Patent Publication Number: US-2022224174-A1

Title: Modular electromagnetic machines and methods of use and manufacture thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and benefit of U.S. Provisional Patent Application No. 62/578,508 filed Oct. 29, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to electromagnetic machines used for converting electrical energy to mechanical energy, and vice-versa. More specifically, the present disclosure relates to the use of an electromagnetic machine with modular components and an access window. 
     BACKGROUND 
     Current electromagnetic machines and methods of use thereof have operational constraints limiting their utility in a variety of applications. The limitations can be traced to design, manufacturing processes and other physical constraints, such as accessing components of the electromagnetic machines for repair or modifying electromagnetic machines for new uses. New devices and methods for using those devices are needed that can improve the functional utility and customizability of electromagnetic machines for different applications. The present disclosure is directed to solving those problems, as well as solving other problems. 
     SUMMARY 
     According to aspects of the present disclosure, an electromagnetic machine comprises a housing; an axle coupled to the housing in a rotatable fashion; a stator assembly disposed generally within the housing, the stator assembly including a stator plate and a stator bearing positioned within an opening formed in the stator plate, the stator bearing being coupled to the axle such that the stator assembly is rotatable about the axle; a rotor assembly fixed to the axle and disposed generally within the housing and including a rotor housing that defines a circumferentially extending channel that is sized to receive a portion of the stator assembly therein; and a locking mechanism configured to selectively prevent and permit rotation of the stator assembly about the axle via the stator bearing. 
     According to further aspects of the present disclosure, an electromagnetic machine comprises a housing having an access window defined therein; an axle coupled to the housing in a rotatable fashion; a stator assembly disposed generally within the housing, the stator assembly including a plurality of coils mounted thereon; a rotor assembly disposed generally within the housing and including a rotor housing that defines a circumferentially extending channel that is sized to receive a portion of the stator assembly therein; and a locking mechanism configured to selectively prevent and permit rotation of the stator assembly about the axle via the stator bearing, wherein the access window is configured to provide access to at least one coil of the plurality of coils. 
     According to additional aspects of the present disclosure, a method of servicing an electromagnetic machine comprises removing an access window cover from a housing of the electromagnetic machine to provide access to a stator assembly through an access window defined in the housing; electrically disconnecting an existing coil module from a portion of a circuit board disposed on the stator assembly; removing the portion of the circuit board; replacing the at least one coil module with a new coil module; replacing the portion of the circuit board; electrically connecting the new coil module to the portion of the circuit board; coupling the access window cover to the housing of the electromagnetic machine to prevent access to the stator assembly. 
     According to still further aspects of the present disclosure, an electromagnetic machine comprises a housing including a first wall having a first bearing opening defined therein and the opposing second wall having a second bearing opening defined therein, the first wall further having an access window defined therein; a first bearing coupled to the first bearing opening of the first wall; a second bearing coupled to the second bearing opening of the opposing second wall; an axle coupled to the first bearing and coupled to the second bearing such that the axle is rotatable relative to the first wall and the opposing second wall of the housing; a stator assembly disposed generally between the first wall and the opposing second wall of the housing, the stator assembly including a circumferentially extending coil housing mounted to a stator plate and a stator bearing positioned within a stator opening formed in the stator plate, the stator bearing being coupled to the axle such that the stator assembly is rotatable about the axle, the stator assembly further including a plurality of coil modules mounted in the coil housing and a circuit board disposed between the first wall of the housing and the plurality of coil modules, the circuit board including a plurality of separate and distinct circuit board sections that are electrically coupled together, each of the circuit board sections being electrically connected to a respective portion of the plurality of coil modules, the circuit board being accessible through the access window defined in the first wall of the housing; a rotor assembly disposed generally between the first wall and the opposing second wall of the housing, the rotor assembly including a rotor housing that is non-rotationally coupled to the axle and defines a circumferentially extending channel, the circumferentially extending channel defining a first surface, an opposing second surface, and a third surface, the first surface and the opposing second surface being generally parallel, the third surface being generally orthogonal to the first surface and the opposing second surface and connecting the first surface to the second surface, the rotor assembly further including a plurality of magnet sets disposed within the circumferentially extending channel such that the plurality of magnet sets surround the axle in a circumferential fashion, each of the plurality of magnet sets including a first magnet coupled to the first surface defined by the channel, an opposing second magnet coupled to the opposing second surface defined by the channel, and a third magnet coupled to the third surface defined by the channel, the circumferentially extending channel being sized to at least partially receive the coil housing of the stator assembly therein such that each of the plurality of coil modules mounted in the coil housing is at least partially disposed within the circumferentially extending channel; and a locking mechanism configured to selectively prevent and permit rotation of the stator assembly about the axle via the stator bearing. 
     According to further aspects of the present disclosure, an electromagnetic machine comprises a housing; a bearing assembly disposed in an opening defined in the housing; a stator assembly disposed generally within the housing, the stator assembly including a stator mount defining an opening, the bearing assembly being further disposed in the opening defined by the stator mount; an axle coupled to the bearing assembly in a rotatable fashion such that the axle is rotatable relative to the housing and the stator assembly; a rotor assembly fixed to the axle and disposed generally within the housing and including a rotor housing that defines a circumferentially extending channel that is sized to receive a portion of the stator assembly therein; and a locking mechanism configured to selectively prevent and permit rotation of the stator assembly about the axle. 
     According to still further aspects of the present disclosure, an electromagnetic machine comprises a housing; a stator assembly disposed generally within the housing; one or more bearings disposed at least partially within the housing; an axle coupled to the one or more bearings in a rotatable fashion such that the axle is rotatable relative to the housing and the stator assembly; a rotor assembly fixed to the axle and disposed generally within the housing and including a rotor housing that defines a circumferentially extending channel that is sized to receive a portion of the stator assembly therein; and a locking mechanism configured to selectively prevent and permit rotation of the stator assembly about the axle. 
     According to still further aspects of the present disclosure, an electromagnetic machine comprises a housing including a first wall having a first opening defined therein and the opposing second wall, the first wall further having an access window defined therein; a stator assembly disposed generally between the first wall and the opposing second wall of the housing, the stator assembly defining a second opening therein, the stator assembly including a plurality of coil modules containing a coil and a corresponding core; a bearing assembly extending at least partially though the first opening in the first wall and the second opening in the stator assembly, the bearing assembly being non-rotationally coupled to the first wall and the stator assembly, the bearing assembly including a first bearing and a second bearing, the first bearing positioned generally coincident with the first opening in the first wall, the second bearing positioned generally between the second opening in the stator assembly and the second wall; an axle rotationally coupled to the bearing assembly such that the axle is rotatable relative to the first wall and the stator assembly; and a rotor assembly non-rotationally coupled to the axle, the rotor assembly including a plurality of magnets positioned adjacent to the plurality of coil modules. 
     The foregoing and additional aspects and implementations of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various implementations and/or implementations, which is made with reference to the drawings, a brief description of which is provided next. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other advantages of the present disclosure will become apparent upon reading the following detailed description and upon reference to the drawings. 
         FIG. 1A  is a perspective view of an implementation of an electromagnetic machine, according to aspects of the present disclosure; 
         FIG. 1B  is an additional perspective view of the implementation of the electromagnetic machine of  FIG. 1A , according to aspects of the present disclosure; 
         FIG. 2A  is an exploded perspective view of the implementation of the electromagnetic machine of  FIG. 1A , according to aspects of the present disclosure; 
         FIG. 2B  is an additional exploded perspective view of the implementation of the electromagnetic machine of  FIG. 1A , according to aspects of the present disclosure; 
         FIG. 3A  is a perspective view of an implementation of a stator assembly, according to aspects of the present disclosure; 
         FIG. 3B  is an additional perspective view of the implementation of the stator assembly of  FIG. 3A , according to aspects of the present disclosure; 
         FIG. 3C  is an exploded perspective view of the implementation of the stator assembly of  FIG. 3A , according to aspects of the present disclosure; 
         FIG. 3D  is an additional exploded perspective view of the implementation of the stator assembly of  FIG. 3A , according to aspects of the present disclosure; 
         FIG. 4  is an enlarged perspective view of the implementation of the stator assembly of  FIG. 3A , according to aspects of the present disclosure; 
         FIG. 5A  is an exploded perspective view of an implementation of a coil housing, according to aspects of the present disclosure; 
         FIG. 5B  is an additional exploded perspective view of the implementation of the coil housing of  FIG. 5A , according to aspects of the present disclosure; 
         FIG. 6A  is an enlarged perspective view of the implementation of the coil housing of  FIG. 5A , according to aspects of the present disclosure; 
         FIG. 6B  is an additional enlarged perspective view of the implementation of the coil housing of  FIG. 5A , according to aspects of the present disclosure; 
         FIG. 7A  is a perspective view of an implementation of a rotor assembly, according to aspects of the present disclosure; 
         FIG. 7B  is an additional perspective view of the implementation of the rotor assembly of  FIG. 7A , according to aspects of the present disclosure; 
         FIG. 7C  is a perspective view of a rotor housing of the implementation of the rotor assembly of  FIG. 7A , according to aspects of the present disclosure; 
         FIG. 7D  is a cross-sectional view of the rotor housing of  FIG. 7C , according to aspects of the present disclosure; 
         FIG. 8  is a cross-sectional view of the electromagnetic machine of  FIG. 1A , according to aspects of the present disclosure. 
         FIG. 9A  is a perspective view of another implementation of an electromagnetic machine, according to aspects of the present disclosure; 
         FIG. 9B  is an additional perspective view of the implementation of the electromagnetic machine of  FIG. 9A , according to aspects of the present disclosure; 
         FIG. 10A  is an exploded perspective view of the implementation of the electromagnetic machine of  FIG. 9A , according to aspects of the present disclosure; 
         FIG. 10B  is an additional exploded perspective view of the implementation of the electromagnetic machine of  FIG. 9A , according to aspects of the present disclosure; 
         FIG. 11A  is a perspective view of an axle and a bearing assembly, according to aspects of the present disclosure; 
         FIG. 11B  is an additional perspective view of the axle and bearing assembly of  FIG. 11A , according to aspects of the present disclosure; 
         FIG. 11C  is an exploded perspective view of the axle and bearing assembly of  FIG. 11A , according to aspects of the present disclosure; 
         FIG. 11D  is a cross-sectional view of the axle and bearing assembly of  FIG. 11A , according to aspects of the present disclosure; 
         FIG. 12A  is a perspective view of another implementation of a stator assembly, according to aspects of the present disclosure; 
         FIG. 12B  is an additional perspective view of the implementation of the stator assembly of  FIG. 12A , according to aspects of the present disclosure; 
         FIG. 12C  is an exploded perspective view of the implementation of the stator assembly of  FIG. 12A , according to aspects of the present disclosure; 
         FIG. 12D  is an additional exploded perspective view of the implementation of the stator assembly of  FIG. 12A , according to aspects of the present disclosure; 
         FIG. 13A  is an enlarged perspective view of the implementation of the stator assembly of  FIG. 12A , according to aspects of the present disclosure; 
         FIG. 13B  is a perspective view of a coil of the stator assembly of  FIG. 12A , according to aspects of the present disclosure; 
         FIG. 14A  is an exploded perspective view of another implementation of a coil housing, according to aspects of the present disclosure; 
         FIG. 14B  is an additional exploded perspective view of the implementation of the coil housing of  FIG. 14A , according to aspects of the present disclosure; 
         FIG. 15A  is an enlarged perspective view of the implementation of the coil housing of  FIG. 14A , according to aspects of the present disclosure; 
         FIG. 15B  is an additional enlarged perspective view of the implementation of the coil housing of  FIG. 14A , according to aspects of the present disclosure; 
         FIG. 16A  is a perspective view of another implementation of a rotor assembly, according to aspects of the present disclosure; 
         FIG. 16B  is an additional perspective view of the implementation of the rotor assembly of  FIG. 16A , according to aspects of the present disclosure; 
         FIG. 16C  is a perspective view of a rotor housing of the implementation of the rotor assembly of  FIG. 16A , according to aspects of the present disclosure; 
         FIG. 16D  is a cross-sectional view of the rotor housing of  FIG. 16C , according to aspects of the present disclosure; 
         FIG. 17  is a cross-sectional view of the electromagnetic machine of  FIG. 9A , according to aspects of the present disclosure. 
     
    
    
     While the present disclosure is susceptible to various modifications and alternative forms, specific implementations and implementations have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the present disclosure is not intended to be limited to the particular forms disclosed. Rather, the present disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims. 
     DETAILED DESCRIPTION 
     According to aspects of the present disclosure, electromagnetic machines can be used both to convert non-electrical energy into electrical energy (a generator) and to convert electrical energy into non-electrical energy (a motor). Electromagnet machines for such uses generally include a rotating component called a rotor and a stationary component called a stator. Generally, the rotor is coupled to an axle, such that rotation of the rotor causes corresponding rotation of the axle. Conversely, rotation of the axle causes corresponding rotation of the rotor. In at least some implementations, the stator can include one or more coil modules, which include a coil of wire optionally wrapped around a core. The rotor can then include one or more magnets, which can include radial magnets and axial magnets. In at least some implementations, the stator contains one or more magnets (radial and/or axial) while the rotor contains one or more coil modules. When the electromagnetic machine is used as a generator, an external component is coupled to the axle to cause rotation of the rotor. This external component can be referred to as a prime mover, and could be, for example, a turbine or a water wheel. Rotation of the prime mover causes rotation of the axle, which in turn causes the rotor to rotate relative to the stator. As the rotor rotates relative to the stator, current is induced in the coil modules, which can then optionally be used to store electrical energy in an electric storage device. When the electromagnetic machine is used as a motor, an electric power source is coupled to the coil modules. Current is caused to flow through the coil modules, which creates a magnetic field. This magnetic field interacts with the magnets disposed in the electromagnetic machine, which causes the rotor and thus the axle to rotate. The rotation of the axle can then be utilized for any suitable purpose. 
     Referring now to  FIG. 1A  and  FIG. 1B , an exemplary electromagnetic machine  100  includes a housing  102  having a first wall  104 A, a second wall  104 B, a cover panel  106 , and a base  108 . The electromagnetic machine  100  includes a connection box  110 . The connection box  110  houses electrical components that electrically connect the internal components of the electromagnetic machine  100  to an electric power source, an electric load, or an electric storage device, depending on how the electromagnetic machine is to be used. The first wall  104 A of the housing  102  includes one or more access windows  112  defined therein that allow access to the internal components of the electromagnetic machine  100 . The access window  112  has a surface area that is a percentage of the surface area of the first wall  104 A of the housing  102  without the access window  112  defined therein. A ratio of the surface area of the access window  112  to the surface area of the first wall of the housing  102  can be between about 5% and about 50%, between about 20% and about 40%, between about 15% and about 30%, about 25%, or about 8.33%. 
     The first wall  104 A of the housing  102  includes one or more access window covers  114  removably coupled thereto. The access window covers  114  are configured to cover the access windows  112 , which prevents access to the internal components of the electromagnetic machine  100  and protects those components. Generally, each access window  112  will have a corresponding access window cover  114 . The access window covers  114  can be coupled to the first wall  104 A of the housing  102  in any suitable fashion, such as with screws, bolts, clips, etc. During operation of the electromagnetic machine  100 , each access window cover  114  is coupled to the first wall  104 A of the housing  102  such that an individual or any other object cannot contact any internal components that may be rotating, moving, energized, or otherwise in use. When the electromagnetic machine is not in use, the access window covers  114  can be removed so that the individual can safely access the internal components through the access window  112 . 
     The first wall  104 A of the housing  102  has a first opening defined therein at which a first bearing  116 A is coupled. Similarly, the second wall  104 B of the housing  102  has a second opening defined therein at which a second bearing  116 B is coupled. An axle  105  is generally disposed through the first wall  104 A and the second wall  104 B, and is coupled to the first bearing  116 A and the second bearing  116 B such that the axle  105  is rotatable relative to the first wall  104 A and the second wall  104 B. The housing  102  can also have a number of air flow apertures defined therein to allow air to flow through the housing  102  during operation. For example, first wall  104 A and second wall  104 B can have air flow apertures  118 A and  118 B, respectively, defined therein. Similarly, cover panel  106  can include air flow apertures  118 C. The air flow can help to cool the internal components of the electromagnetic machine  100  and keep the temperature of the machine within an acceptable range, thus allowing the electromagnetic machine  100  to be used in a wider variety of conditions and scenarios. The first wall  104 A, second wall  104 B, cover panel  106 , base  108 , and internal components can be mechanically coupled by a variety of means, such as screws, nails, bolts, pins, clips, welds, or any other suitable coupling mechanism. In an implementation, the second wall  104 B is not an independent component of the housing  102 . Rather, the second wall  104 B can be a portion of a separate component that is coupled to the electromagnetic machine  100 , such as a portion of the housing of the prime mover. In a further implementation, the second wall  104 B of the housing can be an outer housing of the rotor. 
     Exploded views of the electromagnetic machine of  FIG. 1A  and  FIG. 1B  are shown in  FIG. 2A  and  FIG. 2B , respectively. The first wall  104 A of the housing  102  is shown with access window cover  114 A exploded from access window  112 A, while access window cover  114 B remains attached to the first wall  104 A of the housing  102 . The first bearing opening  120 A is defined in the first wall  104 A of the housing  102 . The second bearing opening  120 B is defined in the second wall  104 B of the housing  102 . The internal components of the electromagnetic machine  100  include a stator assembly  200  and a rotor assembly  300 , which includes the axle  105 . The stator assembly is disposed generally between the first wall  104 A and the rotor assembly  300 , while the rotor assembly is disposed generally between the stator assembly  200  and the second wall  104 B. 
     In an implementation of the electromagnetic machine  100 , the stator assembly  200  includes one or more coil modules, which include coils of wire that are wrapped around a permeable core of magnetic material, while the rotor assembly  300  includes one or more magnets configured to be disposed adjacent to the coils of wire when the electromagnetic machine  100  is in use. In another implementation, the stator assembly  200  includes the magnets while the rotor assembly  300  contains the coil modules. As will be described in more detail herein, the rotor assembly  300  generally defines a channel around which the magnets are disposed. During operation of the electromagnetic machine  100 , the coil modules that are attached to the stator assembly  200  are disposed within the channel defined by the rotor assembly  300 . 
     The first wall  104 A of the housing  102  includes one or more housing locking apertures  122  defined therein. Similarly, the stator assembly  200  includes one or more stator assembly locking apertures  222  defined therein. Each of the housing locking apertures  122  and the stator assembly locking apertures  222  are sized such that a locking mechanism may be removably inserted therethrough to prevent the rotation of the stator assembly about the axle via the stator bearing. During operation of the electromagnetic machine  100 , the stator assembly  200  can be locked into place to prevent any unnecessary or undesired movement. When the electromagnetic machine  100  needs to be serviced, the locking mechanism can be removed from the housing locking apertures  122  and the stator assembly locking apertures  222  to allow the stator assembly to be rotated until a desired portion of the stator assembly is accessible through the access windows. The locking mechanism can be, for example, a bolt, a pin, a spring-loaded pin, or a linearly actuated pin. In other implementations, locking mechanisms that do not utilize apertures defined in the housing and the stator could be used, such as clips or fasteners. While the figures show potential locations of the housing locking apertures  122  and the stator assembly locking apertures  222 , these apertures can be defined anywhere on the electromagnetic machine  100  as long as a locking mechanism can be inserted through both apertures to thereby prevent rotation of the stator assembly relative to the housing. 
       FIGS. 3A and 3B  illustrates perspective views of the stator assembly  200 , while  FIG. 3C  and  FIG. 3D  illustrate exploded views of the stator assembly  200  of  FIG. 3A  and  FIG. 3B , respectively. The stator assembly  200  generally includes a stator plate  210 , a circuit board  230 , and a coil housing  240  mounted to the stator plate  210 . The coil housing  240  includes slots in which the coil modules may be disposed during operation of the electromagnetic machine  100 . The stator plate  210  generally includes a stator plate hub  212  and a circumferentially extending stator plate ring  214 . The stator plate hub  212  has a stator bearing opening  216  defined therein. A stator bearing  218  is coupled to the stator bearing opening  216 . When the components of the electromagnetic machine  100  are assembled, the stator bearing  218  allows the stator assembly  200  to rotate relative to the axle  105 . Similarly, the stator bearing  218  allows the axle  105  to rotate relative to the stator assembly  200 . The stator assembly locking apertures  222  are defined in the stator plate ring  214 . Stator bearing  218  may be removably coupled to the stator bearing opening  216 , and thus may be movable along the axle  105  to allow for down-time repairs of the electromagnetic machine  100 . 
     For example, if the first bearing  116 A fails, the axle may become insufficiently supported by the first bearing  116 A, which could allow the axle  105  or the rotor assembly  300  come into contact with the housing  102  or the stator assembly  200 . Normally, the machine would need to be shut down until a replacement part was procured and coupled to the first bearing opening  120 A to thus support the axle  105 . However, the stator bearing  218  of the electromagnetic machine  100  is movable between a first position and a second position. In the first position, the stator bearing  218  is disposed at least partially within the stator bearing opening  216  to thus support the stator. In the second position, the stator bearing  218  is disposed at least partially within the first bearing opening  120 A defined in the first wall  104 A of the housing  102 . In this second position, the stator bearing  218  supports the axle  105  and prevents the axle  105  from coming into contact with any other components of the electromagnetic machine  100 . In an implementation, a depth of the stator bearing  218  is less than the shortest distance between the first bearing opening  120 A and the stator bearing opening  216 . In this implementation, the first bearing  116 A must remain at least partially within the first bearing opening  120 A to support the axle  105  until the stator bearing is disposed at least partially within the first bearing opening  120 A. In another implementation, the depth of the stator bearing  218  is greater than the shortest distance between the first bearing opening  120 A and the stator bearing opening  216 , and thus is able to be at least partially disposed within both the first bearing opening  120 A and the stator bearing opening  216 . 
     The stator plate  210  further includes a circumferentially extending alignment plate  220  ( FIGS. 3C and 3D ) that is disposed at least partially between the stator plate hub  212  and the stator plate ring  214 . Alignment plate  220  has a generally circular shape with an opening defined in the center thereof, and thus has an inner periphery and an outer periphery. The inner periphery of the alignment plate  220  overlaps with and is coupled to a periphery of the stator plate hub  212 , while the outer periphery of the alignment plate  220  overlaps with and is coupled to an inner periphery of the stator plate ring  214 . In an implementation, the alignment plate  220  is modular and is formed from a plurality of separate and distinct alignment plate sections that are disposed about the stator plate hub  212 . In another implementation, the alignment plate  220  is a single unitary piece. 
     The circuit board  230  is coupled to and generally overlaps with the alignment plate  220 . Similar to the alignment plate  220 , the circuit board  230  can be modular and thus can be formed from a plurality of separate and distinct circuit board sections. Each of the circuit board section can correspond to one of the alignment plate sections. The circuit board sections can be electrically connected together by one or more circuit board jumpers  232 , and are generally attached to the alignment plate sections via fasteners, such as screws, rods, pins, etc. In another implementation, the circuit board  230  is a single unitary piece. The electrical connections between the circuit board  230  can be designed in any manner required for the specific application of the electromagnetic machine  100 , and may be replaced from time to time as application requirements change. As will be described in more detail herein, the alignment plate  220  is used to align the electrical leads from the coil modules with the circuit board sections, and to assist in maintaining contact between the electrical leads from the coil modules and the circuit board  230 . 
     The stator plate hub  212  is connected to the stator plate ring  214  via one or more stator plate mounting brackets  242 . Each stator plate mounting bracket  242  has a first end coupled to the stator plate hub  212  and a second end coupled to the stator plate ring  214 . The stator plate mounting brackets  242  also couple to the coil housing  240 , thus coupling the coil housing  240  to the stator plate  210 . The stator plate mounting brackets  242  may be coupled to the other component using any suitable mechanism, such as screws, pins, bolts, etc. 
     The arrangement between the coil modules, the circuit board, and the alignment plate is illustrated in  FIG. 4 .  FIG. 4  illustrates three portions  201 A,  201 B, and  201 C of the stator assembly  200 . The first portion  201 A includes circuit board section  231 A and an underlying alignment plate section  221 A underneath the circuit board section  231 A. The second portion  231 B shows the circuit board section removed, leaving only the underlying alignment plate section  221 B. The third portion  201 C shows both the circuit board section and the underlying alignment plate section removed. As shown, each of the plurality of coil modules includes two coil leads  225 A and  225 B extending out of the coil housing toward the alignment plate and the circuit board. As shown with alignment plate section  221 A, each alignment plate section includes a set of alignment plate coil lead apertures  224  that are configured to receive the coil leads  225 A and  225 B of each of the coil modules. In an implementation, the coils leads  225 A,  225 B are configured to extend out of the alignment plate coil lead apertures  224  and be bent at approximately a ninety degree angle, thus leaving terminating ends  226 A,  226 B of the coil leads  225 A,  225 B flush with the surface of the alignment plate section  221 A. 
     As shown with respect to the first portion  201 A, the circuit board sections are disposed directly on top of the alignment plate sections, thus sandwiching the terminating ends  226 A,  226 B of the coil leads  225 A,  225 B between the alignment plate section and the circuit board section. In this configuration, the terminating ends  226 A,  226 B of the coil leads  225 A,  225 B contact the circuit board at respective circuit board contact areas, thus electrically connecting the coil modules to the circuit boards. The alignment plate sections help to align the terminating ends  226 A,  226 B of the coil leads  225 A,  225 B with the appropriate circuit board contact area. The pressure on the terminating ends  226 A,  226 B of the coil leads  225 A,  225 B also helps to maintain the electrical connection between the coil modules and the circuit board. In an implementation, each circuit board section has a plurality of circuit board coil lead apertures  227  defined therein that correspond to the plurality of the alignment plate coil lead apertures  224 . In this implementation, an alignment component, such as a screw, bolt, pin, clamp, etc., can be inserted through the circuit board coil lead apertures  227  and the alignment plate coil lead apertures  224 . This serves both to couple the circuit board section and the alignment plate section together, and to assist in completing and maintaining the electrical connection between the coil leads  225 A,  225 B and the circuit board section. The alignment component can be electrically conductive and can be configured to contact both the circuit board when disposed through the circuit board coil lead apertures, and the terminating ends  226 A,  226 B of the coil leads  225 A,  225 B, thus helping to ensure that the coil leads  225 A,  225 B are electrically connected to the circuit board. 
     Referring now to  FIG. 5A  and  FIG. 5B , the coil housing  240  includes a first coil housing ring  244  and a second coil housing ring  246 . The coil housing rings  244 ,  246  define the slots into which the coils  243  and the corresponding permeable coil cores  251  (see  FIGS. 6A and 6B ) are inserted. The coil housing  240  further includes a plurality of independent core modules  248  that are disposed between the first coil housing ring  244  and the second coil housing ring  246 . A plurality of backing components  250  are also disposed on a side of the coil housing  240  opposite the side of the coil housing  240  where the coils  243  are inserted. The coil housing includes one or more of the stator plate mounting brackets  242  coupled thereto, as well as one or more coil housing mounting brackets  252  disposed on an opposite side of the coil housing  240  from the stator plate mounting brackets  242 . 
     A plurality of coil housing mounting components  254  are configured to couple each of the stator plate mounting brackets  242  to a corresponding one of the coil housing mounting brackets  252  or to the first coil housing ring  244 , providing tension that holds all components of the coil housing  240  in position. The coil housing mounting components  254  generally include an inner set of coil housing mounting components and an outer set of coil housing mounting components. Each coil housing mounting component  254  of the outer set is configured to extend (i) from the outer periphery of one of the stator plate mounting brackets  242 , (ii) through the outer periphery of the first coil housing ring  244 , the outer periphery of one of the independent core modules  248 , and the outer periphery of the second coil housing ring  246 , and to (iii) the outer periphery of one of the coil housing mounting brackets  252 . Similarly, each coil housing mounting component  254  of the inner set is configured to extend (i) from the inner periphery of one of the stator plate mounting brackets  242 , (ii) through the inner periphery of the first coil housing ring  244 , the inner periphery of one of the independent core modules  248 , and the inner periphery of the second coil housing ring  246 , and to (iii) the inner periphery of one of the coil housing mounting brackets  252 . Generally, each of the coil housing mounting components  254  are bolts, pins, screws, etc. Thus, the various components of the coil housing  240  are coupled together, and the coil housing  240  is coupled to the stator plate  210  via the stator plate mounting brackets  242 . 
     Detailed views of the coil housing  240  are illustrated in  FIG. 6A  and  FIG. 6B . Various portions of the components of the coil housing  240  have been removed from the figures to show internal details. As shown, each coil  243  includes a corresponding permeable coil core  251 . In this manner, each coil  243  is wound around its own individual core  251 . The coil cores  251  can be made of a ferromagnetic material, such as laminated electrical steel. In some implementations, each individual core  251  are configured to be disposed completely within its corresponding coil  243 . In other implementations, each individual core  251  is disposed partially within its corresponding coil  243  such that at least a portion of each core  251  extends outside of the bounds of its corresponding coil  243 . In some implementations, each coil  243  can have a generally rectangular shape that includes a first side surface  260 A, a second side surface  260 B, and a third side surface  260 C. The cores  251  can have a similar generally rectangular shape. Other shapes for the coils  243  and the cores  251  are also contemplated. 
     The coil housing  240  includes the first coil housing ring  244  and the second coil housing ring  246 . Each of these coil housing rings can be made of a ferromagnetic material such as laminated electrical steel. Both of the coil housing rings  244 ,  246  are generally circular shaped and have an inner periphery and an outer periphery. The first coil housing ring  244  includes a plurality of repeating columns  245 A connecting the inner periphery and the outer periphery of the first coil housing ring  244 . The first coil housing ring also defines a plurality of gaps  245 B. Each gap  245 B is defined between adjacent columns  245 A and is sized such that the coils fit through the gaps  245 B. 
     Similarly, the second coil housing ring  246  also includes a plurality of repeating columns  247 A connecting the inner periphery and the outer periphery of the second coil housing ring  246 . The second coil housing ring  246  defines a plurality of gaps  247 B. Each gap  247 B is defined between adjacent columns  247 A and is sized such that the coils  243  fit through the gaps  247 B. The gaps  245 B defined in the first coil housing ring  244  and the gaps  247 B defined in second coil housing ring  246  overlap, and thus the first coil housing ring  244  and the second coil housing ring  246 , when assembled as part of the coil housing  240 , define the plurality of slots  241  which are sized to receive a plurality of coils  243 , each slot  241  receiving a single coil  243 . 
       FIGS. 6A and 6B  show two of the independent core modules  248  that are disposed between the first coil housing ring  244  and the second coil housing ring  246 . The independent core modules  248  can be made of a ferromagnetic material similar to the other components of the coil housing  240 , such as laminated electrical steel. The independent core modules  248  are disposed between the first coil housing ring  244  and the second coil housing ring  246  such that an end of each of the independent core modules  248  adjacent the first coil housing ring  244  abuts one of the columns  245 A, while an opposing end of each of the independent core modules  248  adjacent the second coil housing ring  246  abuts a corresponding one of the columns  247 A. The independent core modules  248  are disposed in areas between the first coil housing ring  244  and the second coil housing ring  246  that would otherwise be empty space between adjacent coils  243 . Thus, when the coil  243  and corresponding core  251  of  FIGS. 6A and 6B  is received within the slots  241  of the coil housing  240 , the coil  243  and corresponding core  251  will be disposed between the pair of independent core modules  248  that are illustrated in  FIGS. 6A and 6B . When the electromagnetic machine  100  is fully assembled, each coil  243 -core  251  combination will be disposed between a pair of adjacent independent core modules  248 . 
     In some implementations, each of the independent core modules  248  includes an outer radial lip  257  and in inner radial lip  258 . The outer radial lip  257  of each of the independent core modules  248  is configured to extend over the first side surface  260 A of a corresponding one of the coils  243 . Similarly, the inner radial lip  258  of each of the independent core modules  248  is configured to extend over the second side surface  260 B of a corresponding one of the coils  243 . The presence of the radial lips  257 ,  258  reduces or eliminates any gaps between the side surfaces  260 A,  260 B of the coils  243  and the radial magnets of the electromagnetic machine  100 . This helps to channel magnetic flux from the radial magnets to the coils  243  more efficiently. 
     The plurality of backing components  250  and the plurality of coil housing mounting brackets  252  are disposed on a side of the coil housing  240  opposing the stator plate  210 . The backing components  250  can be made of a ferromagnetic material similar to other components of the coil housing  240 , such as laminated electrical steel. Each of the backing components  250  has a groove defined therein that is configured to mate with an edge of a corresponding coil housing mounting bracket  252  such that the backing components  250  and the coil housing mounting brackets  252  interlock with each other. Each backing component  250  includes an axial lip  259  that is configured to extend over the third side surface  260 C of a corresponding one of the coils  243 . The axial lips  259  of the backing components  250  reduce or eliminate any gaps between the third side surface  260 C and the axial magnets of the electromagnetic machine  100 . This helps to channel magnetic flux from the axial magnets to the coils  243  more efficiently. 
     The ferromagnetic components of the coil housing  240  can include the first coil housing ring  244 , the second coil housing ring  246 , the independent core modules  248 , the backing components  250 , and the coil cores  251 . All of the components of the coil housing  240  can be high permeability materials with low hysteresis and related core losses, which may be utilized to maximize the strength of the magnetic field in the region of the coil housing  240 . 
     The combination of the access windows defined in the housing of the electromagnetic machine, the stator being coupled to the axle via the independent stator bearing, the circuit board and alignment plate being formed in sections, and the coil modules being housed in individual slots within the coil housing allows the electromagnetic machine to be a modular machine where individual coil modules can be replaced, repaired, or upgraded without having to take apart or disassemble the entire machine. The circuit board sections can be easily swapped out to wire the coil modules in different arrangements, thus allowing the electromagnetic machine to be used in a wide variety of applications. By providing the access windows in the housing, an individual is able to access the internal components of the electromagnetic machine without removing the entirety of the housing. This has the added benefit of maintaining alignment between the rotor and the stator. Moreover, the coil modules are simply inserted into individual slots defined in the coil housing for operation, and thus are easy to remove from the electromagnetic machine. 
     Once the access window cover has been removed, the individual can deactivate the locking mechanism to allow the stator assembly to rotate about the stator bearing relative to the housing. The individual can then rotate the stator assembly until the circuit board section or coil modules that needs to be addressed is accessible through the window. Because the circuit board can be formed in separate and distinct sections, only a single circuit board section needs to be removed to access any of the coil modules underneath. Thus, rather than having to electrically disconnect all of the coils of the electromagnetic machine to replace a single coil module, the individual only has to electrically disconnect the coil modules connected to the single circuit board segment. In an implementation, the electromagnetic machine includes seventy-two coil modules circumferentially arranged in the stator and twelve circuit board sections. Thus, each circuit board section is directly electrically connected to only six coils, which reduces the number of coils that need to be detached to remove a circuit board segment from seventy-two coils to six coils. In other implementations, the electromagnetic machine includes 12, 36, 144, or any other number of coil modules, and 3, 4, 6, 24, or any other number of circuit board sections. 
       FIG. 7A  and  FIG. 7B  illustrate perspective views of the rotor assembly  300 , while  FIG. 7C  illustrates a perspective view of a rotor housing  302  of the rotor assembly  300 .  FIG. 7D  illustrates a cross-sectional view along cross-sectional line  7 D indicated in  FIG. 7C . As shown, the rotor assembly  300  houses the magnets of the electromagnetic machine  100 . The rotor assembly includes a rotor housing  302  that is coupled to the axle  105  such that rotation of the axle  105  causes the rotor housing  302  to rotate. Conversely, rotation of the rotor housing  302  causes the axle to rotate. In an implementation, the axle  105  has a rotation locking feature that is configured to non-rotationally mate with a rotation locking feature of the rotor housing  302  to prevent relative rotation between the axle  105  and the rotor housing  302 . The rotation locking feature of the axle  105  can be a protrusion, ring, nub, or other structural feature, while the rotation locking feature of the rotor housing  302  can be a groove or aperture defined in the rotor housing  302 , or vice versa. In another implementation, the axle  105  is fixedly coupled to the rotor housing  302  as a single integral piece. The rotor housing  302  includes a back portion  304 , an outer ring portion  306 , and an inner ring portion  308 . The outer ring portion  306  and the inner ring portion  308  are arranged generally concentrically about the axle, and extend away from a surface  310  of the back portion  304  generally in a first direction. In an implementation, the outer ring portion  306  and the inner ring portion  308  are parallel. In other implementations, the outer ring portion  306  and the inner ring portion  308  can be disposed at angles with respect to each other, or with respect to the back portion  304 . A circumferentially extending channel  312  is defined between the outer ring portion  306  and the inner ring portion  308 . The channel  312  is generally defined by a first surface, a second surface, and a third surface. The first surface is formed from an inner surface  314  of the outer ring portion  306  of the rotor housing  302 . The second surface is formed from an outer surface  316  of the inner ring portion  308  of the rotor housing  302 . The third surface is formed from the portion of the surface  310  of the back portion  304  that is disposed between the outer ring portion  306  and the inner ring portion  308 . Generally, the back portion  304 , the outer ring portion  306 , and the inner ring portion  308  are all formed as a single unitary piece. 
     Generally, the inner surface  314  of the outer ring portion  306  and the outer surface  316  of the inner ring portion  308  are parallel to each other and to a longitudinal axis of the axle  105 . Thus, the first surface and the second surface defined by the channel  312  are generally parallel to each other. The surface  310  of the back portion  304  is generally orthogonal to both the inner surface  314  of the outer ring portion  306  and the outer surface  316  of the inner ring portion  308 . Thus, the third surface defined by the channel  312  is generally orthogonal to both the first surface and the second surface such that the channel  312  has a U-shaped cross section. Other cross-sectional shapes of the channel  312  are also contemplated. 
     The rotor assembly  300  further includes a plurality of magnets disposed within the circumferentially extending channel  312 . The plurality of magnets is disposed in circumferentially extending groups of magnets. As shown in  FIG. 7A , the plurality of magnets includes outer radial magnets  318  coupled to the inner surface  314  of the outer ring portion  306  of the rotor housing  302 . Each adjacent pair of outer radial magnets  318  can be separated by an outer radial spacer  320 . The outer radial magnets  318  and the outer radial spacers  320  are disposed along the circumferentially extending channel  312  such that the outer radial magnets  318  and the outer radial spacers  320  generally encircle the axle  105 . 
     The plurality of magnets further includes inner radial magnets  322  coupled to the outer surface  316  of the inner ring portion  308  of the rotor housing  302 . Each adjacent pair of inner radial magnets  322  can be separated by an inner radial spacer  324 . The inner radial magnets  322  and the inner radial spacers  324  are disposed along the circumferentially extending channel  312  such that the inner radial magnets  322  and the inner radial spacers  324  generally encircle the axle  105 . 
     Finally, the plurality of magnets includes axial magnets  326  coupled to the surface  310  ( FIG. 7C ) of the back portion  304  of the rotor housing  302  between the inner ring portion  308  and the outer ring portion  306 . Like outer radial magnets  318  and inner radial magnets  322 , the axial magnets  326  in the axial group of magnets  326  are disposed along the circumferentially extending channel  312  such that the axial magnets  326  generally encircle the axle  105  or the radius of the inner ring portion  308  of the rotor housing  302 . 
     Each of the magnets  318 ,  322 , and  326  may be coupled to the respective surfaces of the rotor housing  302  in a variety of ways. For example, an adhesive layer can be disposed between the magnets and the surface of the rotor housing  302  to thereby adhesively couple the magnets to the surface of the rotor housing  302 . The magnets can also be screwed into the surface of the rotor housing  302 . In some implementations, the rotor housing  302  can include a retention component that assists in coupling any of the magnets to the rotor housing  302 . The retention component could include one or more clamps or pins that are designed to retain any of the magnets to the corresponding surface. The retention component could also include one or more retaining rings. Generally, the retaining rings are disposed in the channel  312  and are formed to fit around at least a portion of the circumference of the channel  312 . In this manner, the radius of curvature of the retaining ring is generally equal to the radius of the outer ring portion  306  of the rotor housing  302 , or the radius of the inner ring portion  308  of the rotor housing  302 . 
     In the implementation shown in  FIG. 7B , the rotor assembly  300  includes a first retention ring that is formed from first retention ring components  328 A-D. The first retention ring components  328 A-D are disposed at an edge of the outer ring portion  306  that is spaced apart from the back portion  304  of the rotor housing  302 . First retention ring components  328 A-D can be coupled to the rotor housing  302  via screws, adhesive, or any suitable mechanism, and is configured to help hold one edge of each of the outer radial magnets  318  in place. Similarly, a second retention ring that is formed from second retention ring components  330 A-E can be disposed at an edge of the outer ring portion  306  that abuts the back portion  304  of the rotor housing  302 . The second retention ring components  330 A-D help to hold the opposite edge of each of the outer radial magnets  318  in place. The rotor assembly  300  can further include a third retention ring formed from third retention ring components  332 A-D and a fourth retention ring  334  that help to hold each of the inner radial magnets  322  in place. In other implementations, any or all of the retention rings can be formed as single unitary pieces, or can be formed as multiple components. In other implementations, any of the retention rings can instead be retentions pins, which can include or be a dowel. 
     Each of the outer radial magnets  318 , inner radial magnets  322 , and axial magnets  326  can be a dipole magnet with a north pole and a south pole. Each pole of each of the magnets has a corresponding pole face, which is the terminating surface of the magnet corresponding to a respective pole. Thus, opposing surfaces of each of the outer radial magnets  318 , inner radial magnets  322 , and axial magnets  326  are the two pole faces of each magnet. In the rotor assembly  300 , one pole face of each of the magnets faces towards the respective surface defined by the channel to which the magnets are coupled. When the magnets are mounted to the rotor housing  302 , this pole face of each magnet facing the surface defined by the channel abuts and/or contacts the channel. The other opposing pole face of each of the magnets faces away from the respective surface of the channel to which the magnets are coupled. Thus, for each of the outer radial magnets  318 , one of the pole faces abuts the inner surface  314  of the outer ring portion  306  of the rotor housing  302 , while the other pole face of each of the outer radial magnets  318  faces away from the inner surface  314  of the outer ring portion  306  of the rotor housing  302 . For each inner radial magnet  322 , one of the pole faces abuts the outer surface  316  of the inner ring portion  308  of rotor housing  302 , while the other pole face of each of the inner radial magnets  322  faces away from the outer surface  316  of the inner ring portion  308  of rotor housing  302 . For each axial magnet  326 , one pole face abuts the surface  310  of the back portion  304  of the rotor housing  302  between the outer ring portion  306  and the inner ring portion  308 , while the other pole face of each of the axial magnets  326  faces away from the surface  310  of the back portion  304  of the rotor housing  302  between the outer ring portion  306  and the inner ring portion  308 . 
     The groups of magnets  318 ,  322 ,  326  disposed within the channel  312  of the rotor housing  302  can be categorized into sets of magnets. Each set of magnets contains one outer radial magnet  318 , one inner radial magnet  322 , and one axial magnet  326 . The three magnets in each set of magnets can be located at identical circumferential positions within the channel  312  relative to the axle  105 . Thus, a magnet set containing the outer radial magnet  318  located at the three o&#39;clock position within the channel  312  relative to the orientation of the channel  312  in  FIG. 7B  would also contain the inner radial magnet  322  and the axial magnet  326  that are both also located at the three o&#39;clock position. In an exemplary implementation of the electromagnetic machine  100 , the rotor assembly  300  contains twenty-four sets of magnets circumferentially disposed in the channel  312  about the axle  105 . The magnets in each set of magnets can also be staggered in relation to one another, and can also be oriented at a variety of angles with respect to both the surface the magnet is coupled to and the other surfaces of the rotor housing  302 . 
     Each magnet in any given set of magnets has an identical pole face abutting the surface of the rotor housing  302 , as compared to the other magnets in the set. Thus, each magnet in the set of magnets has an identical pole face directed towards the channel  312  itself. The pole face that is directed towards the channel  312  in each magnet set alternates for every circumferentially adjacent magnet set. For example, a first magnet set and a second magnet set may be disposed circumferentially adjacent to each other within the channel  312 . Each magnet in this first magnet set has the same pole face abutting the surface defining the channel. As an example, each of the three magnets in this first magnet set may have the north pole face abutting respective surfaces defining the channel  312 , and thus will have the south pole face facing towards the channel itself. Each magnet in the circumferentially adjacent second magnet face will then have the south pole face abutting the respective surfaces defining the channel  312 , and thus will have the north pole face facing towards the channel itself. 
     This arrangement of alternating pole faces for each magnet set continues circumferentially around the channel  312 . The alternating pole face arrangement of the magnet sets helps to direct the magnetic flux in an alternating and looping fashion through the channel, from the north pole faces to the south pole faces. With the exception of a small air gap region, when the machine is in operation, most of the channel  312  is occupied by the stator assembly  200 , in particular the coil housing  240  which includes the coils  243  and coil cores  251 . The high permeability of the materials in the coil housing  240  increases the magnetic field in the channel, and is designed to channel the flux most efficiently through the coils  243 . 
     In any given set of magnets, one of the pole faces of the outer radial magnet will face toward the first side surface  260 A of the coils  243 . The pole face of the same polarity of the inner radial magnet in the set of magnets will face toward the second side surface  260 B of the coils  243 . The pole face of the same polarity of the axial magnet in the set of magnets will face toward the third side surface  260 C of the coils  243 . During operation of the electromagnetic machine  100 , the rotor will rotate relative to the stator. Thus, the pole faces of the same polarity of the magnets  318 ,  322 ,  326  in a single set of magnets will face toward the respective side surfaces  260 A,  260 B,  260 C of each of the coils  243  in a rotational sequence as the rotor rotates. An adjacent set of magnets will also have pole faces of the same polarity facing toward the respective side surfaces of the coils, except that the pole face will be of the opposite polarity. Because of the alternating polarity of the pole faces of each set of magnets that faces toward the respective side surfaces of the coils  243 , the magnetic flux from the magnets is directed through the coils such that the magnetic flux is normal to a plane that is defined by the coils  243  and/or the cores  251 . 
     The rotor housing  302  can include one or more fan blades  342  coupled thereto. In an implementation, the fan blades  342  can be coupled to the portion of the surface  310  of the back portion  304  that is disposed between the inner ring portion  306  and the axle  105 . The fan blades  342  thus extend outwardly from the surface  310  generally in the first direction, which is the same as the outer ring portion  306  and the inner ring portion  308 . In another implementation, the fan blades  342  are coupled to an inner surface  315  of the inner ring portion  308 , and extend in a radial direction toward the axle  105 . The rotor housing  302  further includes one or more air flow apertures  344  defined in the back portion  304 . During rotation of the rotor assembly  300 , the rotating fan blades  342  direct air through the air flow apertures  344 , thus cooling the internal components of the electromagnetic machine  100 . 
     A cross-section view of the assembled electromagnetic machine  100  is illustrated in  FIG. 8 . The first wall  104 A of the housing is shown, along with the connection box  110 . The axle  105  is coupled to each of the first bearing  116 A, the second bearing  116 B, and the stator bearing  318 . The axle  105  is thus rotatable relative to the housing and the stator assembly. As the stator assembly and the rotor assembly come together in operation, the coils  243  and the corresponding cores  251  are disposed within the U-shaped channel formed by the rotor housing  302 . Finally,  FIG. 8  shows one implementation of a locking mechanism. As can be seen, the locking mechanism includes a locking member  256  inserted through both the first wall  104 A of the housing, and the stator assembly. Thus, while the stator assembly is rotatable relative to the axle  105  due to the stator bearing  218 , the locking member  256  prevents the stator assembly from rotating while the locking member  256  is activated or engaged. 
     As shown in  FIG. 8 , the outer radial magnets  318  generally always face toward the first side surface  260 A of the coils  243 , on both the coil  243  on top, and the coil  243  on the bottom. Similarly, inner radial magnets  322  always face toward the second side surface  260 B of the coils  243 , and the axial magnets  326  always face toward the third side surface  260 C of the coils  243 . 
     Both the design of the rotor housing  302  as a single unitary piece and the axle  105  being supported by bearings on either end enables a very small air gap to be maintained between the coil housing  240  and the surface of the magnets within the rotor housing  302  during operation. Generally, the distance between an outer periphery of the coil housing  240  and the magnets in the rotor housing  302  is about 1.2 millimeters. The size of this air gap is inversely proportional to the output power and efficiency of the electromagnetic machine, with smaller air gaps providing stronger magnetic fields in the coil housing  240  and coil cores  251 . However, tight mechanical tolerances are required to maintain very small air gaps when the machine is in operation. 
     Due to the modular nature of the coils and the circuit board sections, the electromagnetic machine  100  can be configured in a variety of ways. In an implementation, the coils are configured to provide three-phase power. In this implementation, the coils are separated into three different sets of coils, each set of coils corresponding to one of the power phases. Within each phase, the coils can be further divided into two different subsets of coils. Thus, the set of coils for each power phase can comprise two different subsets of series-wired coils, each subset wired in parallel. Each power phase therefore has a backup group of coils. If one of the coils in one subset of a power phase fails, the other subset of coils in that power phase can still provide the power for that phase, as the subsets are wired in parallel. Any number of subsets are contemplated, such as but not limited to two subsets, three subsets, four subsets, or five or more subsets. In a further implementation, all of the coils for each power phase in a multi-phase system are wired together in series. In another implementation, the coils are wired to provide single phase power. The coils in this implementation can be all be wired in series, or can be divided into two or more subsets of coils wired in series, and the subsets being wired together in parallel. In yet a further implementation, the electromagnetic machine includes seventy-two coil modules wired together to provide three-phase power. The first set of coils for the first power phase includes twenty-four coil modules, the second set of coils for the second power phase includes twenty-four coil modules, and the third set of coils for the third power phase includes twenty-four coil modules. Each set of coils is divided into equal subsets wire in parallel, each subset containing twelve coil modules wired in series. 
     To provide service to the electromagnetic machine described herein, the electromagnetic machine must be disconnected from an external electrical power system. A connected prime mover must be stopped and should be locked out. Once the electromagnetic machine is safely isolated and is not operating, an access window cover can be removed from the housing of the electromagnetic machine to provide access to the stator assembly through the access window. A locking mechanism can be deactivated to allow the stator assembly to be rotated within the housing. In an implementation, the locking mechanism is deactivated by removing a locking member from an aperture defined in the housing and an aperture defined in the stator assembly. The stator assembly is then rotated until a desired portion of a circuit board is accessible through the access window. Any coil modules electrically connected to the circuit board section must be disconnected, and then the circuit board section can be removed. The alignment plate section underneath the circuit board section is also removed to provide access to the coil modules. A desired coil module can be removed from the stator assembly, whether for replacement or repair. The coil module is then inserted back into the stator assembly, and the alignment plate section and circuit board section are then replaced. The new coil module is electrically connected to the circuit board, and the access window cover can then be replaced on the housing. The locking mechanism can then be activated to prevent rotation of the stator assembly relative to the housing. In an implementation, the locking mechanism is activated by inserting a locking member into an aperture defined in the housing and an aperture defined in the stator assembly. 
       FIGS. 9A-17  show additional implementations of an electromagnetic machine  1100 . Generally, any of the features of the electromagnetic machine  100  can be combined with the electromagnetic machine  1100 , and any of the features of the electromagnetic machine  1100  can be combined with the electromagnetic machine  100 . 
     Referring now to  FIG. 9A  and  FIG. 9B , an exemplary electromagnetic machine  1100  includes a housing  1102  having a first wall  1104 A, a second wall  1104 B, a cover panel  1106 , and a base  1108 . The electromagnetic machine  1100  includes a connection box  1110 . The connection box  1110  houses electrical components that electrically connect the internal components of the electromagnetic machine  1100  to an electric power source, an electric load, or an electric storage device, depending on how the electromagnetic machine is to be used. The first wall  1104 A of the housing  1102  includes one or more access windows  1112  defined therein that allow access to the internal components of the electromagnetic machine  1100 . The access window  1112  has a surface area that is a percentage of the surface area of the first wall  1104 A of the housing  1102  without the access window  1112  defined therein. A ratio of the surface area of the access window  1112  to the surface area of the first wall of the housing  1102  can be between about 5% and about 50%, between about 20% and about 40%, between about 15% and about 30%, about 25%, or about 8.33%. 
     The first wall  1104 A of the housing  1102  includes one or more access window covers  1114  removably coupled thereto. The access window covers  1114  are configured to cover the access windows  1112 , which prevents access to the internal components of the electromagnetic machine  1100  and protects those components. Generally, each access window  1112  will have a corresponding access window cover  1114 . The access window covers  1114  can be coupled to the first wall  1104 A of the housing  1102  in any suitable fashion, such as with screws, bolts, clips, etc. During operation of the electromagnetic machine  1100 , each access window cover  1114  is coupled to the first wall  1104 A of the housing  1102  such that an individual or any other object cannot contact any internal components that may be rotating, moving, energized, or otherwise in use. When the electromagnetic machine is not in use, the access window covers  1114  can be removed so that the individual can safely access the internal components through the access window  1112 . 
     As shown in  FIG. 9B , an axle  1105  generally extends through the second wall  1104 B and through a fan guard  1119  coupled to the second wall  1104 B. The axle  1105  is coupled to the housing  1102  via one or more bearings or bearing assemblies, which are discussed in more detail herein. The electromagnetic machine  1100  includes a pair of gussets  1107  that are each coupled to both the first wall  1104 A and the base  1108 . The gussets  1107  provide mechanical stability to the electromagnetic machine  1100  during operation, when the electromagnetic machine  1100  experiences a large amount of mechanical stress, for example due to rotation of the axle  1105 . A gusset cover  1109  is coupled to the first wall  1104 , the base  1108 , and each of the gussets  1107 . 
     The housing  1102  can also have a number of air flow apertures defined therein to allow air to flow through the housing  1102  during operation. For example, the cover panel  1106  can include air flow apertures  1118 . The air flow can help to cool the internal components of the electromagnetic machine  1100  and keep the temperature of the machine within an acceptable range, thus allowing the electromagnetic machine  1100  to be used in a wider variety of conditions and scenarios. The first wall  1104 A, second wall  1104 B, cover panel  1106 , base  1108 , and internal components can be mechanically coupled by a variety of means, such as screws, nails, bolts, pins, clips, welds, or any other suitable coupling mechanism. In an implementation, the second wall  1104 B is not an independent component of the housing  1102 . Rather, the second wall  1104 B can be a portion of a separate component that is coupled to the electromagnetic machine  1100 , such as a portion of the housing of the prime mover. In a further implementation, the second wall  1104 B of the housing can be an outer housing of the rotor. 
     Exploded views of the electromagnetic machine of  FIG. 9A  and  FIG. 9B  are shown in  FIG. 10A  and  FIG. 10B , respectively. The first wall  1104 A of the housing  1102  is shown with access window covers  1114 A and  1114 B exploded from access windows  1112 A and  1112 B. The internal components of the electromagnetic machine  1100  include a stator assembly  1200  and a rotor assembly  1300 . The stator assembly  1200  is disposed generally between the first wall  1104 A and the rotor assembly  1300 , while the rotor assembly  1300  is disposed generally between the stator assembly  1200  and the second wall  1104 B. 
     The first wall  1104 A defines a first wall opening  1120 A, while the second wall  1104 B defines a second wall opening  1120 B. The stator assembly  1200  defines a stator opening  1216 . The electromagnetic machine  1100  includes a bearing assembly  1400  that is configured to pass through the first wall opening  1120 A and the stator opening  1216 , and non-rotationally couple to both the first wall  1104 A and the stator assembly  1200 . The axle  1105  extends through the bearing assembly  1400  and thus through the first wall  1104  and the stator assembly  1206 . The bearing assembly  1400  supports the axle  1105  while allowing the axle  1105  to rotate relative to the bearing assembly  1400 , the first wall  1104 A, and the stator assembly  1200 . The axle  1105  generally extends through the first wall opening  1120 A and past the first wall  1104 A. However, the gussets  1107  and the gusset cover  1109  generally enclose the end of the axle  1105  that extends past the first wall  1104 A. 
     In an implementation of the electromagnetic machine  1100 , the stator assembly  1200  includes one or more coil modules, which include coils of wire that are wrapped around a permeable core of magnetic material, while the rotor assembly  1300  includes one or more magnets configured to be disposed adjacent to the coils of wire when the electromagnetic machine  1100  is in use. In another implementation, the stator assembly  1200  includes the magnets while the rotor assembly  1300  contains the coil modules. As will be described in more detail herein, the rotor assembly  1300  generally defines a channel around which the magnets are disposed. During operation of the electromagnetic machine  1100 , the coil modules that are attached to the stator assembly  1200  are disposed within the channel defined by the rotor assembly  1300 . 
     The first wall  1104 A of the housing  1102  includes one or more housing locking apertures  1122  defined therein. Similarly, the stator assembly  1200  includes one or more stator assembly locking apertures  1222  defined therein. Each of the housing locking apertures  1122  and the stator assembly locking apertures  1222  are sized such that a locking mechanism may be removably inserted therethrough to prevent the rotation of the stator assembly about the axle via the bearing assembly  1400 . During operation of the electromagnetic machine  1100 , the stator assembly  1200  can be locked into place to prevent any unnecessary or undesired movement. When the electromagnetic machine  1100  needs to be serviced, the locking mechanism can be removed from the housing locking apertures  1122  and the stator assembly locking apertures  1222  to allow the stator assembly  1200  to be rotated until a desired portion of the stator assembly  1200  is accessible through the access windows. The locking mechanism can be, for example, a bolt, a pin, a spring-loaded pin, or a linearly actuated pin. In other implementations, locking mechanisms that do not utilize apertures defined in the housing and the stator could be used, such as clips or fasteners. While the figures show potential locations of the housing locking apertures  1122  and the stator assembly locking apertures  1222 , these apertures can be defined anywhere on the electromagnetic machine  1100  as long as a locking mechanism can be inserted through both apertures to thereby prevent rotation of the stator assembly relative to the housing. 
       FIGS. 11A and 11B  shows perspective view of the axle  1105  mounted to the bearing assembly  1400 .  FIG. 11C  shows an exploded perspective view of the axle  1105  and the bearing assembly  1400 .  FIG. 11D  shows a cross-sectional view of the axle  1105  and the bearing assembly  1400 . The bearing assembly  1400  is configured to be disposed partially in the first opening  1120 A of the first wall  1104 A and the stator opening  1216  of the stator assembly  1200 . The bearing assembly  1400  has a generally cylindrical body that includes body portion  1402 A and body portion  1402 B. The bearing assembly  1400  also includes a circumferentially extending flange  1404  separating body portion  1402 A and  1402 B. 
     When the electromagnetic machine  1100  is fully assembled, the bearing assembly  1400  is positioned such that the body portion  1402 B is disposed in the opening  1120 A of the first wall  1104 A. The flange  1404  will be positioned within the interior of the electromagnetic machine  1100 . The bearing assembly  1400  also extends through the stator assembly  1200  such that at least a portion of the body portion  1402 A is disposed in the opening  1216  of the stator assembly  1200 . Thus, the flange  1404  of the bearing assembly  1400  is sandwiched between the first wall  1104 A and the stator assembly  1200 . The flange  1404  includes a number of apertures  1406  extending axially through the flange  1404 . The apertures  1406  are configured to receive fasteners that extend through the first wall  1104 A to non-rotationally secure the first wall  1104 A and the bearing assembly  1400 . In some implementations, the fasteners also extend through the stator assembly  1200  to non-rotationally secure the stator assembly  1200  to the first wall  1104 A and the bearing assembly  1400 . 
     The bearing assembly  1400  and axle  1105  generally include a first bearing  1408 A and a second bearing  1408 B that couple the axle  1105  to the bearing assembly  1400 . The first bearing  1408 A is disposed within the bearing assembly  1400  and is generally coincident with body portion  1402 B of the bearing assembly  1400 . Thus, the first bearing  1408 A is also generally coincident with the first opening  1120 A of the first wall  1104 A. The second bearing  1408 B is disposed at an end of the bearing assembly  1400  opposite the first bearing  1408 A, and is generally positioned such that it is disposed within the interior of the electromagnetic machine  1100 . When the bearing assembly  1400  and the axle  1105  are fully assembled, the axle  1105  is coupled to the bearing assembly  1400  via the first bearing  1408 A and the second bearing  1408 B. The axle  1105  is thus rotatable relative to the bearing assembly  1400 . Because the bearing assembly  1400  is non-rotationally secured to the first wall  1104 A and the stator assembly  1200 , the axle  1105  is also rotatable relative to the first wall  1104 A and the stator assembly  1200 . 
     The first bearing  1408 A is generally coupled to the interior of body portion  1402 B of the bearing assembly  1400  such that when the axle  1105  is removed from the bearing assembly  1400 , the first bearing  1408 A remains disposed within the interior of the bearing assembly  1400 . However, the second bearing  1408 B is generally coupled to the axle  1105  via a friction fit. In this manner, when the axle  1105  is removed from the bearing assembly  1400 , the second bearing  1408 B remains coupled to the axle  1105 . In other implementations however, the first and second bearings  1408 A,  1408 B can be coupled to the bearing assembly  1400  and/or the axle  1105  in any suitable manner. 
     As best shown in  FIG. 11C , the bearing assembly  1400  further includes a spring  1410 , a number of collar components  1412 ,  1414 , and  1416 . The collar components  1412 ,  1414 ,  1416  all thread onto the axle  1105  so as to press the spring  1410  against the first bearing  1408 A. This presses the first bearing  1408 A against an internal shoulder  1418  within the bearing assembly  1400  to thereby hold the first bearing  1408 A in place. The spring  1410  thus preloads the first bearing  1408 A, and removes any radial play in the first bearing  1408 A. Once the axle  1105  is inserted into the bearing assembly  1400 , the second bearing  1408 B is pressed against another internal shoulder  1420  of the bearing assembly  1400 , as well as a shoulder  1422  of the axle  1105 . This assists in preloading the second bearing  1408 B to remove any radial play. 
       FIG. 12A  and  FIG. 12B  illustrate perspective views of the stator assembly  1200 , while  FIG. 12C  and  FIG. 12D  illustrate exploded views of the stator assembly  1200  of  FIG. 12A  and  FIG. 12B , respectively. The stator assembly  1200  generally includes a stator plate  1210 , a circuit board  1230 , and a coil housing  1240  mounted to the stator plate  1210 . The coil housing  1240  includes slots in which the coil modules may be disposed during operation of the electromagnetic machine  1100 . The stator plate  1210  generally includes an inner stator mount  1212 , a circumferentially extending outer stator mount  1214 , and a hub retainer  1217 . The inner stator mount  1212  defines the stator opening  1216 . The hub retainer  1217  is coupled to the inner stator mount  1212  and is generally positioned within the stator opening  1216  of the inner stator mount  1212 . The hub retainer  1217  itself generally defines an opening through which the axle  1105  and the bearing assembly  1400  will be disposed when the electromagnetic machine  1100  is assembled. The bearing assembly  1400  is generally coupled to the inner periphery of the hub retainer  1217  via the fasteners that extend through the apertures  1406  in the flange  1404  of the bearing assembly. When the locking mechanism is removed from the housing locking apertures  1122  and the stator assembly locking apertures  1222 , the hub retainer  1217  retains the stator assembly  1200  in its axial alignment with the axle  1105  and the bearing assembly  1400 . The stator assembly  1200  is thus still able to be rotated about the axle  1105  via the bearings  1408 A,  1408 B of the bearing assembly  1400 . The hub retainer  1217  also assists in maintaining the inner edge of the inner stator mount  1212  in alignment with the flange  1404  of the bearing assembly  1400 . 
     The stator assembly locking apertures  1222  are defined in or coupled to the outer stator mount  1214 . In some implementations, the inner stator mount  1212  receives the fasteners that extend through the first wall  1104 A and the flange  1404  of the bearing assembly  1400 . In other implementations, other components of the stator assembly  1200  receive the fasteners. 
     The stator plate  1210  further includes a circumferentially extending alignment plate  1220  ( FIGS. 12C and 12D ) that is disposed at least partially between the inner stator mount  1212  and the outer stator mount  1214 . The alignment plate  1220  has a generally circular shape with an opening defined in the center thereof, and thus has an inner periphery and an outer periphery. The inner periphery of the alignment plate  1220  overlaps with and is coupled to a periphery of the inner stator mount  1212 , while the outer periphery of the alignment plate  1220  overlaps with and is coupled to an inner periphery of the outer stator mount  1214 . In an implementation, the alignment plate  1220  is modular and is formed from a plurality of separate and distinct alignment plate sections that are disposed about the inner stator mount  1212 . In another implementation, the alignment plate  1220  is a single unitary piece. 
     The circuit board  1230  is coupled to and generally overlaps with the alignment plate  1220 . Similar to the alignment plate  1220 , the circuit board  1230  can be modular and thus can be formed from a plurality of separate and distinct circuit board sections. Each of the circuit board sections can correspond to one of the alignment plate sections. The circuit board sections can be electrically connected together by one or more circuit board jumpers  1232 , and are generally attached to the alignment plate sections via fasteners, such as screws, rods, pins, etc. In another implementation, the circuit board  1230  is a single unitary piece. The electrical connections between the circuit board  230  can be designed in any manner required for the specific application of the electromagnetic machine  100 , and may be replaced from time to time as application requirements change. As will be described in more detail herein, the alignment plate  1220  is used to align the electrical leads from the coil modules with the circuit board sections, and to assist in maintaining contact between the electrical leads from the coil modules and the circuit board  1230 . 
     The inner stator mount  1212  includes a plurality of flanges  1213  extending from the outer periphery of the inner stator mount  1212  towards the coil housing  1240 . Similarly, the outer stator mount  1214  includes a plurality of flanges  1215  extending from the inner periphery of the outer stator mount  1214  towards the coil housing  1240 . The flanges  1213  are configured to be coupled to an inner periphery of the coil housing  1240 , while the flanges  1215  are configured to be coupled to an outer periphery of the coil housing  1240 , as will be described in further detail herein. 
     The arrangement between the coil modules, the circuit board, and the alignment plate is illustrated in  FIG. 13A .  FIG. 13A  illustrates three portions  1201 A,  1201 B, and  1201 C of the stator assembly  1200 . The first portion  1201 A includes circuit board section  1231  and an underlying alignment plate section underneath the circuit board section  1231 . The second portion  1201 B shows the circuit board section removed, leaving only the underlying alignment plate section  1221 . The third portion  1201 C shows both the circuit board section and the underlying alignment plate section removed. 
     As shown, each of the plurality of coil modules includes two coil leads  1225 A and  1225 B extending out of the coil housing toward the alignment plate and the circuit board. Each coil lead  1225 A,  1225 B is generally wrapped around a respective coil nut  1229 A,  1229 B. The coil nuts  1229 A,  1229 B can be made of a conductive material or a non-conductive material. The coil nuts  1229 A,  1229 B are sized so as to fit through alignment plate coil lead apertures  1224  that are defined by each alignment plate section. The alignment plate coil lead apertures  1224  generally have a rectangular cross-section. This allows the coil nuts  1229 A,  1229 B to fit into and through the alignment plate coil lead apertures  1224  but restricts the coil nuts  1229 A,  1229 B from rotating within the alignment plate coil lead apertures  1224 . 
     Because the coil leads  1225 A,  1225 B are wrapped around the coil nuts  1229 A,  1229 B, terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1226 B will extend through the alignment plate coil lead apertures  1224 , as shown in section  1201 B. As shown with respect to the first portion  1201 A, the circuit board sections are disposed directly on top of the alignment plate sections, thus sandwiching the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B between the coil nuts  1229 A,  1229 B and the circuit board section. In this configuration, the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B contact the circuit board at respective circuit board contact areas, thus electrically connecting the coil modules to the circuit boards. The alignment plate sections help to align the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B with the appropriate circuit board contact area. The pressure on the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B also helps to maintain the electrical connection between the coil modules and the circuit board. 
     In an implementation, each circuit board section has a plurality of circuit board coil lead apertures  1227  defined therein that correspond to the plurality of the alignment plate coil lead apertures  1224 . In this implementation, an alignment component  1235 , such as a screw, bolt, pin, clamp, etc., can be inserted through the circuit board coil lead apertures  1227  and the alignment plate coil lead apertures  1224 . The alignment components  1235  then pass through apertures defined in the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B, and insert into cavities defined in the coil nuts  1229 A,  1229 B. The alignment components  1235  thus secure the coil leads  1225 A,  1225 B in place. In some implementations, the alignment components  1235  are screws that have a head and a threaded body. The heads of the screws are generally larger than the circuit board coil lead apertures  1227 , while the threaded bodies of the screws are smaller than the circuit board coil lead apertures  1227 . 
     In some implementations, the cavities defined in the coil nuts  1229 A,  1229 B are threaded such that the screws can be fastened to the coil nuts  1229 A,  1229 B. As the screws are tightened, the terminating ends  1226 A,  1226 B are sandwiched between the circuit board sections and the coil nuts  1229 A,  1229 B. This serves both to couple the circuit board section and the alignment plate section together, and to assist in completing and maintaining the electrical connection between the coil leads  225 A,  225 B and the circuit board section. In some implementations, the alignment components  1235  can be electrically conductive and can be configured to contact both the circuit board when disposed through the circuit board coil lead apertures, and the terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B, thus helping to ensure that the coil leads  1225 A,  1225 B are electrically connected to the circuit board. 
       FIG. 13B  shows a zoomed-in view of the coil nuts  1229 A,  1229 B of a single coil  1243 . As shown, the two coil leads  1225 A,  122 B extend away from the coil  1243  and wrap around respective coil nuts  1229 A,  1229 B. The terminating ends  1226 A,  1226 B of the coil leads  1225 A,  1225 B face the same direction, and have respective apertures  1233 A,  1233 B defined therein. The apertures  1233 A,  1233 B are aligned with apertures in the coil nuts  1229 A,  1229 B that allow the alignment components  1235  ( FIG. 13A ) to be inserted into the cavities of the coil nuts  1229 A,  1229 B. 
     As can be seen in  FIG. 13B , the coil nuts  1229 A,  1229 B have a generally hexagonal cross-sectional shape. This allows the coil nuts  1229 A,  1229 B to be inserted through the alignment plate coil lead apertures  1224 . However, because the alignment plate coil lead apertures  1224  have a generally rectangular cross-section, the coil nuts  1229 A,  1229 B cannot rotate within the alignment plate coil lead apertures  1224 . The coil nuts  1229 A,  1229 B are also larger than the circuit board coil lead apertures  1227 , thus preventing the coil nuts  1229 A,  1229 B from extending too far out of the alignment plate coil lead apertures  1224  in response to the alignment components  1235  being secured to the coil nuts  1229 A,  1229 B. The coil nuts  1229 A,  1229 B and the alignment plate coil lead apertures  1224  can also have other relative shapes so as to prevent the coil nuts  1229 A,  1229 B from rotating within the alignment plate coil lead apertures  1224 . 
     In some implementations, the coil nuts  1229 A,  1229 B generally have at least one face with a groove  1239 A,  1239 B formed therein. The width of the grooves  1239 A,  1239 B is approximately equal to the width of the coil leads  1225 A,  1226 B, such that the coil leads  1225 A,  1225 B can fit within the grooves  1239 A,  1239 B. This allows the coil leads  1225 A,  1225 B to sit flush with the rest of that face of the coil nuts  1229 A,  1229 B. In this configuration, the alignment plate coil lead apertures  1224  simply need to be large enough to allow the coil nuts  1229 A,  1229 B to pass through, and do not need to provide any extra space for the thickness of the coil leads  1225 A,  1225 B. As can be seen in  FIG. 13B , the coil leads  1225 A,  1225 B are generally folded or bent so as to provide a small amount of slack in the length of the coil leads  1225 A,  1225 B. When the coils  1243  are inserted into the stator assembly  1200  and secured to the circuit board  1230 , the slack in the coil leads  1225 A,  1225 B allows the coil leads  1225 A,  1225 B to stretch slightly, so as to prevent the coil leads  1225 A,  1225 B from breaking or being damaged during the assembling or disassembling of the electromagnetic machine  1100 , and also so as to prevent the coils  1243  from being pulled out of alignment within the coil housing  1240 . 
     Referring now to  FIG. 14A  and  FIG. 14B , the coil housing  1240  includes a variety of different components arranged in a circumferential manner. The coil housing  1240  includes a first coil housing ring  1244  and a second coil housing ring  1246 . The coil housing rings  1244 ,  1246  define the slots into which the coils  1243  and the corresponding permeable coil cores  1251  (see  FIGS. 15A and 15B ) are inserted. The coil housing  1240  further includes a plurality of independent core modules  1248  that are disposed between the first coil housing ring  1244  and the second coil housing ring  1246 . A plurality of first backing components  1253  and a plurality of second backing components  1250  are disposed on a side of the coil housing  1240  opposite the side of the coil housing  1240  where the coils  1243  are inserted. 
     The coil housing  1240  also includes a plurality of stator plate mounting brackets  1242  positioned on the end of the coil housing  1240  where the coils  1243  are inserted, and a plurality of coil housing mounting brackets  1252  positioned on the opposite end of the coil housing  1240 . The coil housing mounting brackets  1252  are positioned between the first and second backing components  1253 ,  1250 . Each of the second backing components  1250  has a groove in which a portion of the coil housing mounting brackets  1252  are configured to seat into, thereby locking the second backing components  1250  into place. 
     Finally, the coil housing  1240  includes a plurality of coil housing mounting components  1254  that are configured to couple together the components of the coil housing  1240 . The coil housing mounting components  1254  generally include an inner set of coil housing mounting components  1254  and an outer set of coil housing mounting components  1254 . Each coil housing mounting component  1254  generally extends (i) from the stator plate mounting brackets  1242 , (ii) through the first coil housing ring  1244 , the independent core modules  1248 , the second coil housing ring  1246 , and the first backing components  1253  and to (iii) the coil housing mounting brackets  1252 . The coil housing mounting components  1254  can be bolts, pins, screw, etc., and are configured to lock into place once placed through all of the necessary components. The coil housing mounting components  1254  thus provide the tension maintaining all of the components of the coil housing  1240  in place. Generally, the inner set of coil housing mounting components  1254  extends through an inner periphery of the components of the coil housing  1240 , while the outer set of coil housing mounting components  1254  extends through an outer periphery of the components of the coil housing  1240 . 
     A portion of the coil housing mounting components  1254  are also configured to couple the coil housing  1240  to the inner stator mount  1212  and the outer stator mount  1214 . As shown in  FIGS. 14A and 14B , the stator plate mounting brackets  1242  are arranged circumferentially about the coil housing  1240 . However, in certain positions around this circumferential arrangement, some of the stator plate mounting brackets  1242  are missing, leaving gaps between adjacent stator plate mounting brackets  1242 . These gaps are aligned with the flanges  1213  of the inner stator mount  1212  and the flanges  1215  of the outer stator mount  1214 . The inner coil housing mounting components  1254  that extend through the coil housing  1240  at the circumferential locations corresponding to missing stator plate mounting brackets  1242  instead couple to the flanges  1213  of the inner stator mount  1212 . The outer coil housing mounting components  1254  that extend through the coil housing  1240  at the circumferential locations corresponding to the missing stator plate mounting brackets  1242  instead couple to the flanges  1215  of the outer stator mount  1214 . Because these coil housing mounting components  1254  still extend through the rest of the components of the coil housing  1240 , the coil housing  1240  is thereby coupled to both the inner stator mount  1212  and the outer stator mount  1214 . In some implementations, the coil housing  1240  does not contain any stator plate mounting brackets  1242 , and any of the coil housing mounting components  1253  attach only to the flanges  1213  of the inner stator mount  1212  and flanges  1215  of the outer stator mount  1214 . 
     Detailed views of the coil housing  1240  are illustrated in  FIG. 15A  and  FIG. 15B . Various portions of the components of the coil housing  1240  have been removed from the figures to show internal details. As shown, each coil  1243  includes a corresponding permeable coil core  1251 . In this manner, each coil  1243  is wound around its own individual core  1251 . The coil cores  1251  can be made of a ferromagnetic material, such as laminated electrical steel. In some implementations, each individual core  1251  is configured to be disposed completely within its corresponding coil  1243 . In other implementations, each individual core  1251  is disposed partially within its corresponding coil  1243  such that at least a portion of each core  1251  extends outside of the bounds of its corresponding coil  1243 . In some implementations, each coil  1243  can have a generally rectangular shape that includes a first side surface  1260 A, a second side surface  1260 B, and a third side surface  1260 C. The cores  1251  can have a similar generally rectangular shape. Other shapes for the coils  1243  and the cores  1251  are also contemplated. 
     The coil housing  1240  includes the first coil housing ring  1244  and the second coil housing ring  1246 . Each of these coil housing rings can be made of a ferromagnetic material such as laminated electrical steel. Both of the coil housing rings  1244 ,  1246  are generally circular shaped and have an inner periphery and an outer periphery. The first coil housing ring  1244  includes a plurality of repeating columns  1245 A connecting the inner periphery and the outer periphery of the first coil housing ring  1244 . The first coil housing ring also defines a plurality of gaps  1245 B. Each gap  1245 B is defined between adjacent columns  1245 A and is sized such that the coils fit through the gaps  1245 B. 
     Similarly, the second coil housing ring  1246  also includes a plurality of repeating columns  1247 A connecting the inner periphery and the outer periphery of the second coil housing ring  1246 . The second coil housing ring  1246  defines a plurality of gaps  1247 B. Each gap  1247 B is defined between adjacent columns  1247 A and is sized such that the coils  1243  fit through the gaps  1247 B. The gaps  1245 B defined in the first coil housing ring  1244  and the gaps  1247 B defined in second coil housing ring  1246  overlap, and thus the first coil housing ring  1244  and the second coil housing ring  1246 , when assembled as part of the coil housing  1240 , define the plurality of slots  1241  which are sized to receive a plurality of coils  1243 , each slot  1241  receiving a single coil  1243 . 
       FIGS. 15A and 15B  show two of the independent core modules  1248  that are disposed between the first coil housing ring  1244  and the second coil housing ring  1246 . The independent core modules  1248  can be made of a ferromagnetic material similar to the other components of the coil housing  1240 , such as laminated electrical steel. The independent core modules  1248  are disposed between the first coil housing ring  1244  and the second coil housing ring  1246  such that an end of each of the independent core modules  1248  adjacent the first coil housing ring  1244  abuts one of the columns  1245 A, while an opposing end of each of the independent core modules  1248  adjacent the second coil housing ring  1246  abuts a corresponding one of the columns  1247 A. The independent core modules  1248  are disposed in areas between the first coil housing ring  1244  and the second coil housing ring  1246  that would otherwise be empty space between adjacent coils  1243 . Thus, when the coil  1243  and corresponding core  1251  of  FIGS. 15A and 15B  is received within the slots  1241  of the coil housing  1240 , the coil  1243  and corresponding core  1251  will be disposed between the pair of independent core modules  1248  that are illustrated in  FIGS. 15A and 15B . When the electromagnetic machine  1100  is fully assembled, each coil  1243 -core  1251  combination will be disposed between a pair of adjacent independent core modules  1248 . 
     In some implementations, each of the independent core modules  1248  includes an outer radial lip  1257  and in inner radial lip  1258 . The outer radial lip  1257  of each of the independent core modules  1248  is configured to extend over the first side surface  1260 A of a corresponding one of the coils  1243 . Similarly, the inner radial lip  1258  of each of the independent core modules  1248  is configured to extend over the second side surface  1260 B of a corresponding one of the coils  1243 . The presence of the radial lips  1257 ,  1258  reduces or eliminates any gaps between the side surfaces  1260 A,  1260 B of the coils  1243  and the radial magnets of the electromagnetic machine  1100 . This helps to channel magnetic flux from the radial magnets to the coils  1243  more efficiently. 
     The plurality of first backing components  1253 , the plurality of second backing components  1250 , and the plurality of coil housing mounting brackets  1252  are disposed on a side of the coil housing  1240  opposing the stator plate  1210 . The first and second backing components  1253  and  1250  can be made of a ferromagnetic material similar to other components of the coil housing  1240 , such as laminated electrical steel. Each of the first and second backing components  1253  and  1250  has a groove defined therein that is configured to mate with an edge of a corresponding coil housing mounting bracket  252  such that the backing components  250  and the coil housing mounting brackets  252  interlock with each other. Each of the second backing components  1250  includes an axial lip  1259  that is configured to extend over the third side surface  1260 C of a corresponding one of the coils  1243 . The axial lips  1259  of the backing components  1250  reduce or eliminate any gaps between the third side surface  1260 C and the axial magnets of the electromagnetic machine  1100 . This helps to channel magnetic flux from the axial magnets to the coils  1243  more efficiently. 
     The ferromagnetic components of the coil housing  1240  can include the first coil housing ring  1244 , the second coil housing ring  1246 , the independent core modules  1248 , the first backing components  1253 , the second backing components  1250 , and the coil cores  1251 . All of the components of the coil housing  1240  can be high permeability materials with low hysteresis and related core losses, which may be utilized to maximize the strength of the magnetic field in the region of the coil housing  1240 . 
     The combination of the access windows defined in the housing of the electromagnetic machine, the stator being coupled to the axle via the bearing assembly, the circuit board and alignment plate being formed in sections, and the coil modules being housed in individual slots within the coil housing allows the electromagnetic machine  1100  to be a modular machine where individual coil modules can be replaced, repaired, or upgraded without having to take apart or dissemble the entire machine. The circuit board sections can be easily swapped out to wire the coil modules in different arrangements, thus allowing the electromagnetic machine to be used in a wide variety of applications. By providing the access windows in the housing, an individual is able to access the internal components of the electromagnetic machine without removing the entirety of the housing. This has the added benefit of maintaining alignment between the rotor and the stator. Moreover, the coil modules are simply inserted into individual slots defined in the coil housing for operation, and thus are easy to remove from the electromagnetic machine. 
     Once the access window cover has been removed, the individual can deactivate the locking mechanism to allow the stator assembly to rotate about the bearing assembly relative to the housing. The individual can then rotate the stator assembly until the circuit board section or coil modules that needs to be addressed is accessible through the window. Because the circuit board can be formed in separate and distinct sections, only a single circuit board section needs to be removed to access any of the coil modules underneath. Thus, rather than having to electrically disconnect all of the coils of the electromagnetic machine to replace a single coil module, the individual only has to electrically disconnect the coil modules connected to the single circuit board segment. In an implementation, the electromagnetic machine includes seventy-two coil modules circumferentially arranged in the stator and twelve circuit board sections. Thus, each circuit board section is directly electrically connected to only six coils, which reduces the number of coils that need to be detached to remove a circuit board segment from seventy-two coils to six coils. In other implementations, the electromagnetic machine includes 12, 36, 144, or any other number of coil modules, and 3, 4, 6, 24, or any other number of circuit board sections. 
       FIG. 16A  and  FIG. 16B  illustrate perspective views of the rotor assembly  1300 , while  FIG. 16C  illustrates a perspective view of a rotor housing  1302  of the rotor assembly  1300 .  FIG. 16D  illustrates a cross-sectional view along cross-sectional line  16 D indicated in  FIG. 16C . As shown, the rotor assembly  1300  houses the magnets of the electromagnetic machine  1100 . The rotor assembly includes a rotor housing  1302  that is coupled to the axle such that rotation of the axle causes the rotor housing  1302  to rotate. Conversely, rotation of the rotor housing  1302  causes the axle to rotate. In an implementation, the axle has a rotation locking feature that is configured to non-rotationally mate with a rotation locking feature of the rotor housing  1302  to prevent relative rotation between the axle and the rotor housing  1302 . The rotation locking feature of the axle can be a protrusion, ring, nub, or other structural feature, while the rotation locking feature of the rotor housing  1302  can be a groove or aperture defined in the rotor housing  1302 , or vice versa. In another implementation, the axle is fixedly coupled to the rotor housing  302  as a single integral piece. 
     The rotor housing  1302  includes a back portion  1304 , an outer ring portion  1306 , and an inner ring portion  1308 . The outer ring portion  1306  and the inner ring portion  1308  are arranged generally concentrically about the axle, and extend away from a surface  1310  of the back portion  1304  generally in a first direction. In an implementation, the outer ring portion  1306  and the inner ring portion  1308  are parallel. In other implementations, the outer ring portion  1306  and the inner ring portion  1308  can be disposed at angles with respect to each other, or with respect to the back portion  1304 . A circumferentially extending channel  1312  is defined between the outer ring portion  1306  and the inner ring portion  1308 . The channel  1312  is generally defined by a first surface, a second surface, and a third surface. The first surface is formed from an inner surface  1314  of the outer ring portion  1306  of the rotor housing  1302 . The second surface is formed from an outer surface  1316  of the inner ring portion  1308  of the rotor housing  1302 . The third surface is formed from the portion of the surface  1310  of the back portion  1304  that is disposed between the outer ring portion  1306  and the inner ring portion  1308 . Generally, the back portion  1304 , the outer ring portion  1306 , and the inner ring portion  1308  are all formed as a single unitary piece. 
     Generally, the inner surface  1314  of the outer ring portion  1306  and the outer surface  1316  of the inner ring portion  1308  are parallel to each other and to a longitudinal axis of the axle. Thus, the first surface and the second surface defined by the channel  1312  are generally parallel to each other. The surface  1310  of the back portion  1304  is generally orthogonal to both the inner surface  1314  of the outer ring portion  1306  and the outer surface  1316  of the inner ring portion  1308 . Thus, the third surface defined by the channel  1312  is generally orthogonal to both the first surface and the second surface such that the channel  1312  has a U-shaped cross section. Other cross-sectional shapes of the channel  1312  are also contemplated. 
     The rotor assembly  1300  further includes a plurality of magnets disposed within the circumferentially extending channel  1312 . The plurality of magnets is disposed in circumferentially extending groups of magnets. As shown in  FIG. 16A , the plurality of magnets includes outer radial magnets  1318  coupled to the inner surface  1314  of the outer ring portion  1306  of the rotor housing  1302 . Each adjacent pair of outer radial magnets  1318  can be separated by an outer radial spacer  1320 . The outer radial magnets  1318  and the outer radial spacers  1320  are disposed along the circumferentially extending channel  1312  such that the outer radial magnets  1318  and the outer radial spacers  1320  generally encircle the axle. 
     The plurality of magnets further includes inner radial magnets  1322  coupled to the outer surface  1316  of the inner ring portion  1308  of the rotor housing  1302 . Each adjacent pair of inner radial magnets  1322  can be separated by an inner radial spacer  1324 . The inner radial magnets  1322  and the inner radial spacers  1324  are disposed along the circumferentially extending channel  1312  such that the inner radial magnets  1322  and the inner radial spacers  1324  generally encircle the axle. 
     Finally, the plurality of magnets includes axial magnets  1326  coupled to the surface  1310  ( FIG. 16C ) of the back portion  1304  of the rotor housing  1302  between the inner ring portion  1308  and the outer ring portion  1306 . Like outer radial magnets  1318  and inner radial magnets  1322 , the axial magnets  1326  in the axial group of magnets  1326  are disposed along the circumferentially extending channel  1312  such that the axial magnets  1326  generally encircle the axle or the radius of the inner ring portion  1308  of the rotor housing  1302 . 
     Each of the magnets  1318 ,  1322 , and  1326  may be coupled to the respective surfaces of the rotor housing  1302  in a variety of ways. For example, an adhesive layer can be disposed between the magnets and the surface of the rotor housing  1302  to thereby adhesively couple the magnets to the surface of the rotor housing  1302 . The magnets can also be screwed into the surface of the rotor housing  1302 . In some implementations, the rotor housing  1302  can include a retention component that assists in coupling any of the magnets to the rotor housing  1302 . The retention component could include one or more clamps or pins that are designed to retain any of the magnets to the corresponding surface. The retention component could also include one or more retaining rings. Generally, the retaining rings are disposed in the channel  1312  and are formed to fit around at least a portion of the circumference of the channel  1312 . In this manner, the radius of curvature of the retaining ring is generally equal to the radius of the outer ring portion  1306  of the rotor housing  1302 , or the radius of the inner ring portion  1308  of the rotor housing  1302 . 
     In the implementation shown in  FIG. 16B , the rotor assembly  1300  includes a first retention ring that is formed from first retention ring components  1328 A-D. The first retention ring components  1328 A-D are disposed at an edge of the outer ring portion  1306  that is spaced apart from the back portion  1304  of the rotor housing  1302 . First retention ring components  1328 A-D can be coupled to the rotor housing  1302  via screws, adhesive, or any suitable mechanism, and is configured to help hold one edge of each of the outer radial magnets  1318  in place. Similarly, a second retention ring that is formed from second retention ring components  1330 A-E can be disposed at an edge of the outer ring portion  1306  that abuts the back portion  1304  of the rotor housing  1302 . The second retention ring components  1330 A-D help to hold the opposite edge of each of the outer radial magnets  1318  in place. The rotor assembly  1300  can further include a third retention ring formed from third retention ring components  1332 A-D and a fourth retention ring  1334  that help to hold each of the inner radial magnets  1322  in place. In other implementations, any or all of the retention rings can be formed as single unitary pieces, or can be formed as multiple components. In other implementations, any of the retention rings can instead be retentions pins, which can include or be a dowel. 
     Each of the outer radial magnets  1318 , inner radial magnets  1322 , and axial magnets  1326  can be a dipole magnet with a north pole and a south pole. Each pole of each of the magnets has a corresponding pole face, which is the terminating surface of the magnet corresponding to a respective pole. Thus, opposing surfaces of each of the outer radial magnets  1318 , inner radial magnets  1322 , and axial magnets  1326  are the two pole faces of each magnet. In the rotor assembly  1300 , one pole face of each of the magnets faces towards the respective surface defined by the channel to which the magnets are coupled. When the magnets are mounted to the rotor housing  1302 , this pole face of each magnet facing the surface defined by the channel abuts and/or contacts the channel. The other opposing pole face of each of the magnets faces away from the respective surface of the channel to which the magnets are coupled. Thus, for each of the outer radial magnets  1318 , one of the pole faces abuts the inner surface  1314  of the outer ring portion  1306  of the rotor housing  1302 , while the other pole face of each of the outer radial magnets  1318  faces away from the inner surface  1314  of the outer ring portion  1306  of the rotor housing  1302 . For each inner radial magnet  1322 , one of the pole faces abuts the outer surface  1316  of the inner ring portion  1308  of rotor housing  1302 , while the other pole face of each of the inner radial magnets  1322  faces away from the outer surface  1316  of the inner ring portion  1308  of rotor housing  1302 . For each axial magnet  1326 , one pole face abuts the surface  1310  of the back portion  1304  of the rotor housing  1302  between the outer ring portion  1306  and the inner ring portion  1308 , while the other pole face of each of the axial magnets  1326  faces away from the surface  1310  of the back portion  1304  of the rotor housing  1302  between the outer ring portion  1306  and the inner ring portion  1308 . 
     The groups of magnets  1318 ,  1322 ,  1326  disposed within the channel  1312  of the rotor housing  1302  can be categorized into sets of magnets. Each set of magnets contains one outer radial magnet  1318 , one inner radial magnet  1322 , and one axial magnet  1326 . The three magnets in each set of magnets can be located at identical circumferential positions within the channel  1312  relative to the axle. Thus, a magnet set containing the outer radial magnet  1318  located at the three o&#39;clock position within the channel  1312  relative to the orientation of the channel  1312  in  FIG. 16C  would also contain the inner radial magnet  1322  and the axial magnet  1326  that are both also located at the three o&#39;clock position. In an exemplary implementation of the electromagnetic machine  1100 , the rotor assembly  1300  contains twenty-four sets of magnets circumferentially disposed in the channel  1312  about the axle. The magnets in each set of magnets can also be staggered in relation to one another, and can also be oriented at a variety of angles with respect to both the surface the magnet is coupled to and the other surfaces of the rotor housing  1302 . 
     Each magnet in any given set of magnets has an identical pole face abutting the surface of the rotor housing  1302 , as compared to the other magnets in the set. Thus, each magnet in the set of magnets has an identical pole face directed towards the channel  1312  itself. The pole face that is directed towards the channel  1312  in each magnet set alternates for every circumferentially adjacent magnet set. For example, a first magnet set and a second magnet set may be disposed circumferentially adjacent to each other within the channel  1312 . Each magnet in this first magnet set has the same pole face abutting the surface defining the channel. As an example, each of the three magnets in this first magnet set may have the north pole face abutting respective surfaces defining the channel  1312 , and thus will have the south pole face facing towards the channel itself. Each magnet in the circumferentially adjacent second magnet face will then have the south pole face abutting the respective surfaces defining the channel  1312 , and thus will have the north pole face facing towards the channel itself. 
     This arrangement of alternating pole faces for each magnet set continues circumferentially around the channel  1312 . The alternating pole face arrangement of the magnet sets helps to direct the magnetic flux in an alternating and looping fashion through the channel, from the north pole faces to the south pole faces. With the exception of a small air gap region, when the machine is in operation, most of the channel  1312  is occupied by the stator assembly  1200 , in particular the coil housing  1240  which includes the coils  1243  and coil cores  1251 . The high permeability of the materials in the coil housing  1240  increases the magnetic field in the channel, and is designed to channel the flux most efficiently through the coils  1243 . 
     In any given set of magnets, one of the pole faces of the outer radial magnet will face toward the first side surface  1260 A of the coils  1243 . The pole face of the same polarity of the inner radial magnet in the set of magnets will face toward the second side surface  1260 B of the coils  1243 . The pole face of the same polarity of the axial magnet in the set of magnets will face toward the third side surface  1260 C of the coils  1243 . During operation of the electromagnetic machine  1100 , the rotor will rotate relative to the stator. Thus, the pole faces of the same polarity of the magnets  1318 ,  1322 ,  1326  in a single set of magnets will face toward the respective side surfaces  1260 A,  1260 B,  1260 C of each of the coils  1243  in a rotational sequence as the rotor rotates. An adjacent set of magnets will also have pole faces of the same polarity facing toward the respective side surfaces of the coils, except that the pole face will be of the opposite polarity. Because of the alternating polarity of the pole faces of each set of magnets that faces toward the respective side surfaces of the coils  1243 , the magnetic flux from the magnets is directed through the coils such that the magnetic flux is normal to a plane that is defined by the coils  1243  and/or the cores  1251 . 
     The rotor housing  1302  can include one or more fan blades  1342  coupled thereto. In an implementation, the fan blades  1342  can be coupled to the portion of the surface  1310  of the back portion  1304  that is disposed between the inner ring portion  1306  and the axle  1105 . The fan blades  1342  thus extend outwardly from the surface  1310  generally in the first direction, which is the same as the outer ring portion  1306  and the inner ring portion  1308 . In another implementation, the fan blades  1342  are coupled to an inner surface  1315  of the inner ring portion  1308 , and extend in a radial direction toward the axle. The rotor housing  1302  further includes one or more air flow apertures  1344  defined in the back portion  1304 . During rotation of the rotor assembly  1300 , the rotating fan blades  1342  direct air through the air flow apertures  1344 , thus cooling the internal components of the electromagnetic machine  1100 . 
     A cross-section view of the assembled electromagnetic machine  100  is illustrated in  FIG. 17 . The first wall  1104 A of the housing is shown, along with the connection box  1110 . The axle  1105  is coupled to bearing assembly  1400 . The axle  1105  is thus rotatable relative to the housing and the stator assembly. As the stator assembly and the rotor assembly come together in operation, the coils  1243  and the corresponding cores  1251  are disposed within the U-shaped channel formed by the rotor housing. Finally,  FIG. 17  shows one implementation of a locking mechanism. As can be seen, the locking mechanism includes a locking member  1256  inserted through both the first wall  1104 A of the housing, and the stator assembly. Thus, while the stator assembly may generally be rotatable relative to the bearing assembly  1400 , the locking member  1256  prevents the stator assembly from rotating while the locking member  1256  is activated or engaged. 
       FIG. 17  also shows the first bearing  1408 A and the second bearing  1408 B of the bearing assembly  1400 . As shown, the first bearing  1408 A supports the axle  1105  and is positioned within the first wall  1104 A. The second bearing  1408 B supports the axle  1105  and is positioned within the interior of the electromagnetic machine  1100 . As shown the flange  1404  of the bearing assembly  1400  is positioned between the first wall  1104 A and the stator assembly. Fasteners  1261  extend through the first wall  1104 A and the flange  1404  of the bearing assembly  1400  to thereby non-rotationally lock the bearing assembly  1400  to the first wall  1104 A. Because the axle  1105  is rotationally coupled to the bearing assembly  1400  via the first bearing  1408 A and the second bearing  1408 B, the axle  1105  is able to rotate relative to the first wall  1104 A and the stator assembly. The rotor assembly, which is non-rotationally coupled to the axle  1105 , is thus also able to rotate relative to the first wall  1104 A and the stator assembly. 
     As shown in  FIG. 17 , the outer radial magnets  1318  generally always face toward the first side surface  1260 A of the coils  1243 , on both the coil  1243  on top, and the coil  1243  on the bottom. Similarly, inner radial magnets  1322  always face toward the second side surface  1260 B of the coils  1243 , and the axial magnets  1326  always face toward the third side surface  1260 C of the coils  1243 . 
     Both the design of the rotor housing  1302  as a single unitary piece and the axle  1105  being supported by the bearing assembly  1400  enables a very small air gap to be maintained between the coil housing  1240  and the surface of the magnets within the rotor housing  1302  during operation. Generally, the distance between an outer periphery of the coil housing  1240  and the magnets in the rotor housing  1302  is about 1.2 millimeters. The size of this air gap is inversely proportional to the output power and efficiency of the electromagnetic machine, with smaller air gaps providing stronger magnetic fields in the coil housing  1240  and coil cores  1251 . However, tight mechanical tolerances are required to maintain very small air gaps when the machine is in operation. 
     Due to the modular nature of the coils and the circuit board sections, the electromagnetic machine can be configured in a variety of ways. In an implementation, the coils are configured to provide three-phase power. In this implementation, the coils are separated into three different sets of coils, each set of coils corresponding to one of the power phases. Within each phase, the coils can be further divided into two different subsets of coils. Thus, the set of coils for each power phase can comprise two different subsets of series-wired coils, each subset wired in parallel. Each power phase therefore has a backup group of coils. If one of the coils in one subset of a power phase fails, the other subset of coils in that power phase can still provide the power for that phase, as the subsets are wired in parallel. Any number of subsets are contemplated, such as but not limited to two subsets, three subsets, four subsets, or five or more subsets. In a further implementation, all of the coils for each power phase in a multi-phase system are wired together in series. In another implementation, the coils are wired to provide single phase power. The coils in this implementation can be all be wired in series, or can be divided into two or more subsets of coils wired in series, and the subsets being wired together in parallel. In yet a further implementation, the electromagnetic machine includes seventy-two coil modules wired together to provide three-phase power. The first set of coils for the first power phase includes twenty-four coil modules, the second set of coils for the second power phase includes twenty-four coil modules, and the third set of coils for the third power phase includes twenty-four coil modules. Each set of coils is divided into equal subsets wire in parallel, each subset containing twelve coil modules wired in series. 
     To provide service to the electromagnetic machine described herein, the electromagnetic machine must be disconnected from an external electrical power system. A connected prime mover must be stopped and should be locked out. Once the electromagnetic machine is safely isolated and is not operating, an access window cover can be removed from the housing of the electromagnetic machine to provide access to the stator assembly through the access window. A locking mechanism can be deactivated to allow the stator assembly to be rotated within the housing. In an implementation, the locking mechanism is deactivated by removing a locking member from an aperture defined in the housing and an aperture defined in the stator assembly. The stator assembly is then rotated until a desired portion of a circuit board is accessible through the access window. Any coil modules electrically connected to the circuit board section must be disconnected, and then the circuit board section can be removed. The alignment plate section underneath the circuit board section is also removed to provide access to the coil modules. A desired coil module can be removed from the stator assembly, whether for replacement or repair. The coil module is then inserted back into the stator assembly, and the alignment plate section and circuit board section are then replaced. The new coil module is electrically connected to the circuit board, and the access window cover can then be replaced on the housing. The locking mechanism can then be activated to prevent rotation of the stator assembly relative to the housing. In an implementation, the locking mechanism is activated by inserting a locking member into an aperture defined in the housing and an aperture defined in the stator assembly. 
     While the present disclosure has been described with reference to one or more particular implementations, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present disclosure. Each of these implementations and obvious variations thereof is contemplated as falling within the spirit and scope of the present disclosure. It is also contemplated that additional implementations according to aspects of the present disclosure may combine any number of features from any of the implementations described herein.