Abstract: A disc driving motor for rotating a recording medium in the form of a disc of the type having a disc-shaped rotor yoke around the outer peripheral portion of which is securely joined a driving magnet for generating a rotating force, an auxiliary yoke attached around the outer periphery of the rotor yoke so as to avoid magnetic saturation of the rotor yoke and leakage of the magnetic fluxes from the driving magnet through the outer peripheral portion of the rotor yoke to the exterior. The tops of screws for securely maintaining the core yoke at a predetermined position are not extended beyond the surface of the core yoke in opposing relationship with the rotor yoke.

Abstract: A stator for a fractional horsepower motor has a mounting hole of reduced dimensions for fixing the position of motor mounting brackets which support a rotor. The configuration of the mounting holes increase the area where magnetic flux may pass. One configuration reduces the depth of the mounting hole to one or two laminates of each side of the stator. Another configuration is an elongated hole which lies in the direction of the magnetic flux. Each laminate may have a tang which interlocks with tangs on other laminates when the laminated stack is squeezed together in a punch press.

Abstract: The invention is directed to an electric motor construction having a magnetic flux return path which exhibits very low losses due to eddy currents or hysteresis, and simplifies construction thereof. In the motor construction, the magnetic flux return path is constructed from discrete magnetic material wire which is wrapped or otherwise formed in the desired return path configuration. The magnetic material wire is wound in a direction which generally crosses the flow of magnetic flux and yet is substantially tolerant of cross-winding fields. In this way, the flux return path provides easy construction in that coil winding techniques may be used, and the winding direction is less critical as it can cross the flow of flux therein. The flux return path greatly reduces eddy current losses as the cross section of the path to eddy current flow is the cross section of discrete wires, and because the discrete wires are formed with high packing fraction which will minimize skin effects especially at high frequencies.

Abstract: An electromotive device is disclosed which utilizes stacks of oriented magnetic material as stator bars. Electrical conductors are wound about the stator bars to create a stator inductor. The stator bars are generally configured to shield the electrical conductor winding from electromagnetic forces and further, to provide a first flux return path for the magnetic flux created by magnets fixed to a rotor for movement with respect to the stator inductor.

Abstract: A primary for a linear induction motor is formed from laminae which are bolted together. The bolts are located in protuberances on the opposite edge to the teeth so as to be outside the path of substantial flux penetration.

Abstract: 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.

Abstract: Traditional alternators, that is those non-inductor alternators employed in machines such as automobiles, provide either moving conductors which cut through a stationary magnetic field, or a moving magnetic field which passes over stationary conductors. In conventional inductor alternators, neither the field nor armature rotate. An electromotive force is induced in the output windings by periodic changes in the local reluctance of the magnetic circuit carrying the magnetic flux. The reluctance is governed by the shape of the rotor relative to the stator. By the elimination of the stator housing and of the rotor encompassing stator, this invention provides for the use, as inductor alternator rotors, of components which previously could not function as rotors.

Abstract: This invention concerns an electromagnetic motor. Such motor includes: a rotor (1) comprises a bipolar permanent magnet, a stator (2) provided with a peripheral stator portion (14) forming a low reluctance magnetic circuit (CM) and an interior or central stator portion (12) on which are arranged n branches including first ends forming polar expansions and second or free ends, and windings (22, 24, 26) adapted to generate a magnetic flux, such motor being characterized in that the windings (22, 24, 26) are mounted on and are respectively anchored at least to the second or free ends of the branches. Such motor is applied for example to operation in a three-phase energization mode.

Abstract: Disclosed is a rotary actuator having a rotor and a stator which rotatably supports the rotor. The stator includes a coil bobbin, a stator coil, a pair of tapered poles and a yoke. The coil bobbin is formed from a non-magnetic material into a cylindrical shape and has the stator coil wound circumferentially thereabout. The pair of poles are disposed on the internal circumference of the coil bobbin. The yoke covers the outer surface of the coil bobbin and is in contact with the respective poles. The rotor comprises a rotary shaft and a diametrically polarized cylindrical magnet. The rotary shaft is inserted into the coil bobbin and is rotatably supported by the yoke. The magnet is carried by the circumference of the rotary shaft and is rotatable integrally therewith.

Abstract: A dc electric motor having a rotor, a stator, and at least a pair of oppositely disposed main magnets associated with one of the rotor and stator is provided. Preferably, the main magnets are associated with the stator in a stator assembly. The stator assembly also includes interpolar diverting magnets positioned on each side of each main magnet. Additionally, an end diverting magnet assembly including at least a pair of oppositely disposed end diverting magnets may be positioned at at least one end of the stator assembly. Each of the interpolar diverting magnets and end diverting magnets have a magnetic field perpendicular to the magnetic field of the main magnets and are oriented to increase the flux density of the main magnets with low magnetic leakage.

Abstract: A small stepping motor has a rotor comprised of a rotatably mounted and radially magnetized permanent magnet having a plurality of magnetic poles, a stator having a plurality of magnetic pole portions positioned to face the rotor, a coil wound around the stator, and a driving circuit for controlling the exciting current supplied to the coil. A leakage flux converging member is positioned in the vicinity of the stator so that leakage magnetic flux from the stator or the coil is converged by the leakage flux converging member so as to pass through the stator.

Abstract: An electromagnetic clutch includes a clutch rotor having a first friction surface and an annular armature plate having a second friction surface. The first friction surface and the second friction surface face each other. A friction member made of nonmagnetic material is fixedly disposed within a second groove formed at the second friction surface of the annular armature plate. A first end surface of the friction member projects with respect to the second friction surface of the annular armature plate. The first friction surface of the clutch rotor is provided with a first annular groove to receive the projecting portion of the friction member. Therefore, the depth of the second groove becomes smaller. Consequently, the number of magnetic lines of flux which radially penetrate through an annular portion of the annular armature plate at the location of the second groove is enhanced.

Abstract: A magnetic bearing has a number of pole pieces disposed about the circumference of the shaft supported by the bearing. To inhibit magnetic flux migration within the bearing, magnetic barriers of non-magnetic material are interposed between pole pieces at selected locations. Magnetic guides prevent magnetic saturation of the bridging portion of the pole pieces prior to the poles' saturating.

Abstract: The synchronous motor has a pick-up (C) measuring the position of its rotor and a power-varying circuit (VP) operating as a current generator. A power-varying circuit (VP) is controlled by a programmed microprocessor (MP) receiving information specifying the desired speed for the motor (M), information representative of the difference between the current speed and the desired speed for the motor, information from said pick-up relating to the position of the rotor of the motor, and stored information in order to enable it to force zero phase difference between the current I delivered by the power-varying circuit and the potential difference U across the terminals of the motor windings, thereby minimizing the installed power required of the power-varying circuit in order to run the synchronous motor and power-varying circuit at constant power. A control system operates the motor at constant power.

Abstract: An electromagnetic switch device for a starter motor has a plunger 21 defining a cylindrical body 22 slidably fitted in a sleeve 8, and a trumpet shaped intermediate plate 23 which generally extends in a plane perpendicular to the central axis of the cylindrical body. At least part of the cylindrical body has a thin-walled portion which extends in a direction opposite the extension direction of a cylindrical rod 24 driven by the plunger, from a junction 21a to the radially outer portion of the intermediate plate.

Abstract: A dc electric motor having a rotor and a stator and at least a pair of oppositely disposed main magnets associated with one of the rotor and stator and including an end diverting magnet positioned at each end of each main magnet. The diverting magnets have a magnetic field perpendicular to the magnetic field of the main magnets and are oriented to increase the flux density of the main magnets with low magnetic leakage. Preferably, the main and diverting magnets are arcuate shaped segments of approximately 120.degree.. In addition, an interpolar diverting magnet may be positioned on both sides of each main magnet.

Abstract: An electromagnetic clutch is disclosed which includes a rotor having a friction surface and an armature plate having a friction surface. Both friction surfaces face each other. An annular friction member of non-magnetic material is fixedly disposed on the friction surface of the armature plate. The thickness of the annular friction member is gradually decreased from its radially-outer edge to its radially innermost edge, thereby preventing the restriction of the number of magnetic lines of flux which radially penetrate through the armature plate. The decreasing thickness increases the magnetic attraction between the armature plate and the rotor without increasing the weight of the electromagnetic clutch.

Abstract: In an angular pulse generator having a movable generator part and a read head, the read head has a primary winding (W1) fed with an alternating voltage of a defined frequency and has a secondary winding (W2) whose induced secondary voltage is modulated by passing teeth and intervening gaps of the generator part. An evaluation unit evaluates the phase difference between the alternating voltage and the secondary voltage and forms a pulse for every passing tooth. A stray flux return line surrounds the primary winding (W1), so that the majority part of the primary flux linked to the primary winding (W1) flows via the stray flux return line for a large gap distance of the generator part.

Abstract: An electromagnetic device such as an electromagnetic brake or an electromagnetic coupling comprises an electromagnet, at least two parts arranged so that, when the electromagnet is switched on, a magnetic flux extends through the parts. Formations reducing residual magnetism in the parts, including a plurality of gaps formed as slots, are provided in at least one of the parts, such that this part remains a one-piece member.

Abstract: A drive unit for direct drive of an information-storage disk comprises a brushless dc external-rotor motor having a permanent-magnet rotor magnet arrangement of considerably reduced axial length. Electrostatic charge is removed from the rotor shaft by a metallic spring element which engages the shaft periphery from within the interior of the rotor housing. An electromagnetic braking arrangement is located interiorly of the housing. The packet of stator plates for the stator has an axial length shorter than that of the rotor magnet arrangement, but is provided at its axial end faces with skirted-rim flux-conducting elements whose peripheral skirt portions form useful-air-gap extensions in cooperation with the rotor magnet arrangement.

Abstract: A lightweight electromotive device with a high power-to-weight ratio capable of operating as an efficient motor, alternator or generator includes an mangetic-flux producing assembly comprising spaced magnetic elements, and an armature assembly formed by winding conductive, non-magnetic wire, such as copper wire on flux carrying core or stator bar elements. The elements are shaped to form an eddy current shield for the windings and provide two heat radiating surfaces. This allows the device to operate with minimal eddy current losses and maximum radiation and convection cooling. The armature windings and flux carrying elements are dispersed as a further measure to avoid creating opposing induced currents.

Abstract: In a dynamoelectric machine which includes a rotor and a stator, an integral magnetic isolation and cooling system. A housing is disposed about the machine, the housing being fabricated of magnetically permeable material to define a flux path therethrough. A cooling jacket is sandwiched between the housing and the stator. The cooling jacket has coolant passages therein and is fabricated of non-magnetic material to isolate the flux path between the housing and the stator.

Abstract: A brushless DC motor in which a rotary axis is rotatably mounted in a bearing portion of a stator housing, a rotor yoke is fixedly mounted on an end portion of said rotary axis, a magnet member is mounted on the face of said rotor yoke, a return yoke of ring shape is mounted to one face of said stator housing, a plurality of circumferentially extending cavity portions are formed in said return yoke spaced apart from each other in the radial direction relative to the rotary axis, and a driving coil is positioned facing said rotor yoke.Therefore, core loss caused in said return yoke is reduced by said cavity portions of said return yoke, whereby it is able to obtain high stability at high speed rotation.

Abstract: A hybrid stepper motor having two alternately excited magnetic systems, one providing positions of 0.degree. and 180.degree., and the other positions of 90.degree. and 270.degree.. To minimize position offset due to unequal flux through the two air gaps of the unexcited system, a nonmagnetic space is provided to reduce the relative difference in reluctance between the magnetic paths which include the two air gaps of the unexcited magnetic system.

Abstract: A motor with DC brake having a DC electromagnetic brake (10) arranged on the shaft (14) of the rotor (16) thereof, in which a partial shaft (14b) extending through and outward from the DC electromagnetic brake (10) is formed of a nonmagnetic metal material. A partial shaft (14a) extending through the rotor (16) is formed of a free cutting metal material, and partial shafts (14a) and (14b) are coaxially united to form the integral shaft (14) at a junction (18) by friction welding.

Abstract: A plurality of motors are arranged on opposite surfaces of a single magnetic base plate such that they are magnetically isolated from each other by the base plate. Such an arrangement prevents the motors from magnetically interfering with each other and, thereby, allows them to be positioned as close to each other as possible, in order to cut down the overall size of an apparatus in which the motors are installed.

Abstract: A high speed induction motor comprising a stator and a rotor coaxially positioned within the stator, and mounted in a suitable frame having a water cooled jacket. The stator includes a multiphase winding 16 on a laminated core 18, and having stainless steel end plates 24. Cooling coils 30 are around the end turn portions of the windings, and layers of insulation 28 are between the windings and the cooling coils. The rotor 12 has a core section 37 and an integral shaft 38. A plurality of elongated conductor bars 40 fit tightly into semiclosed elongated slots 42 in the rotor core 37, the slots and bars preferably having a wedge shaped cross section, and having a narrow neck portion adjacent the outer periphery of the rotor core, forming rotor teeth 54 between adjacent conductor bars. Copper end rings 68 are provided at opposite ends of the rotor core, with reduced opposite end portions 76 of the conductor bars received and brazed within spaced slots 70 around the periphery of the end rings.

Abstract: A drum type homopolar dynamoelectric machine includes a rotor, a main field coil and an auxiliary field coil. The field coils encircle different portions of the rotor and are supported by a stator structure having a main pole piece for directing magnetic flux produced by current flowing in the main field coil radially into a section of the rotor. A current transfer assembly makes sliding electrical contact with a current collecting zone on the surface of the rotor which is axially positioned between the main and auxiliary field coils. Current flowing in the auxiliary field coil tends to reduce the amount of leakage flux in the current collecting zone produced by current flowing in the main field coil. This reduces undesirable circulating currents in the rotor current collecting zone and the associated current collecting structures.

Abstract: A drum-type homopolar dynamoelectric machine includes a rotor and an annular field coil encircling a portion of the rotor. The field coil is supported by a stator structure having a main pole piece for directing magnetic flux produced by current flowing in the coil, radially into a section of the rotor. A current transfer assembly makes sliding electrical contact with a current collecting zone on the surface of the rotor and is axially positioned between the main pole piece and an end pole piece of the stator which directs magnetic flux axially out of the end of the rotor. A magnetic flux shield is positioned adjacent to the field coil to minimize leakage flux, caused by current flowing in the field coil, in the vicinity of the current collecting zone of the rotor. This reduces undesirable circulating currents in the rotor current collecting zone and the associated current collecting brushes.

Abstract: A rotor for use with a hysteresis motor in combination with a centrifuge rotor having a hub. The motor has a stator with an axial length and the motor rotor has a region coextensive with the stator. The motor rotor includes a hollow cylindrical body made of a magnetizable material, having one end firmly connected to the hub, and having a wall with a first thickness in the region that is coextensive with the stator and a second thickness, smaller than the first thickness, which is outside of the region that is coextensive with the stator and which is in the region of the connection of the cylindrical body with the hub. The point of transition from the first thickness to the second thickness of the wall is a predetermined distance from the nearest point of contact of the hub with the cylindrical body so as to increase the magnetic resistance between the hub and the cylindrical body.

Abstract: A permanent magnet type step motor comprising a rotor wherein a disc-like permanent magnet having a magnetic pole in an axial direction and a pair of rotor yokes holding the permanent magnet therebetween are integrally and coaxially mounted on a rotational shaft, and a stator having a stator core opposed to an outer circumference of the rotor yokes. The front and rear brackets are formed of a non-magnetic material in which a thin shield sheet of magnetic material is inserted therein, and the magnetic resistance between the rotor yokes and the ends of the brackets opposed thereto is increased to reduce the leaky magnetic flux from the motor.

Abstract: An end bracket for a motor comprising an inner wall and an outer wall. The inner wall is formed from a thin magnetic shielding material and the outer wall is formed from a non-magnetic material. The inner wall comprises: a larger-diameter cylindrical part having an outside diameter substantially equal to that of the stator core of a motor and further having an inner end in contact with said stator core; a smaller-diameter cylindrical part coaxial with the larger-diameter cylindrical part and having an outside diameter substantially equal to that of the rotor of the motor and further having an inner end facing said rotor across a gap; and an end disk part integrally connected to the outer ends of these cylindrical parts respectively.

Abstract: A means for preventing harmful interlaminar electrical currents from flowing within the stator core of dynamoelectric machines is disclosed. By providing an insulation between the building bolts and the step iron portion of the stator core, current flow is inhibited in the event that a portion of the stator core is electrically shorted between adjacent laminations. Electrical communication between the building bolt and the stator core laminations is prevented by an insulated cylinder disposed about the building bolt and cooperatively associated with two layers of plates which are disposed on the two axial extremes of a preselected segment of the stator core laminations.

Abstract: A circular-plate permanent magnet, with its one side being magnetized as N-pole while the other as S-pole, which is sandwiched between two rotor yokes made of a magnetic circular plate, is mounted on a rotor shaft as one unit, and this unit makes up the rotor. The stator, which is arranged in a position where its inner surface opposes the outer periphery of the aforesaid rotor across a small air gap, is firmly held between a front cover and a rear cover. Around the outer periphery of the aforesaid rotor yokes, toothed-wheel-like jags which provide the permeance variations are installed. By letting DC current flow stepwise through the stator coils which are wound around the aforesaid stator, the rotor rotates stepwise. With D.sub.1 and D.sub.2 being the outside diameter and the inside diameter respectively of the cylindrical part on the inside diameter side of the front cover and rear cover, D.sub.

Abstract: A magnetic shielding plate for decreasing the affects of external magnetic flux fields on a step motor in an electronic wristwatch is provided. Specifically, the step motor includes a permanent magnet rotor and a magnetic permeable stator surrounding said rotor for incrementally rotating said rotor in response to changes in the magnetic orientation of said stator. A coil assembly includes an elongated coil core coupled to the stator and a coil wrapped around the elongated core for receiving timekeeping signals. A magnetic shield plate extends the lengthwise extent of the elongated core for shielding the coil core from external magnetic fields surrounding the wristwatch. The minimum cross-sectional area of the shield in the direction perpendicular to the elongated core, taken along the lengthwise extent of the core, defines the magnetic shielding characteristics of the shielding plate.

Abstract: A method of making a leakage flux conducting device and securing it to a non-ferrous end plate of a prime mover. In this method, the device is formed with a mass great enough so that it remains unsaturated with respect to the leakage flux carried thereby, and the device is provided with a plurality of means arranged for deformation into engagement with associated parts of the end plate. The device is moved into an assembly position on the end plate, and the deformation means are deformed into engagement with the associated parts of the end plate thereby to prevent displacement of the device from its assembly position on the end plate.

Abstract: Laminated flux screens disposed between finger plates and end plates of a generator to reduce the axial flux striking the end region of the generator core.

Abstract: In a generator a plurality of laminations are disposed adjacent the stator teeth to extend radially outwardly from the rotor and generally perpendicular to the stator laminations to form a flux shunt to prevent fringing flux from entering the core perpendicular to the stator laminations.

Abstract: Armature reaction in a dynamo is reduced by constructing the main pole structure and/or the commutating pole structure with a plurality of iron lamina arranged parallel to the axis of rotation of the dynamo. The iron lamina are separated from each other by nonmagnetic or magnetically weak material of a predetermined thickness designed to cause a predetermined minimum but high reluctance to be offered to flux generated in the main or commutating pole structure as a result of armature current. The core of each pole may be split into a first and second core half at the root and in the direction of the axis of rotation. Each core half has a larger portion which extends to the adjacent core half of the neighboring pole, thereby forming a yoke. A smaller portion of each core half extends into the air gap between poles and, together with the corresponding portion of the core half of the neighboring pole which is similarly extended into the same air gap, forms a commutating pole.

Abstract: A prime mover has a non-ferrous end plate with a leakage flux conducting device disposed in a preselected assembly position thereon. The device conducts across the end plate leakage flux emanating from a magnetic field established between a pair of opposite pole winding means of the prime mover upon the energization thereof. Fingers integral with the device are provided for securing it in the preselected assembly position thereof on the end plate.

Abstract: A flux sensor is provided for measuring magnetic flux in laminated cores, and especially for measuring the axial flux in the end regions of the stator cores of large generators. The sensor comprises a flat, multi-turn coil of fine wire enclosed in an insulating enclosure which includes a pressure-supporting member of greater thickness than the coil. The sensor is thin enough to be placed between the laminations of a generator core and the high clamping pressure is carried by the pressure-supporting member which protects the coil. The leads are flat conductors brought out between the laminations to the periphery of the core. Such a sensor can remain permanently embedded in the core since it does not effect the core structure.

Abstract: A prime mover has a stationary assembly with a pair of opposite pole winding arrangements adapted for energization to establish a magnetic field, a non-ferrous end plate, and a rotatable assembly magnetically associated with the stationary assembly and having a part rotatably supported in the end plate. A shielding device on the end plate for providing a short-circuiting path to conduct a part of the flux of the magnetic field generally across the end plate between the winding arrangement pair upon the energization thereof with the shielding device remaining unsaturated.A method of operating a prime mover, a method of assembling and operating a prime mover, and a method of making a device and assembling it to a prime mover are also disclosed.

Abstract: Disclosed is an alternating current dynamoelectric machine which has damper plates of low resistivity material over the ends of the stator's tooth region to prevent axial flux from entering the stator's core. This invention also provides for cooling of the damper plates by the inclusion of cooling ducts within the damper plates. The flow of cooling fluid through the ducts cools the damper plates and also the end region of the dynamoelectric machine.

Abstract: A magnetic shield to reduce stator core end heating in an A.C. machine, which may also serve as a support structure for the end-turns of the stator windings, is formed of small-diameter iron wire circumferentially wound in a matrix of fiberglass impregnated with epoxy. The iron wire provides a low magnetic reluctance path in the circumferential direction at the core end. The higher reluctance path provided by the shield in the axial direction reduces the axial magnetic flux penetrating the core end. The wire and epoxy-impregnated fiberglass matrix may also constitute a high strength support for the end-turns.

Abstract: In an electronic watch powered by a battery, magnetic shield members made of an antimagnetic material are disposed in a watch movement to prevent the magnetization of the watch movement under the influence of a magnetic field outside of the watch, whereby watch hands continuously operate to indicate a correct time. The watch movement includes a bridge and a base plate, and the magnetic shield members are respectively mounted in a recess in the base plate and carried by the bridge so as not to contribute to a thickness of the watch movement.

Abstract: An improved apparatus is provided to cool the flux shields of dynamoelectric machines. In one embodiment of this invention, cooling fins are attached to a flux shield at localized areas of heating of the flux shield referred to as hot spots to reduce the temperatures there to acceptable levels. These fins may be provided with a tapered portion which minimizes the fluid losses associated with the flow of cooling gas over the fins. In another embodiment of the present invention, an annular rim, bored to provide cooling gas passages therethrough, is fixed to the flux shield along an inner portion thereof, to effect the transfer of heat from the flux shield to a flow of the cooling gas through the passages. Finally, in a third embodiment of the present invention, an electrically non-conducting annular baffle is disposed around the flux shield adjacent an inner surface thereof to direct a flow of cooling gas across the inner surface of the flux shield thereby cooling the same.

Abstract: A dynamoelectric machine, having a laminated stator core and having low impedance short-circuiting rings positioned between end flanges to minimize voltage differences between key bars. Circumferentially spaced key bars are used to effect assembly of the laminations and the end flanges. Circumferentially aligned recesses are formed in the key bars spaced inwardly from the end flanges, and each short-circuiting ring is positioned within aligned recesses. The short-circuiting rings comprise a plurality of arcuate ring segments and are formed of a material of high conductivity. Bolts secure the segments to the key bars.

Abstract: A creeping discharge and partial discharge-prevention means for a stator coil end of a rotary electric machine is disclosed. It includes an grounding electrode on an insulator of the stator coil end of the rotary electric machine, a first electrical stress grading coated layer on the insulator of the coil end including the end of the grounding electrode, a shield insulator made of insulation material around the first electrical stress grading coated layer including the end of the grounding electrode, a shield electrode electrically connected to the grounding electrode around the shield insulator, and a second electrical stress grading coated layer coated on the shield insulator including the end of the shield electrode.