Abstract:
A magnetically levitated transport system moves a suspended cargo such as passengers and freight. A linear motor uses a track stator about which a “rotor” moves linearly. Stator and rotor circuits interact electromagnetically to maintain a gap between the moving and fixed elements. Tractor coils are embedded within the track to produce thrust through electromotor action with magnets aboard the rotor. The rotor is configured in a triangular shape as is the track with opposing electromagnets positioned for creating mutual repulsion forces. A pulsed direct current in the stator circuit, derived from conventional alternating current taken from the power grid, is used to create an induced current in the rotor, which, in turn is used to energize rotor electromagnets.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part application of U.S. patent application Ser. No. 11/209,916 filed Aug. 22, 2005 now abandoned, which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTTED ON A COMPACT DISC 
     Not applicable. 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable. 
     SEQUENCE LISTING 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Present Disclosure 
     This disclosure relates generally to electric motor-generators and more particularly to to a DC linear electromagnetic machine operating by electrical induction. 
     2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
     Tu et al, US 2004/0135452, discloses a flat rotary electric generator that includes at least one toroidal coil structure for cutting magnetic lines to induce a current and at least one disc-shaped magnetic pole structure oriented parallel to the helical coil structure. If multiple toroidal coil structures and disc-shaped magnetic coil structures are included, the toroidal coil structures and disc-shaped magnetic coil structures are arranged in alternating manner. The toroidal coil structure and disc-shaped magnetic pole structure are not provided with a permeable material. When either the toroidal coil structures or the at least one disc-shaped magnetic pole structure is rotated by an external force, the toroidal coil structure cuts the magnetic lines passing therethrough to generate an induced current. Neal, US 2002/0135263, discloses a plurality of stator arc segments that form a toroidal core for a stator assembly used to make a motor. In a preferred embodiment, a plurality of magnetic fields is created when electrical current is conducted through wire wound around poles on the toroidal core. A monolithic body of phase change material substantially encapsulates the conductors and holds the stator arc segments in contact with each other in the toroidal core. Hard disc drives using the motor, and methods of constructing the motor and hard disc drives are also disclosed. Rose, U.S. Pat. No. 6,803,691, discloses an electrical machine that comprises a magnetically permeable ring-shaped core centered on an axis of rotation and having two axially-opposite sides. Coils are wound toroidally about the core and disposed sequentially along the circumferential direction. Each coil includes two side legs extending radially alongside respectively sides of the core. Coil-free spaces exist between adjacent side legs. A bracket has first and second side flanges that are connected by a bridging structure and respectively abut the first and second sides of the coil. Mohler, U.S. Pat. No. 6,507,257, discloses a bi-directional latching actuator that is comprised of an output shaft with one or more rotors fixedly mounted thereon. The shaft and rotor are mounted for rotation in a magnetically conductive housing having a cylindrical coil mounted therein and is closed by conductive end caps. The end caps have stator pole pieces mounted thereon. In one embodiment, the rotor has at least two oppositely magnetized permanent magnets which are asymmetrically mounted, i.e., they are adjacent at one side and separated by a non-magnetic void on the other side. The stator pole piece has asymmetric flux conductivity and in one embodiment is axially thicker than the remaining portion of the pole piece. An abutment prevents the rotor from swinging to the neutral position (where the rotor magnets are axially aligned with the higher conductivity portion of the pole piece). Thus, the rotor is magnetically latched in one of two positions being drawn towards the neutral position. Energization of the coil with an opposite polarity current causes the rotor to rotate towards its opposite latching position whereupon it is magnetically latched in that position. Mohler, U.S. Pat. No. 5,337,030, discloses a permanent magnet brushless torque actuator that is comprised of an electromagnetic core capable of generating an elongated toroidally shaped magnet flux field when energized. Outside the generally cylindrical coil is an outer housing with upper and lower end plates at each end. Mounted to the end plates and extending towards each other are stator pole pieces separated from its opposing pole piece by an air gap. A permanent magnet rotor is disposed in the air gap and mounted on a shaft which in turn is rotatably mounted in each of the end plates. The permanent magnet rotor comprises at least two permanent magnets, each covering an arcuate portion of the rotor and having opposite polarities. Energization of the coil with current in one direction magnetizes the pole pieces such that each of the two pole pieces attracts one of the magnets of the rotor and repels the other magnet of the rotor resulting in a torque generated by the output shaft. Reversal of the current flow results in a reversal of the torque and rotation of the rotor in the opposite direction. Preferred embodiments are disclosed having multiple cells, i.e. a plurality of stator rotor stator combinations and/or cells in which there are a plurality of pole pieces at each stator pole plane. Kloosterhouse et al, U.S. Pat. No. 5,191,255, discloses an electromagnetic motor that includes a rotor having a plurality of magnets mounted along a perimeter of the rotor. Preferably, adjacent magnets have opposite poles facing outward. One or more electromagnets are disposed adjacent to the perimeter of the rotor so that as the rotor rotates, the magnets mounted on the rotor are carried near the poles of the electromagnets. Current is supplied to the electromagnets by a drive circuit in a predetermined phase relationship with the rotation of the rotor such that, for substantially all angular positions of the rotor, magnetic attraction and repulsion between the poles of the electromagnets and the magnets mounted on the rotor urge the rotor to rotate in a desired direction. Reflective material is mounted on the rotor in predetermined angular positions. The drive circuit includes a photosensitive device which produces a signal whose value varies according to whether the device is receiving light reflected from the reflective material. The signal is amplified to produce drive current for the electromagnets. Westley, U.S. Pat. No. 4,623,809, discloses a stepper motor housing a pole structure in which a pair of identical stator plates, each having a plurality of poles, are positioned back to back with the poles projecting in opposite directions, the stator plates being positioned between a pair of substantially identical stator cups, each stator cup having a plurality of poles projecting inwardly from a back wall with a peripheral side wall terminating in an outwardly extending flange. A major surface of each flange is in contact with a face on one of the stator plates so as to assure a low reluctance magnetic path. Fawzy, U.S. Pat. No. 4,565,938, discloses an electromechanical device which can be used as a motor or as a generator. The device has a housing, including bearing means to support a rotatable shaft. Disc magnet means are provided, and poled to have alternating polarity and are mounted on the shaft to define a rotor. The device includes at least one first pole shoe in contact with the magnet means, having a portion extending radially therefrom to define a virtual pole chamber, of a first polarity. Also included is at least one second pole shoe in contact with the magnet and having a portion extending radially therefrom to define a virtual pole chamber of the other polarity. A toroid stator is mounted on the housing and has windings thereon. The stator is positioned annularly around the disc magnets such that the virtual pole chambers of the first and second pole shoes surround portions of said windings with circumferentially alternating fields of alternating polarity. Means are provided for electrical contact with the stator to draw off current when the device is operated as a generator, or provide current to operate the device as a motor. Fawzy, U.S. Pat. No. 4,459,501, discloses an electromechanical device which can be used as a motor or as a generator that has a housing, including bearing means to support a rotatable shaft. A pair of disc magnets are poled to have opposite polarity on the two faces of each. The magnets are mounted face to face together on the shaft to define a rotor. The device includes at least one first pole shoe in contact with one face of each magnet, and having a portion extending radially therefrom to define, in its preferred form, a pair of virtual pole chambers, of the same polarity as said one face. Also included is at least one second pole shoe in contact with the other face of each magnet and having a portion extending radially therefrom to define in its preferred form a pair of virtual pole chambers of the same polarity as the other face. A toroidal stator is mounted on the housing and has windings thereon. The stator is positioned annularly around the disc magnets such that the virtual pole chambers of the first and second pole shoes surround portions of said windings with circumferentially alternating fields of alternating polarity. Means for electrical contact with the stator draw off current when the device is operated as a generator, or provide current to operate the device as a motor. 
     The related art described above teaches linear motors and their uses. Such motors have been contemplated for use in transport systems. However, the prior art fails to disclose a transport system as defined in the detailed description and accompanying drawings. The present disclosure distinguishes over the prior art providing heretofore unknown advantages as described in the following summary. 
     BRIEF SUMMARY OF THE INVENTION 
     This disclosure teaches certain benefits in construction and use which give rise to the objectives described below. 
     The present invention is a magnetically levitated transport system for moving a suspended cargo such as passengers and freight. A linear motor uses a track stator about which a “rotor” moves linearly. Stator and rotor circuits interact electromagnetically to maintain a gap between the moving and fixed elements. Tractor coils are embedded within the track to produce thrust through electromotor action with magnets aboard the rotor. The rotor is configured in a triangular shape as is the track with opposing electromagnets positioned for creating mutual repulsion forces. A pulsed direct current in the stator circuit, derived from conventional alternating current taken from the power grid, is used to create an induced current in the rotor, which, in turn is used to energize rotor electromagnets. 
     A primary objective inherent in the above described apparatus and method of use is to provide advantages not taught by the prior art. 
     Another objective is to provide an electromagnetic linear machine which develops a linear propulsive force and levitation using electromagnetic induction. 
     A further objective is to provide such a machine useful as a transport system. 
     A further objective is to provide such a machine capable of recovering electrical energy upon braking. 
     A further objective is to provide such a machine capable of maintaining a desirable vehicle orientation about an axis in the direction of propulsion regardless of load imbalance or centripetal force vectors. 
     A further objective is to provide a linear operating machine capable of developing propulsion and braking forces without direct physical contact with an electrical current supply. 
     A further objective is to provide such a machine that is operated using energy supplied from an on-board power supply or an external power feed, or a combination of both. 
     Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the presently described apparatus and method of its use. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Illustrated in the accompanying drawing(s) is at least one of the best mode embodiments of the present invention In such drawing(s): 
         FIG. 1  is a conceptual diagram of the presently described apparatus shown as a frontal elevational sectional view; 
         FIG. 2  is a vertical cross-sectional view of a linear motor thereof; 
         FIG. 3  is an electrical schematic diagram of a stator portion of the linear motor showing a preferred arrangement of traction windings thereof; 
         FIG. 4  is an electrical schematic diagram of the stator portion of the linear motor showing a preferred arrangement of levitation and stability solenoids thereof; 
         FIG. 5  is an electrical schematic diagram of the rotor portion of the linear motor showing a preferred arrangement of levitation, stability and traction solenoids thereof; 
         FIG. 6  is a conceptual perspective view of a length of the stator showing major elements thereof; 
         FIG. 7  is a table of symbols and their explanation used in  FIGS. 8-10 ; 
         FIG. 8  is a side elevational view of the stator and its structural support shown with the symbols of  FIG. 7 ; 
         FIG. 9  is an electrical schematic shown as a vertical sectional view of the linear motor similar to  FIG. 2  using the symbols of  FIG. 7 ; and 
         FIG. 10  is a side elevational view of the linear motor shown with a gondola of the invention using the symbols of  FIG. 7  to illustrate the electrical interactions of stator and motor. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The above described drawing figures illustrate the present invention and its method of use in at least one of its preferred embodiments, which is further defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications to what is described herein without departing from its spirit and scope. Therefore, it must be understood that what is illustrated is set forth only for the purposes of example and that it should not be taken as a limitation in the scope of the present apparatus and method of use. 
     Described now in detail is a magnetically levitated transport system  10 . As shown in  FIG. 1 , the system comprises a plurality of rigid structural supports  20 , an extensive linear track (also stator)  30 , a rotor  40 , and a gondola  50 . The stator  30  and rotor  40  comprise a linear motor. The term “rotor” is used herein to refer to the moving member of the linear motor although it does not rotate, but rather moves linearly along the track  30 . The supports  20  are spaced apart and secured at their respective lower ends to a surface  5  which is preferably similar to a typical railroad right-of-way, i.e., a stable and compact supporting surface. The track  30  is rigidly mounted to the lower ends of hangers  100  which depend downwardly from the supports  20  and which may be formed integrally with the track  30  as shown in  FIG. 1 . The term “track” is loosely applied to the non-moving member (stator) of the linear motor in that the present apparatus is designed to interface the rotor  40  only electromagnetically with track  30 , and without physical contact except in an emergency. The rotor  40  is normally electromagnetically engaged with track  30 , and is propelled along it by electromotive forces carrying its downwardly depending gondola  50  in a manner that is described in detail herein. Because there is normally no physical contact between rotor  40  and stator  30 , no rotating wheels, and no friction forces, the rotor may achieve relatively high velocity in moving along track  30 . Potentially, only the airodynamic drag forces developed in the spaces between rotor  40  and stator  30  are limiting. 
     The word “magnet(s)” is used herein to refer to, and alternatively has the meaning of (i) a simple permanent magnet(s), (ii) an electromagnet(s) with a permeable iron core (solenoid), and (iii) an electromagnet(s) with a permanent magnet core. Likewise, the term “magnetic” shall mean also “electromagnetic” herein. 
       FIG. 2  is a mechanical schematic diagram showing graphically, but not necessarly in true proportion, a typical vertical cross-section of the track  30  as engaged with the rotor  40  and which together takes the general shape of a triangle with sides “A,” “B” and “C” as illustrated. The letters “A,” “B” and “C” are used with reference numbers in the notation to identify which of the three sides a specific element is position on. For instance “ 220 A” and “ 220 B” are identical elements located on the A side and the B side respectively. When no letter is shown, for example, “ 220 ”, the reference is to all elements  220 . 
     Referring further to  FIG. 2 , magnetic forces are used to maintain physical separation between track  30  and rotor  40 , wherein, as part of the track  30 , first magnet pairs  110  and  210  mutually repel each other, and second magnet pairs  130  and  230  also repel each other. Both the first and second magnet pairs assure lateral, or side-to-side separation between track  30  and rotor  40  during operation. Also, third magnet pairs  130  and  225  as well as fourth magnet pairs  130  and  235  provide mutual repulsion, and are positioned to assure vertical separation between track  30  and rotor  40  during operation. With all four of the aforsaid magnet pairs active, it is clear that the rotor  40  is able to maintain its spaced apart position relative to track  30 , as the rotor moves along track  30 . To accomplish this, the magnets  110  and  130  extend “continuously” along track  30  as shown conceptually in  FIG. 6 . In practice, magnets  110  and  130  preferably comprise a linear series of spaced apart individual magnets as shown in  FIG. 4 . Individual electrical control of the polarities of the magnet sets shown in  FIG. 4  is necessary as will be explained below. 
     Magnets  220  which are mounted on rotor  40  are in positions that are aligned with slots  122  of sheet  120  ( FIG. 6 ) an electrically permeable material. Tractor coils  106  ( FIG. 3 ) are wound within slots  122 . Sheets  120  are mounted in axial orientation along each side A, B and C of the track  30 . Slots  122  may be rectangular or circular and are C-shaped in cross section with the opening facing outwardly toward rotor  40 . Slots  122  are, as shown in  FIG. 6  spaced apart along track  30  preferably in a uniformly repeating sequence but will necessarily be spaced closer on up-hill draws, and further apart on a down-grade. In their separate locations along track  30 , each set of interconnected three tractor coils  106 A,  106 B and  106 C are aligned in a vertical plane orthogonal to track  30  so that they interact electromagnetically with respective magnets  220  simultaneously as magnets  220  move past. 
     The magnets  110 ,  130 ,  210 ,  220 ,  225 ,  230 , and  235  are perferably made up of a linear series of smaller magnets positioned in a side-by-side relationship and in one embodiment of the present invention where they are configured as electromagnets they may be wired in electrical series or in electrical parallel or series-parallel arrangements. Just as magnets  110  and  130  are fixedly mounted on track  30  extending axially, as previously described, magnets  210 ,  220 ,  225 , and  235  are fixedly mounted on rotor  40  and also extend axially as linear arrangements of spaced apart individual magnets. 
     As with most mass-transit systems, the present invention may include one or more separate, or separatable cargo carrying cars or, as previously defined, gondolas  50 . When more than one such gondola  50  is strung together to form a train, each gondola  50  will be engaged with one or more rotors  40 , so that multiple rotors  40  will travel along stator  30  which acts as a conventional train track in supporting and directing the train, but also acts as an active electromagnetic component in propelling it. 
     As shown in  FIG. 3 , an electrical schematic diagram of the tractor or propulsion elements of the track  30 , electrical power is provided to the present apparatus generally as 60 Hz., three-phase, alternating current (AC). This AC is provided from existing power utilities found along the right of way, and may be carried in separate conduits (not shown) strung between and along the standoffs  20 . At spaced apart locations, possibly miles apart, rectifiers  108 , mounted on selected standoffs  20 , receive the AC and provide full-wave rectification, referred to herein as pulsed DC (PDC), which is delivered to power lines  107  which are carried along track  30  from hanger  100  to hanger  100  (see  FIG. 1 ). 
     PDC is taken off lines  107 , as shown in  FIG. 3 , by tractor cables  106 ′ and delivered to circuits  105  where hall sensors of circuits  105  direct switches of circuits  105  to establish the PDC as either a positive or a negative polarity with respect to a neutral or ground voltage reference. Circuits  105  are mounted on track  30  ( FIG. 2 ); wherein PDC is delivered to the tractor coils  106  embedded in track  30  and routed through the slots  122  in the permeable material  120 . 
     As shown in  FIG. 5 , preferably each set of magnets  210 ,  220 ,  225 ,  230  and  235  of rotor  40  may be configured as electromagnets. Because PDC carries a transient alternating current component, the transformer effect induces and AC current in the circuit of  FIG. 5  and such induced current is rectified to a DC current in rectifier  260  and then stored in battery  250 . Battery  250  is therefore always fully charged and provides a DC magnetization current to the magnets of rotor  40 . As a backup source of power to the magnets of rotor  40 , gasoline powered electrical generator is carried by rotor  40  and connected into the circuit of  FIG. 5  when switch S 1  closed. 
     The elements in  FIGS. 3 and 5  are shown arranged in electrical series, however, those of skill in the art could arrange the elements in an electrical parallel circuit, or in a series-parallel circuit. 
     In an alternate embodiment, the electro-magnets  210 ,  220 ,  225 ,  230 ,  235  may be configured, as previously described, as simple permanent magnets. Operation of the invention is carried out in a similar manner as described above with the permanent magnets responding to the electromagnetic forces produced in the circuits of  FIGS. 3 and 4 . 
     The loading of gondola  50 , and the dynamic inertial forces experienced by the rotor  40  during accelerations and on turns, may be best accommodated by the dynamic adjustment of magnetization current flow in the several magnet pairs which are used, as described above, for maintaining clearance gap between stator  30  and rotor  40 . To accomplish this dynamic adjustment, proximity sensors  106  are used to sense the instantaneous gap in a feedback control circuit (not shown) to adjust the magnitude of current flow in magnets  110  and  130 . Such variations in electromagnet repulsion forces may be required between magnet pairs  225 / 130  and  235 / 130  to accommodate gondola loading and on sudden vertical movements. Likewise, such variations in electromagnet repulsion forces may be required between magnet pairs  210 / 110  and  2305 / 130  to counter horizontal inertial forces on turns. 
     In a further alternate embodiment, represented by  FIG. 2 , the permanent magnets of the electromagnets of both the stator  30  and the rotor  40  may be replaced by cores of non-magnetized permeable ferro-iron materials well known in the electrical arts. 
     In the less complex operating mode, where the stator&#39;s magnets are solenoids, the stator circuit receives PDC, and, generates electromagnetic repulsion and traction forces with respect to the rotor&#39;s magnets, assuming they are only simple permanent magnets. When PDC failure occurs, the rotor sets down onto the stator supported by wheels  45  ( FIG. 2 ). When the rotor&#39;s magnets are solenoids, normal operation maintains charge in battery  250  by induced current from the stator circuit and operation may continue even with failure of PDC from the stator, albeit at a relatively low level and also provide for braking for a safe stop. 
     Each of the individual stator circuits deriving power from each individual one of circuits  105  (hall sensors and switches) acts as a proximity sensors to identify the approach of each rotor circuit. Until a rotor circuit approaches the switch of circuit  105  places the respective stator circuit in short circuit status, which induces PDC in the short circuited stator circuit as the approaching rotor circuit passes; an equivalent operation to normal operation. 
     As the rotor circuit approaches each hall sensor it detects an approaching magnetic field pole and switches the polarity of the PDC to accommodate the linear electric motor function. As the rotor circuit leaves the proximity of each stator circuit, the hall sensor is immersed in the end effect of the magnetic field associated with magnets  220  of the rotor  40  and then switches the polarity of the PDC to eliminate the braking function, after which short circuit condition is restored until the next rotor circuit approaches. 
       FIGS. 7-10  show electrical component placement and interactions between rotor and stator as described above, using the symbol set defined in  FIG. 7 . 
     In case of a power failure of the stator electrical system, the electrical generator  270  of the rotor electrical circuit shown in  FIG. 5  is started up, switch S 1  is closed and PDC is provided to the rotor circuit. In this case the PDC in inducted in coils  106 ,  110  and  130  of the stator, with the effect of maintaning rotor levitation, stability and thrust. If battery  250  fails, generator  270  is switched into the rotor circuit to energize its electromagnets. In case complete power failure occurs the rotor  40  will “fall” such that wheels  45  ( FIG. 2 ) will touch down and roll on track  30  as shown in  FIG. 2 . 
     The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of the apparatus and its method of use and to the achievement of the above described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specification and by the word or words describing the element. 
     The definitions of the words or drawing elements described herein are meant to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements described and its various embodiments or that a single element may be substituted for two or more elements in a claim. 
     Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalents within the scope intended and its various embodiments. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. This disclosure is thus meant to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted, and also what incorporates the essential ideas. 
     The scope of this description is to be interpreted only in conjunction with the appended claims and it is made clear, here, that each named inventor believes that the claimed subject matter is what is intended to be patented.