Abstract:
Embodiments of the invention relate generally to rotor installation systems and, more particularly, to permanent magnet rotor installation systems, including those having an in situ magnetizer or magnet insertion device. In one embodiment, the invention provides a rotor installation system comprising: at least one magnetizer for permanently magnetizing a ferromagnetic material; and an arbor for receiving a rotor having at least one portion including a ferromagnetic material, wherein the at least one magnetizer is positioned relative to the arbor to allow permanent magnetization of the ferromagnetic material.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Embodiments of the invention relate generally to rotor installation systems and, more particularly, to permanent magnet rotor installation systems, including those having an in situ magnetizer or magnet insertion device. 
         [0002]    The assembly of generators, motors, and other electrical machines containing permanent magnets requires special handling systems and safety precautions as the sizes and/or strengths of the magnets increase. That is, the large permanent magnets used in such machines exhibit magnetic forces and fields of such strength that their handling is hazardous to those involved in assembling the machines. The handling systems and safety precautions such assembly requires increase its cost and complexity. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    In one embodiment, the invention provides a rotor installation system comprising: at least one magnetizer for permanently magnetizing a ferromagnetic material; and an arbor for receiving a rotor having at least one portion including a ferromagnetic material, wherein the at least one magnetizer is positioned relative to the arbor to allow permanent magnetization of the ferromagnetic material. 
         [0004]    Another embodiment of the invention provides a rotor installation system comprising: an arbor for receiving a rotor; and a magnet insertion device for inserting into the rotor a plurality of permanent magnets. 
         [0005]    Still another embodiment of the invention provides a rotor installation system comprising: an arbor; an elongate member connected to the arbor and insertable inside a tubular member; and a welding device connected to the elongate member for forming at least one welded connection within the tubular member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    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: 
           [0007]      FIGS. 1-5  show a rotor installation system according to an embodiment of the invention; 
           [0008]      FIGS. 6A-6B  show a rotor installation system according to another embodiment of the invention; 
           [0009]      FIG. 7  shows a front view of a rotor; 
           [0010]      FIG. 8  shows a magnet insertion device used in another embodiment of the invention and adapted to insert one or more permanent magnets into the rotor of  FIG. 7 ; and 
           [0011]      FIGS. 9A-9D  show components of a rotor installation system according to yet another embodiment of the invention useful in forming welded connections between components of an electrical machine. 
       
    
    
       [0012]    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 between the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0013]      FIGS. 1-5  show an illustrative operational method of magnetizing and installing a rotor using a system according to one embodiment of the invention. Referring now to  FIG. 1 , a rotor installation system  1000  according to one embodiment of the invention is shown. The rotor installation system  1000  includes an arbor  1100  for receiving and securing a rotor, a magnetizer  1200  for magnetizing a ferromagnetic material within such a rotor, a support  1300  for a generator, motor, or similar device having a stator and into which the rotor will be installed, and a drive motor  1400  capable of rotating the rotor within the stator once installed. To facilitate installation of the rotor, the system  1000  further comprises rails  1110 A-B along which the arbor  1100  may move (i.e., along path A). Other components and/or modifications of the system  1000  will be known to one skilled in the art and are within the scope of the present invention. For example, the arbor  1100  itself or a portion thereof may be independently movable, obviating the need for the rails  1110 A-B. 
         [0014]    In  FIG. 2 , a rotor  2100  is shown being attached to the arbor  1100  and a motor  2200  having a stator being attached to the support  1300 . As can be seen, the rotor  2100  includes a plurality of ferromagnetic materials  2110 A,  2110 B . . .  2110   n  along its periphery. The ferromagnetic materials  2110 A- n  may include, for example, one or more of iron, nickel, cobalt, aluminum alloys of iron, aluminum alloys of nickel, aluminum alloys of cobalt, ceramic mixtures containing iron, ceramic mixtures containing nickel, ceramic mixtures containing cobalt, and neodymium-iron-boron alloys. These materials are provided merely for purposes of illustration and are not intended to be limiting. Other ferromagnetic materials will be known to those skilled in the art and are within the scope of the invention. 
         [0015]    In  FIG. 3 , a magnetic field  1210  is produced by the magnetizer  1200 , the magnetic field  1210  being of sufficient strength to impart to the ferromagnetic materials  2110 A- n  a degree of magnetism. For example, in the embodiment of  FIG. 3 , the arbor  1100  moves the rotor along path B (i.e., in a peripheral direction) to incrementally expose portions of the ferromagnetic materials  2110 A- n  to the magnetic field  1210 . That is, the arbor  1100  rotates the rotor  2100  through the magnetic field  1210  to magnetize the ferromagnetic materials  2110 A- n . In some embodiments, it may be desirable for the arbor  1100  to also be movable along path C (i.e., in a substantially vertical direction) to provide concentricity of the rotor  2100  during magnetization. Such movement along path C may also aid in installation of the rotor  2100  into a stator of the motor  2200 , as will be described below. 
         [0016]      FIG. 4  shows the rotor  2100 , with its ferromagnetic materials now magnetized, being installed into the stator of the motor  2200 . Such installation is accomplished, in the embodiment shown here, by moving the arbor  1100  along path A (i.e., in a substantially horizontal direction) using the rails  1110 A-B and, if necessary, along path C, in order to properly align the rotor  2100  and stator. Movement along either or both of paths A and C may be facilitated, for example, using hydraulic, pneumatic, electric, and/or other devices, as will be recognized by one skilled in the art. The particular mechanism(s) employed are not essential, of course, and any mechanism(s) facilitating movement along paths A and C (or any other paths described below) may be used. 
         [0017]    In  FIG. 5 , the rotor  2100  has been installed within the motor  2200 . The installation may be tested using the drive motor  1400  to rotate the rotor  2100  within the stator of the motor  2200  to determine, among other things, that the rotor  2100  is properly balanced. In some embodiments, the drive motor  1400  is a variable speed motor capable of rotating the rotor  2100  from a very low speed to an operational speed. 
         [0018]    Modifications to or variations of the system  1000  of  FIGS. 1-5  may be necessary or desirable, of course, depending on the size, type, etc. of the rotor, ferromagnetic material, stator, etc. For example, rotors having a more elongate shape than that shown in  FIGS. 1-5  may be more easily magnetized using a “pass-through” magnetizer that substantially surrounds all or a portion of such a rotor&#39;s periphery at various points along its axial length. Such an embodiment in shown in  FIGS. 6A-B . In  FIG. 6A , the rotor  2102  is again attached to the arbor  1112 , which is movable along paths A and C (i.e., in substantially horizontal and vertical directions). The magnetizer  1202 , however, is adapted to surround the rotor  2102  and, upon inducing a magnetic field, to magnetize the ferromagnetic materials (not shown) within the rotor  2102 . 
         [0019]      FIG. 6B  shows the arbor  1112  passing the rotor  2102  through the magnetizer  1202 . The magnetic field  1212  magnetizes the ferromagnetic materials, to yield a magnetized portion  2102 B of the rotor  2102 . An unmagnetized portion  2102 A of the rotor  2102 , which has yet to pass through the magnetizer  1202 , is incrementally passed through the magnetizer  1202  until the ferromagnetic materials of the entire rotor  2102  are magnetized. 
         [0020]    Embodiments having “pass-through” magnetizers, such as that shown in  FIGS. 6A-B , may be useful in magnetizing rotors for high-speed electrical machines (HSEMs), which, due to their high rotational speed and attendant high centrifugal forces, often employ a retaining ring or similar device for securing the ferromagnetic materials within the rotor. Imparting a desired degree of magnetism to the ferromagnetic materials therefore often requires a strong magnetic field. The production of such a strong magnetic field, as well as its uniform application to the rotor, is more easily accomplished using a “pass-through” magnetizer, such as that shown in  FIGS. 6A-B . 
         [0021]    In another aspect, the invention provides a rotor installation system having a magnet insertion device for inserting pre-magnetized ferromagnetic materials into a rotor. Thus, as with the rotor installation systems described above, such a system permits magnet insertion and rotor installation without exposure of assembly personnel to the strong magnetic forces and fields produced by large permanent magnets. 
         [0022]    For example,  FIG. 7  shows a front view of a rotor  2100  having a plurality of slots  2120 A,  2120 B . . .  2120   n  spaced around its periphery. Permanent magnets are inserted into the slots  2120 A- n , after which the rotor may be balanced and inserted into a stator of a generator, motor, or other electrical machine. 
         [0023]      FIG. 8  shows a magnet insertion device  3000  according to one embodiment of the invention. The magnet insertion device  3000  includes a body  3100  in which magnets may be contained, a plurality of passages  3110 ,  3112 ,  3114 ,  3116 , and rods  3200 A-B capable of passing through a passage (e.g.,  3114 ) to insert a magnet from within the body  3100  into a slot of the rotor. The passages  3110 - 3116  are shown angled with respect to the body, although this is not essential. In the illustrative embodiment shown in  FIG. 8 , magnet insertion is facilitated by the arbor (e.g.,  1100  in  FIG. 1 ) rotating the rotor  2100  with respect to the magnet insertion device  3000  until a rotor slot (e.g.,  2120 B) is aligned with a passage (e.g.,  3112 ) of the magnet insertion device  3000 . In other embodiments, the magnet insertion device  3000  may be rotated rather than, or in addition to, the rotor  2100 . A rod (e.g.,  3200 A) then passes through the passage  3112  (i.e., along path E) to insert a magnet into the slot  2120 B. The rod  3200 A is then withdrawn and the arbor  1100  rotates the rotor  2100  until an empty slot (e.g.,  2120 A) is aligned with a passage of the magnet insertion device  3000 . As noted above, hydraulic, pneumatic, electric and/or other devices and mechanisms may be employed in rotating the rotor  2100  and/or moving the rod  3200 A-B along path E. Once magnets are inserted into each of the slots  2120 A- n , the rotor may be balanced and inserted into a stator, as described above with respect to  FIGS. 4-5 . 
         [0024]    In yet another aspect, the invention provides a rotor installation system having a welding apparatus for forming welded connections in rotors and the electrical machines into which the rotors are installed.  FIGS. 9A-D  show one embodiment of such a system and its application. In  FIG. 9A , the rotor installation system  4000  is shown. As in the systems described above, the system  4000  includes an arbor  1114  movable along paths A, B, and C. To the arbor  1114  is connected a welding system  1500  comprising an elongate member  1510  and a welding device  1530 . In some embodiments, the welding device  1530  is movable about a circumference of the elongate member  1510  (i.e., along path F). The welding device  1530  itself includes, in some embodiments, a rotary unit  1532  for moving the welding device  1530  about the circumference of the elongate member  1510  and a welding torch  1534  for forming the welded connections. Welding devices suitable for use in such an embodiment of the invention include, for example, those available from Magnatech LLC (East Granby, Conn.), including their orbital weld heads, such as the D Weld Head model  420 . Use of such devices may require, for example, reorientation of the welding torch  1534  to face outward from rather than inward toward the elongate member  1510 . Such devices often include the ability to include a video camera, which may be useful, in some embodiments, for inspecting the welded connections made. 
         [0025]      FIG. 9B  shows a cross-sectional view of the type of rotor or electrical machine component  2400  to which the system  4000  may be applied. Here, the component  2400  comprises a tubular member  2410  and a bellows  2420 . In this example, the bellows  2420  are to be secured to the tubular member  2410  via a welded connection on an interior of the tubular member. Other types of components and types of welded connections are also amenable to the system  4000  and are within the scope of the invention. The example given here is merely for purposes of illustration. 
         [0026]    In  FIG. 9C , the welding system  1500  has been inserted into the tubular member  2410  such that the welding torch  1534  is positioned to form a first weld Wi on an inner surface of the tubular member  2410 . The welding system  1500  and/or the welding device  1530  may then be rotated along paths B and/or F, respectively to extend the first weld W 1  and/or form additional welds along the inner surface of the tubular member  2410 . In  FIG. 9D , the welding system  1500  has been so rotated along path B to form a subsequent weld W n . 
         [0027]    The welding system  1500  described above may be used, for example, to form welded connections between components of a rotor, between components of a rotor and stator, or between any components of an electrical machine. The description above is given merely for purposes of illustration. 
         [0028]    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.