of the above-described assembly steps to be interchanged, modified or even skipped. It will be still further understood by one skilled in the art that the disclosed components may be arranged in a variety of ways to provide a J-strap  24  that is radially and axially supported by the rotor shaft  30 . 
     It will also be understood by one skilled in the art that the lead path  18  of the present invention is advantageously symmetrical about the pole face centerline  34 , as well as symmetrical about each pole (e.g. within a 2 or 4 pole generator  10  configuration). A symmetrical design provides proper generator  10  balance. 
     Lead Path Retrofit 
     The above-described lead path components and assembly methods can also be used to retrofit an existing lead path of a generator. One way to perform such a retrofit is to place the J-strap  24  into a J-strap slot  74  that is machined into the existing shaft  30  and to place the hammerhead  25  into a hammerhead pocket  78  that is machined into the existing shaft  30 . Then, secure the so-positioned J-strap  24  with the cleat  40 , wedge  442  and bolts. 
     One result of the above-described exemplary retrofit is the advantageous ability to allow the J-strap  24  to be radially and axially supported by the rotor shaft. Not radially and axially supporting at least a portion of the J-strap  24  by the rotor shaft places or transfers varying and various stresses, forces and loads onto the lead path  18 , and particularly onto the J-strap  24  portions of the lead path  18 . It is believed that such a transfer causes or tends to cause lead path  18  failure. Thus, by providing a lead path  18 , and more particularly a J-strap  24  portion of the lead path  18 , that is radially and axially supported by the rotor shaft, a lesser amount of varying and various stresses, forces and loads are placed on the lead path  18 . 
     Although this invention has been described in terms of a certain exemplary uses, preferred embodiment, and possible modifications thereto, other uses, embodiments and possible modifications apparent to those of ordinary skill in the art are also within the spirit and scope of this invention. It is also understood that various aspects of one or more features of this invention can be used or interchanged with various aspects of one or more other features of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.