Nonmagnetic Inserts Or Air Gaps Patents (Class 310/192)
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Patent number: 11799353Abstract: A denoising optimization method for an AC traction motor by chamfering a stator tooth shoulder includes taking an angular vertex of the stator tooth shoulder as an end point, obtaining two points equidistantly along two sides of a stator tooth shoulder angle from the end point; and using the two points as tangent points D1 and D2 of the inscribed arc; making the inscribed arc of the tooth shoulder angle through the two tangent points D1 and D2, cutting off the tooth shoulder angle along the inscribed arc, and adjusting an oblique height HS1 of a stator tooth pole shoe. The invention obtains optimal values of a chamfering size and oblique height of a stator tooth slot pole shoe by adjusting the oblique height of the stator tooth pole shoe and adopting a particle swarm optimization algorithm.Type: GrantFiled: March 25, 2021Date of Patent: October 24, 2023Assignee: HUNAN UNIVERSITY OF SCIENCE AND TECHNOLOGYInventors: Xiaoping Zhang, Donghao Liu, Bo Fu
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Patent number: 10461595Abstract: A rotor assembly for an electric machine includes a core having at least one post and a cap wherein electrical windings are wound about the rotor assembly to define a pole. The rotation of the rotor and rotor pole relative to a stator generates a current supplied from the electric machine to a power consuming device.Type: GrantFiled: November 24, 2014Date of Patent: October 29, 2019Assignee: GE Aviation Systems LLCInventors: Joseph Kenneth Teter, James Patrick Mahle, Winfred Dwight Koontz, Jr., David George Kloos
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Patent number: 10432061Abstract: An annular rotor for a flywheel, the rotor comprising a tow comprising a matrix of fibres wound about an axis and arranged in layers comprising a gap between adjacent tow windings, wherein the winding angle between a normal to the axis and the tow is less than 3.5° and the matrix further comprises magnetic particles of a size less than the critical flaw size of the tow.Type: GrantFiled: January 22, 2015Date of Patent: October 1, 2019Assignee: GKN HYBRID POWER LIMITEDInventor: Rick Townend
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Patent number: 10033236Abstract: In one embodiment, a generator or an alternating current (AC) motor includes a stator and a rotor. The rotor is configured to rotate at least partially within the stator or around the stator and is separated from the stator by a gap having a partial vacuum. The rotor includes a shaft configured to permit a flow of coolant and a plurality of microchannels formed within the rotor. The microchannels are fluidly coupled to the shaft and are configured to permit the coolant to pass from the shaft through at least a portion of the rotor in order to provide cooling for the rotor.Type: GrantFiled: July 20, 2015Date of Patent: July 24, 2018Assignee: Lockheed Martin CorporationInventors: Kurt M. Chankaya, Arthur Philip Schuetze
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Patent number: 9812909Abstract: A method and apparatus for reducing or eliminating the effects of torque ripple and cogging torque and otherwise improving performance in an electromechanical machine such as a motor or generator. The rotor and/or stator is conceptually sectionalized and the sections spaced apart by amount sufficient to alleviate deleterious aspects of cogging torque and torque ripple. Positioning of the stator teeth or rotor magnets is determined based on the calculated spacing. Conceptual sections may be formed as physically individual segments. Unwound teeth may be disposed in end spaces between sections occupying less than the entire area of the end space.Type: GrantFiled: December 10, 2014Date of Patent: November 7, 2017Assignee: WEG Electric CorpInventors: Jeffrey K. Petter, Hector Hurtado
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Patent number: 9136735Abstract: In a rotary electric machine laminated core, a rotating shaft portion is disposed closer to an outer circumferential surface than an inner circumferential surface of a back yoke portion. A notch portion is disposed on at least one of first and second end portions of the back yoke portion so as to form a gap between a vicinity of the rotating shaft portion of a projecting portion and a recess portion when core segments are arranged in an annular shape or a circular arc shape. The first end portion and the second end portion of the back yoke portion are configured such that a predetermined gap that connects from the outer circumferential side to the inner circumferential side is formed between adjacent projecting portions and recess portions when the core segments are expanded rectilinearly such that magnetic pole tooth portions are parallel to each other.Type: GrantFiled: April 8, 2010Date of Patent: September 15, 2015Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Akira Hashimoto, Yuji Nakahara, Hiroyuki Akita, Takanori Ichikawa
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Patent number: 8912697Abstract: A vacuum actuator includes a vacuum partition wall, the interior of which can be evacuated to a vacuum, a rotor supported by the vacuum partition wall to be free to rotate, a permanent magnet provided on the outer peripheral surface of the rotor, a coil opposed to the permanent magnet, and a stator provided with the coil. The stator and the vacuum partition wall are formed integrally with each other.Type: GrantFiled: December 21, 2010Date of Patent: December 16, 2014Assignee: Canon Anelva CorporationInventors: Kazuhito Watanabe, Yukihito Tashiro, Naoyuki Nozawa, Daisuke Kobinata, Hideo Mano
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Patent number: 8604739Abstract: A controller for an axial gap-type motor (3) comprises a rotor (11) having a permanent magnet and a first stator (12a) and a second stator (12b) opposed to each other with the rotor (11) interposed therebetween in the axial direction of revolution of the rotor (11). The controller further includes an electrification control portion which supplies a torque current (Iq) for generating a magnetic field to revolve the rotor (11) to an armature winding (13a) of the first stator (12a) and supplies a field current (+Id) for reinforcing the magnetic flux by the permanent magnet of the rotor (11) or a field current (?Id) for weakening the magnetic flux to an armature winding (13b) of the second stator (12b). Consequently, the controllable range of the motor is increased and the axial gap-type motor can be operated at higher velocity and higher torque.Type: GrantFiled: February 26, 2008Date of Patent: December 10, 2013Assignee: Honda Motor Co., Ltd.Inventor: Hirofumi Atarashi
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Patent number: 8531076Abstract: A stator for an electric motor includes first and second rows of conductors arranged concentrically around an axis inside a steel core. Each conductor includes a linking end. The stator also includes a first dielectric shim ring arranged between the two rows of conductors. Each conductor of the first row is bent in either a clockwise or a counter-clockwise direction relative to the axis and each conductor of the second row is bent in the opposite direction. The linking end of each conductor of the first row is attached to the linking end of an adjacent conductor of the second row after the conductors are bent. The first shim ring separates the first and second rows of conductors when the conductors are being bent, and is also at least partially disposed between the first and second rows of conductors when the linking ends are being attached.Type: GrantFiled: May 17, 2011Date of Patent: September 10, 2013Assignee: GM Global Technology Operations LLCInventors: Sara A. Stabenow, Stephen R. Smith, Edward Panozzo, David F. Titmuss
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Patent number: 8519590Abstract: A magneto generator can be made small in size and light in weight, and improved in power generation efficiency. The magneto generator includes an iron core having an iron core main body and a plurality of teeth (9) radially extending from the iron core main body, and an armature having a first three-phase winding (14) and a second three-phase winding (15) comprising winding portions (18u, 18v, 18w, 19a, 19b and 19c) of individual phases wound around the stator core. The individual first and second three-phase windings (14, 15) have the winding portions (18u, 18v, 18w, 19a, 19b and 19c) constructed by concentratedly winding conductors around the individual teeth (9), respectively, while skipping every predetermined number of teeth (9), and are wound in a state divided into an inner layer side and an outer layer side, respectively.Type: GrantFiled: June 19, 2007Date of Patent: August 27, 2013Assignee: Mitsubishi Electric CorporationInventor: Shinji Baba
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Patent number: 8405258Abstract: A machine tool with a generator for generating electrical power is disclosed. The generator has a stator with a coil and a rotor with a magnet. The rotor is capable of moving relative to the stator. An air gap is formed between the rotor and the stator. The stator and the rotor comprise a material with a relative permeability greater than the relative permeability of air and are arranged in such a way that magnetic lines of force of the magnet are guided in a targeted manner with respect to the coil. The air gap between the stator and the rotor is configured in such a way that a large proportion of the lines of force emanating from the magnet are guided by the stator and the rotor.Type: GrantFiled: February 21, 2011Date of Patent: March 26, 2013Assignee: Robert Bosch GmbHInventors: Ludwig Schoen, Florian Esenwein
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Patent number: 7960888Abstract: An electric motor comprising a rotor, a stator and a field weakening device. The rotor has a plurality of magnets mounted thereto, and the stator is located adjacent to the rotor and has a plurality of slots defined therein. The slots define raised teeth and are wound with electrical wiring to generate a magnetic field when the wiring is energized with current. The field weakening device is made from a highly magnetically permeable material and a comparatively lower magnetically permeable material. The field weakening device is disposed between the rotor and the stator and is selectively movable between a first position to align the highly magnetically permeable material between the teeth of the stator and the magnets of the rotor and a second position to align the comparatively lower magnetically permeable material between the teeth of the stator and the magnets of the rotor.Type: GrantFiled: February 12, 2007Date of Patent: June 14, 2011Assignee: The Timken CompanyInventors: Xiaolan Ai, Bradley Mularcik, Richard Knepper
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Publication number: 20100117477Abstract: It is an objective to provide a permanent magnet synchronous motor that is highly efficient with low vibration and low noise. A stator 30 includes a stator core 1 that includes magnetic pole teeth 2 each formed between adjacent slots 3, and stator windings 4 that are provided in the slots 3 of the stator core 1. A rotor 40 includes a rotor core 5, a plurality of magnet retaining holes 8, permanent magnets 7 inserted in the magnet retaining holes 8, and a plurality of slits 6 in the rotor core 5 on an outer circumferential side of the magnet retaining holes 8. Among the slits 6, slits 6 in a vicinity of a magnetic pole center of the rotor core 5 are oriented in a direction where a magnetic flux generated by a permanent magnet 7 converges outside the rotor core 5, whereas slits 6 in a vicinity of a pole border portion of the rotor core 5 are oriented in another direction that is different from the direction of the plurality of slits 6 in the vicinity of the magnetic pole center of the rotor core 5.Type: ApplicationFiled: February 21, 2007Publication date: May 13, 2010Applicant: Mitsubishi Electic CorporationInventors: Hayato Yoshino, Yoshio Takita, Koji Yabe, Takashi Ishigaki, Koji Masumoto
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Publication number: 20100119390Abstract: An object is to provide a permanent magnet motor that highly reduces torque fluctuation, thereby reducing noise and vibration. The permanent magnet motor may be formed as follows: a length D of a permanent magnet 8 in a longitudinal direction is the same as or longer than a width A between sides of the magnetic pole tooth 3 in the circumferential direction in an end portion of the magnetic pole tooth 3, and a distance C between tip portions of a pair of the first slits 13a and 13b within the same pole is smaller than the width A between the sides of the magnetic pole tooth 3 in the circumferential direction in the end portion of the magnetic pole tooth 3. The permanent magnet motor, thus formed, may be characterized in that cut surfaces 12 face the first slits 13a and 13b.Type: ApplicationFiled: February 26, 2007Publication date: May 13, 2010Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Kazuhiko Baba, Hayato Yoshino, Koji Yabe, Masahiro Nigo, Koji Masumoto, Tomoaki Oikawa, Yoshio Takita
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Patent number: 6984910Abstract: A coil retention system for a rotor of an electrical generator, such as an aircraft generator, that includes one or more components made of a high strength, lightweight composite material. By making one or more of the coil retention system components of a high strength, lightweight composite material, the generator can rotate at relatively high speeds, and can be built with a relatively small space between the generator rotor and stator. This allows the generator to supply greater output power without increasing the generator's size and/or weight.Type: GrantFiled: January 13, 2003Date of Patent: January 10, 2006Assignee: Honeywell International, Inc.Inventors: Edward M. Down, Kieran Doherty, David E. Stout
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Patent number: 6933818Abstract: A torque motor may include a rotor having at least two magnets disposed thereon, and a stator having a core and at least one coil. The magnets are arranged and constructed so that the outer surfaces thereof alternately have a N pole and a S pole. The magnets cover the rotor over an angle of less than 360 degrees. The core has a first and second magnetic pole elements. The magnetic pole elements are arranged and constructed such that an angle defined between a first straight line passing through a center of the first magnetic element and a center of rotation of the rotor and a second straight line passing through a center of the second magnetic element and the center of rotation of the rotor is less than 180 degrees.Type: GrantFiled: June 24, 2004Date of Patent: August 23, 2005Assignee: Aisan Kogyo Kabushiki KaishaInventor: Susumu Kaneshige
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Patent number: 6903469Abstract: A stepping motor includes a stator and a permanent-magnet rotor having a rotor axis. The stator is a stator blade made of soft magnetic materials whose center position is a rotor hole accommodating the rotor. Coils are provided on two sides of the stator blade. Within the stator blade are located three narrow grooves, each of which is disposed at an angle of 120° to one another along a radial direction of the rotor. Two ends of the narrow grooves are connected with the stator blade, and when a current is present in the coils a magnetic-pole end surface surrounding the rotor hole is formed by the part of the motor between two of the narrow grooves. The stator blade of the stepping motor is solid, resistant to twist and easily machined and assembled.Type: GrantFiled: November 20, 2003Date of Patent: June 7, 2005Assignee: Wellgain Optical Communications LimitedInventors: Tai Wo Ng, Roberto Zafferri
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Patent number: 6858956Abstract: A rotor (17, 31, 71, 91, 101, 121, 131, 141, 201, 401) of a motor (13, 51) is provided with a rotation shaft (21, 59, 410) and a plurality of magnets (15, 53, 75, 105, 210A, 210B, 411) on a circular periphery. Plates (25, 25A, 25B, 25C, 63, 77, 220, 300, 430) made of magnetic materials are provided so that each of which is magnetized by leakage flux of a corresponding magnet (15, 53, 75, 105, 210A, 210B, 401). The plates (25, 25A, 25B, 25C, 33, 63, 77, 107, 220, 300, 430) are disposed along a circular path such that a maximum flux density is formed at both peripheral ends. A magnetic sensor (27) outputs a signal in response to the variation of a flux density on the circular path.Type: GrantFiled: February 8, 2001Date of Patent: February 22, 2005Assignee: Nissan Motor Co., Ltd.Inventor: Yuki Nakajima
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Patent number: 6838799Abstract: A DC motor apparatus includes a motor housing assembly which includes an outer liquid-tight coolant chamber and an inner, armature-reception chamber portion. Pairs of permanent magnet stator magnet modules are housed within the liquid-tight coolant chamber, and shunt members are housed within the liquid-tight coolant chamber between the stator magnet modules. An armature is centrally located in the inner, armature-reception chamber portion. The armature includes at least one pair of armature pole portions which are wound with same-directional windings. A commutator is connected to the armature, and the commutator includes commutator contacts. An adjustable brush advance/retard mechanism includes roller brushes for contacting the commutator contacts. A liquid cooling system includes a coolant pump and a coolant fluid radiator for circulating liquid coolant through the liquid-tight coolant chamber for cooling the stator magnet modules and the shunt members.Type: GrantFiled: June 30, 2003Date of Patent: January 4, 2005Inventor: Joseph C. Caiozza
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Patent number: 6803691Abstract: An electrical machine comprises a magnetically permeable ring-shaped core centered on an axis of rotation and having two axially-opposite sides. Coils are wound toroidally about the core and disposed sequentially along the circumferential direction. Each coil includes two side legs extending radially alongside respectively sides of the core. Coil-free spaces exist between adjacent side legs. A bracket has first and second side flanges that are connected by a bridging structure and respectively abut the first and second sides of the coil.Type: GrantFiled: July 7, 2003Date of Patent: October 12, 2004Inventor: Mitchell Rose
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Patent number: 6777835Abstract: The apparatus for cooling a high power electrical transformer and electrical motors uses thermally conductive material interleaved between the turn layers of a high power transformer and iron core laminates to provide a low resistant thermal path to ambient. The strips direct excess heat from within the interior to protrusions outside of the windings (and core) where forced air or thermally conductive potting compound extracts the heat. This technique provides for a significant reduction of weight and volume along with a substantial increase in the power density while operating at a modest elevated temperature above ambient.Type: GrantFiled: July 30, 1999Date of Patent: August 17, 2004Assignee: The United States of America as represented by the Secretary of the NavyInventor: Eddie Sines
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Patent number: 6777848Abstract: a high-voltage generator, notches (3) leading radially inward are provided in each segmental lamination (1) on the radial outside of the laminated stator body and end in a relief opening. The notches (3) cause the amplitude and the frequency of, for example, a 4-node vibration occuring during operation to be limited to noncritical values, although the laminated body is undersized mechanically with regard to its yoke height (JH).Type: GrantFiled: December 23, 1998Date of Patent: August 17, 2004Assignee: AlstomInventors: Reinhard Joho, Albrecht Bock
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Publication number: 20030230950Abstract: An electric motor is provided with rotor and stator. The stator includes stator poles radially facing the rotor and surrounded by stator windings. An insulating sleeve is positioned between the rotor and stator. The sleeve includes projections arranged radially with respect to the rotor. The projections project in a direction away from the sleeve and rotor and towards the stator. The projections project between adjacent stator poles and may further serve to anchor the poles. The projections may have a T or elongated T shape. The projections and sleeve are rigid and either or both may be made of plastic. The sleeve provides a moisture or liquid tight insulation for the stator so that the motor can be used in moist or liquid environments.Type: ApplicationFiled: June 13, 2003Publication date: December 18, 2003Inventor: Christian Reimann
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Patent number: 6566784Abstract: The present invention provides a stator structure, which keeps a lower cogging torque in the rotation direction of a motor at the same time of raising the magnetic reluctance between adjacent tooth holders of the stator. A tooth-holding end of each of each of the tooth holders in the rotation direction of heavy load is reserved, while the other tooth-holding end in the reverse direction is cut, hence forming a single-arm tooth holder with two asymmetric sides. Because a higher magnetic reluctance is generated between adjacent single-arm tooth holders, the self coupling phenomenon of magnetic lines of force between adjacent tooth holders of the stator can be reduced when the magneto motor operates under a high load. Armature reaction of the magneto motor operating under a high load can thus be intensified to enhance the operational efficiency, stability, and smoothness thereof.Type: GrantFiled: May 16, 2002Date of Patent: May 20, 2003Inventor: Chun-Pu Hsu
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Publication number: 20030067237Abstract: A permanent magnetic type electric rotating machine includes: a stator having armature winding arranged in several slots formed in a stator core; and a rotor having permanent magnets held in several permanent magnetic insertion holes formed in a rotor core, in which a peripheral surface of the rotor core is configured to be a combination of arcs around two points different from a center of the rotor core for each magnetic pole in such a manner that when an axis extending in a central direction of a magnetic pole of the rotor is a d axis, and an axis extending in a direction between magnetic poles that is offset from the central direction of the magnetic pole by 90 electrical degrees is a q axis, a radial distance from a center of the rotor core to a periphery of the rotor is reduced gradually from the d axis to the q axis.Type: ApplicationFiled: March 20, 2002Publication date: April 10, 2003Inventors: Ryoichi Takahata, Shinichi Wakui, Haruo Koharagi, Satoshi Kikuchi, Miyoshi Takahashi
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Publication number: 20020093265Abstract: The invention relates to a continuous rotation or a multi-position actuator. The continuous rotation armature has at least two poles spaced apart from the armature and a third pole that is adjustable in distance from the armature. The multi-position actuator comprises a housing, an armature rotatably mounted in the housing, and a series of poles journaled around the armature. There is also a stop arm attached to the armature, which stops the rotation of the armature when the stop arm hits an adjacent stop. These stops are positioned within the housing to limit the rotation of the armature. This multi-position actuator is designed to form either a fail safe actuator or a latching actuator by adjusting the spacing of the air gap between the poles and the armature. The fail safe actuator is designed so that the stop arm attached to the armature is positioned between the stops when the poles are not charged.Type: ApplicationFiled: January 12, 2001Publication date: July 18, 2002Inventor: Victor Nelson
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Patent number: 6249070Abstract: A shaft (14) is formed with a magnetically transparent portion within its length, so as to enable passage therethrough of electromagnetic flux from stator poles, to a further shaft (20) to cause shaft (20) to move to a position in space, coaxial with the shaft (20).Type: GrantFiled: October 14, 1999Date of Patent: June 19, 2001Assignee: Rolls-Royce PLCInventor: John Sharp
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Patent number: 6236135Abstract: To provide a toroidal core type actuator having a stator unit which is increased in winding density, is improved in methods of the terminal handling after winding, the positioning of the stator after winding, and the fixing of the same, and is excellent in working properties. A toroidal core type actuator having a stator and a rotor is provided, the stator having winding applied to a hollow cylindrical core composed of soft magnetic material, the rotor including a permanent magnet having north poles and south poles alternately arranged in total of m along the circumferential direction thereof, the rotor being rotatably arranged in the core of the stator via a minute air gap, wherein m of phase separators composed of non-magnetic material are arranged on the peripheral surface of the hollow cylindrical core so as to be separated from each other by 360°/m and the winding is applied to winding regions separated from each other by the phase separators.Type: GrantFiled: December 9, 1999Date of Patent: May 22, 2001Assignee: Minebea Co., Ltd.Inventors: Yuzuru Suzuki, Sakae Fujitani, Takashi Ishii, Naoyuki Harada
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Patent number: 6166463Abstract: The present invention resides in a radial air gap machine with a serrated air gap that can minimize external axial forces. This is accomplished by controlling the relationship between the air gap surfaces in the stator and rotor sections. To control the relationship between the stator sections and the rotor section in a vertical motor a bushing with external and internal thread of opposite hand with the internal thread having a steeper helix angle is twisted into a bearing mount and over a motor shaft. Thus, a vertical hollow shaft motor with magnetic balance thrust is adjusted.In axial air gap machines, the magnetic force produced in the air gaps can also be utilized to compensate for axial loads.Type: GrantFiled: November 25, 1998Date of Patent: December 26, 2000Inventor: Richard C. Woodward, Jr.
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Patent number: 6034462Abstract: A cylindrical or radial air gap, electrical machine is defined which comprises a circular rotor section having a serrated circular surface area mounted on a shaft with rotation means, two or more circular stator sub sections having circular serrated surface areas are assembled around the circular rotor section, which define an air gap between them. Normally after stator sub sections are assembled around the circular rotor section, end brackets or housings units are usually clamped around them.Type: GrantFiled: November 20, 1998Date of Patent: March 7, 2000Inventor: Richard C. Woodward, Jr.
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Patent number: 6031311Abstract: A brushless DC motor has a stator and a rotor. The stator has a stator core and excitation coils wound around the stator core. The rotor has a rotor core disposed at the inner space of the stator, and many permanent magnets inserted into the rotor core. The permanent magnets are symmetrically tilted with respect to a radial direction of the rotor core. The rotor core is formed with slots for cutting off a magnetic field between the permanent magnets adjacent to each other. The slots are parallel with an axis of the rotor core. The slots are formed between ends of the permanent magnets adjacent to each other at an outer part of the rotor core. The vortex of magnetic flux between the permanent magnets is prevented by the slots.Type: GrantFiled: November 10, 1998Date of Patent: February 29, 2000Assignee: Samsung Electronics Co., Ltd.Inventor: Sang Cheol Lee
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Patent number: 5880546Abstract: A magnetic actuator, for example a magnetic bearing, embodies a fixed part and a mobile part. These parts are ferromagnetic and form an airgap between them extending parallel to a predetermined first direction. The magnetic actuator further embodies a nonmagnetic wall interposed in the airgap. The wall is that of a confinement chamber, for example. In this magnetic actuator one of the fixed and mobile parts embodies fingers penetrating the nonmagnetic wall and directed towards the other of the fixed and mobile parts.Type: GrantFiled: March 12, 1997Date of Patent: March 9, 1999Assignee: Aerospatiale Societe Nationale IndustrielleInventors: Olivier Marroux, Patrice Jamain, Charles Lambert
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Patent number: 5420471Abstract: An electric generator which can be powered using a minimal amount of mechanical power, and in particular, an electric generator having a weak electromagnet which acts as a stator core, thus enabling electric power generation to occur while only minimal amounts of mechanical power are utilized. The generator comprises two annular ferromagnetic silicon steel plates inserted between non-magnetic plates to thus define a stator core with a stacked silicon steel plate and non-magnetic plate arrangement. The internal diameter of the ferromagnetic silicon steel plates is preferably at least 5 millimeters larger than that of the non-magnetic plates. Consequently, a strong magnetic field cannot be formed around the stator core, and as a result, the generator's rotor can be rotated using minimal amounts of mechanical power.Type: GrantFiled: October 13, 1993Date of Patent: May 30, 1995Inventor: Ja D. Yun
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Patent number: 5369323Abstract: A stepper motor is provided that is compact, easily manufactured, and provides high torque. The stepper motor comprises a multi-pole composite magnet which functions as a rotor, at least one stator member which determines the angular position of this rotor, and means for positioning the rotor and the stator members on a common axis. The composite magnet comprises two pieces, each piece having a mating member and an arc-shaped member integrally formed with the mating member. To form the composite magnet, the mating members of both pieces are aligned on an axis and the arc-shaped members of both pieces are juxtaposed. The first and second pieces are magnetized in opposite axial directions which results in two advantages. First, the composite magnet provides a high area of energy conversion per unit volume, thereby significantly reducing the size of the stepper motor in comparison to prior art stepper motors.Type: GrantFiled: June 7, 1993Date of Patent: November 29, 1994Assignee: Slonix EngineeringInventor: Elmer C. Allwine, Jr.
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Patent number: 5306977Abstract: A rotor for an alternator mounted on a vehicle comprises first and second claw-pole members formed of magnetic material and mounted on a shaft rotatable about an axis. The first and second claw-pole members have at least one first axially extending claw section and at least one second axially extending claw section respectively. The at least one first and second axially extending claw sections have a first side face and a second side face respectively. A field coil is disposed between the first and second claw-pole members. A permanent magnet is disposed between the first and said second side faces and is polarized in a direction which prevents magnetic flux leakage between the at least one first and second axially extending claw sections. The rotor has a space formed between the permanent magnet and at least one of the first and second side faces.Type: GrantFiled: August 7, 1992Date of Patent: April 26, 1994Assignee: Nippondenso Co., Ltd.Inventor: Seiji Hayashi
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Patent number: 5175460Abstract: A DC motor including a rotatable armature, a pair of permanent magnets functioning as magnetic stator poles, and a flat yoke having a pair of opposed arcuate sections and a pair of opposed flat sections, for receiving the armature. Each of the arcuate sections is formed with a slit extending parallel to the rotational axis of the armature to increase the magnetic reluctance. The magnetic reluctance against a magnetic flux generated by the cross magnetomotive force is increased to reduce the armature reaction by the slits.Type: GrantFiled: January 22, 1992Date of Patent: December 29, 1992Assignee: Asmo Co., Ltd.Inventor: Toshiyasu Ishizuka
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Patent number: 5122704Abstract: Leakage of a coolant into the air gap (16) of a dynamoelectric machine so as to cause undesirable windage losses may be avoided through the use of a composite rotor sleeve (44) including a continuous film (46) of polyimide material on its radially inner surface and surrounding the machine rotor (22).Type: GrantFiled: October 25, 1990Date of Patent: June 16, 1992Assignee: Sundstrand CorporationInventors: Anthony Blakeley, Clarence F. Dolan, Walter Iseman
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Patent number: 5070264Abstract: DC motors without collectors require position sensors, which recognize or identify the angular position of the rotor, in order to supply a pulse for control of the current in the coil at a suitable point in time. Hall probes which, as a rule, are used as positional sensors, involve a series of disadvantages, such as for instance sensitivity to temperature and radiation. In order to avoid these disadvantages, coils with a magnetic core through which alternating current is passed are installed in the stator-rotor air gap in accordance with the invention. The rotor comprises in the axial segment opposite the coils a magnetic portion and a nonmagnetic portion. This generates a change in the voltage drop at the coil during each rotor revolution.Type: GrantFiled: September 14, 1990Date of Patent: December 3, 1991Assignee: Arthur Pfeiffer Vakuumtechnik Wetzlar GmbHInventor: Armin Conrad
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Patent number: 4990809Abstract: A high torque-to-low mass variable reluctance motor includes a cylindrical stator assembly having a plurality of stator segments circumaxially arranged about a rotor wherein adjacent stator segments are maintained in a spaced apart relation with one another by non-magnetic pins which provide a radially inwardly projecting channel extending fully from the outer circumference to the inner circumference of the stator assembly to essentially magnetically isolate the stator segments from one another. A generally annular, non-magnetic shell coaxially surrounds and engages the outer periphery of the circular stator assembly to cause a compressive force to be directed radially inwardly to maintain the stator segments in a precisely aligned arrangement.Type: GrantFiled: April 27, 1987Date of Patent: February 5, 1991Assignee: The Superior Electric CompanyInventors: Richard J. Artus, Anthony E. Balestro, Allen R. Perrins, Peter Senak, Jr.
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Patent number: 4990806Abstract: In a pulse motor comprising a rotor, a drive coil excited by a predetermined drive current to drive the rotor, and a yoke for guiding a magnetic flux generated by the drive coil to a predetermined magnetic path; the yoke is provided with an aperture to restrict the flow path of an eddy current induced by the magnetic flux generated by the drive coil.Type: GrantFiled: April 27, 1989Date of Patent: February 5, 1991Assignee: Oki Electric Industry Co., Ltd.Inventors: Hiroshi Kikuchi, Jiro Tanuma, Tadashi Kasai, Masayuki Ishikawa
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Patent number: 4843271Abstract: A rotor of a dynamoelectric machine includes a coating of a high-conductivity metal covering a substantial portion of the surface thereof. The high-conductivity metal reduces resistive heating produced by eddy currents from high-frequency harmonics of an AC power source. In one embodiment of the invention, surfaces of dovetail wedges retaining energizing conductors in logitudinal slots are coated with a copper coating. The pole regions of the rotor include undercut slots to retain chamfered wedges of magnetic material coated with a high-conductivity metal. Retaining rings at opposed ends of the rotor may also be coated with a high-conductivity metal.Type: GrantFiled: December 10, 1987Date of Patent: June 27, 1989Assignee: General Electric CompanyInventor: Manoj R. Shah
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Patent number: 4623811Abstract: Structure for maintaining accurate spacing between opposed pole elements of a split-field coil structure. The motor structure includes a support for supporting the armature for rotation about an axis and a field coil structure having opposed C-shaped laminated cores. Each core has a pair of legs forming motor poles, each pole being defined by an arcuate surface spaced radially from the armature and a distal end surface. The core further defines a bight portion extending between the legs. The field coil is wound about a two-piece bobbin which serves further to retain the laminations of the field coil in stacked, assembled relationship. The end surfaces of the legs of the cores are in spaced, opposed alignment, with the support portion fitting therebetween for providing the accurately maintained minimum spacing between the pole end surfaces.Type: GrantFiled: May 22, 1985Date of Patent: November 18, 1986Assignee: Whirlpool CorporationInventors: Arne M. Nystuen, John M. Kuss
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Patent number: 4510407Abstract: A permanent magnet type motor having a stator which comprises a yoke, a plurality of main magnetic poles made of permanent magnets, and a plurality of auxiliary magnetic poles, each of the main magnetic poles and each of the auxiliary magnetic poles being juxtaposed on the inner peripheral surface of the yoke, wherein each of the auxiliary magnetic poles has an axial length larger than the thickness of an armature core and smaller than the axial length of each of the main magnetic poles, wherein each of the main magnetic poles has an inner diameter smaller than the inner diameter of each of the auxiliary magnetic poles, wherein each of the main poles, before being secured on the yoke, is machined to have the inner diameter smaller than the predetermined inner diameter by a thickness to be machined, and wherein each of the main magnetic poles is machined to have the predetermined inner diameter after it has been secured together with each of the auxiliary magnetic poles onto the yoke.Type: GrantFiled: June 9, 1983Date of Patent: April 9, 1985Assignee: Hitachi, Ltd.Inventor: Tosio Tomite
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Patent number: 4454439Abstract: In large capacity and superconducting rotating electric machines, the stator coil windings are frequently placed in the air gap between the stator core and the rotor. This so-called air gap winding rotating electric machine has the drawback that reliably securing the stator coils to the stator core is difficult. In the air gap winding rotating electric machine according to the present invention, the stator coils are disposed between the outer circumference of a thin-walled electrically insulating cylinder surrounding the rotor and the inner circumference of the magnetic shield on the stator side. Taper keys are inserted between the outer circumference of the stator coils and the inner circumference of the magnetic shield so as to firmly press the stator coils against the thin-walled electrically insulating cylinder. In this manner, the stator coils can be easily and reliably secured to the stator.Type: GrantFiled: February 28, 1983Date of Patent: June 12, 1984Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Kouichi Okamoto, Mitsuhiro Uchida, Tatsuei Nomura
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Patent number: 4132932Abstract: A motor is disclosed in which the main stator winding of, for example, a squirrel case inducting motor, is connected in series with a capacitor so that the capacitor, together with the input voltage, causes the stator core to periodically switch from a nonsaturated to a saturated condition and vice-versa so that the flux density is maintained at a uniform high level. A second stator winding is provided in parallel with the first stator winding and capacitor which second winding serves as the phase winding and causes the motor to operate as a balanced split phase motor having a high efficiency over a broad range of operating points.Type: GrantFiled: December 12, 1977Date of Patent: January 2, 1979Inventor: Cravens L. Wanlass