Abstract: An optical encoder having a detector device including four light detectors, each formed of an elongated light sensitive surface. Free zones of this surface alternate with zones covered by an opaque layer arranged so that the cooperation of the light detectors with an encoder disc which leads to the delivery of output signals in phase quadrature, each light detector generating an output signal of a single phase.

Abstract: The present invention is concerned with a control circuit for an electric motor without a collector, of the type comprising a rotor magnetized in such a manner as to display at least one pair of magnetic poles, and a stator provided with a two- or a polyphase winding comprising several elementary coils of the same impedance, this circuit comprising electronic commutation means arranged for connecting selectively the elementary coils according to a cycle of successive supply states, to the terminals of a current source, under the effect of a commutation control signal, means for detecting the voltages appearing at the terminals of elementary coils or of groups of elementary coils and means for generating from the detected voltages, the commutation control signal.

Abstract: The stator of this flat magnetized-rotor motor comprises sets of pole pieces, arranged substantially radially, the sets being surrounded by corresponding electrical control coils. Separate yoke portions, having surface portions of axially symmetric design, are arranged in contact with the pole pieces of a corresponding set. The flat portions each consist of two sheet elements, forming between them an angle; the portions are inserted radially in the respective slots of a support portion of a stator element. With this arrangement it is possible to produce high-performance motors, at very low cost and whose dimensions in the radial direction are extremely small.

Abstract: A method is disclosed for manufacturing a synchronous electric motor which includes at least one flat annular rotor part which is magnetized so as to present at least one series of magnetic poles arranged along a flat annular zone of the rotor part. The rotor part is fixed by at least one rotor-supporting part on a shaft of the motor. The motor shaft is mounted for rotation with respect to at least one stator assembly which includes at least two stator parts. The stator parts include pole parts arranged so as to form, in their assembly, an air-gap in which are disposed the magnetic poles of the rotor part. At least one electric control coil is coupled with one or more pole parts.

Abstract: An actuation device having a moving member with a part magnetized perpendicularly to its displacement direction and two magnetic circuits having each, an air gap in which is arranged a portion of the magnetized part. Each magnetic circuit also has at least one electric energization coil coupled with it. The moving member is so arranged as to allow the magnetized part to effect a limited motion in both directions while the magnetic fluxes generated by the magnetized part are closed in the magnetic circuit outside the air gaps. The device provides a constant force on the limited path and has virtually no residual torque.

Abstract: In synchronous electric motors of the type having a movable multipolar permanent magnet member and a stator comprising magnetic circuits coupled to a control coil. The magnetic circuits form an air-gap of variable height in which the permanent magnet member is movably arranged.The improvement defines the height of the air-gap as a function of the position of the movable member, taking into account various design parameters of the motor, in order to obtain a purely sinusoidal variation of the torque produced in each phase of the motor by a constant control current.

Abstract: A synchronous electric motor includes least one flat annular rotor part, magnetized so as to present at least one series of magnetic poles arranged along a flat annular zone of the rotor part. The rotor part is fixed by at least one rotor-supporting part on a shaft of the motor. The motor shaft is mounted for rotation with respect to at least one stator assembly which includes at least two stator parts. The stator parts include pole parts arranged so as to form, in their assembly, an air-gap in which are disposed the magnetic poles of the rotor part. At least one electric control coil being coupled with one or more of the pole parts.

Abstract: A stator of the planar magnetized rotor motor according to the invention comprises groups of polar parts and at least two control coils. On each side of the rotor, each group of polar parts surrounded by a coil is arranged adjacent to the groups which are not surrounded by a coil. This arrangement makes it possible to increase the number of active poles of the stator, thereby increasing the motor torque, in a small size, economical, simple construction motor.

Abstract: The contact surface (8') is constantly urged against the commutator (9) by spring means. The brush material is progressively worn away, without changing the shape of the contact surface (8'), owing to the rotation of the commutator (9). A cylindrical slot (17) separates the outer portion (5') of the brush body (5) from the inner portion (5b) thereof. Thus, the contact surface (8') is kept separated from the cylindrical portion (16') of the outer surface of the brush body as long as the brush material is not worn away to reach the merging zone of the portions (5a) and (5b) of the brush body. This allows a substantial limitation of the risk of sparking between the brush body and the commutator to be achieved, thus avoiding deposit of a carbon layer onto the peripheral surface of the commutator.

Abstract: A multipolar magnetization device comprises at least one electric power source, at least two distinct current pulse generating devices and several portions of electric conductors respectively connected to at least four of said conductor portions for producing a given magnetic field portion. The magnetization device is arranged for creating a series of magnetic field portions of successive alternating polarities for producing in a magnetizable body a corresponding series of magnetized zones.

Abstract: An electric motor which delivers a high torque per Ampere-turn and a high power rate and acceleration of the rotor. Maximum torque per Ampere-turn is accomplished by setting a minimum air-gap width in the range defined by the relationship 0.389 P+1.4.ltoreq.P/E.ltoreq.0.706 P+1.85, with P being the space in millimeters between the centers of the magnetic poles of like polarities of a multipolar permanent magnet arrangement disposed on the rotor and between the centers of regions of minimum width of the air-gap, and E being the width in millimeters of the air-gap. The air-gap refers to the space between opposite parts of permeable magnetic material and thus defines the entire space in which a permanent magnet is placed.

Abstract: In order to form, on opposite plane surfaces of a magnetizable plate portion of a part (62), a series of magnetized areas, the device comprises a frame (68) wherein two support parts (64, 65) made of a material having a high magnetic permeability presenting respectively plane polar surfaces are arranged in parallel facing each other and are coupled with portions of electric conductors arranged so as to generate between the polar surfaces of the opposite support parts magnetic field producing the magnetization of said areas. One of the support parts (65) is displaceable with respect to the other one (64) and with respect to the frame (68), perpendicularly to the polar surfaces so as to bring close and to spread apart said polar surfaces with respect to the flat portion of the parts to be magnetized.

Abstract: The present invention relates to a synchronous electric motor of the type comprising at least one rotor part of substantially annular disc form, magnetized axially so as to present, on its opposite flat faces, a series of magnetic poles of alternate polarities, disposed regularly along an annular zone of each face, the rotor part being mounted on a rotary shaft, the motor also comprising an assembly of several elementary magnetic circuits which are insulated magnetically from one another, an annular electric energizing coil which is coupled with the said assembly of elementary magnetic circuits, each of said circuits providing an air-gap and the assembly of these air-gaps forming an annular region in which are disposed the magnetized zones of the rotor part, each of the elementary magnetic circuits having substantially flat C-configuration, being placed substantially radially with respect to said rotor shaft and having a central opening in which is placed said annular coil.

Abstract: The present invention relates to a synchronous electric motor of the type comprising at least one rotor part, substantially of annular disc form, magnetized so as to present on at least one of its opposite planar surfaces at least one series of magnetic poles of alternating polarities, disposed regularly along at least one annular zone, said rotor part being mounted on a rotatable shaft, the motor additionally comprising at least one assembly of several elementary magnetic circuits of a magnetically permeable material and at least one annular electric energizing coil coupled with said assembly of magnetic circuits, each of said circuits having at least one air-gap, and all of said air-gaps being arranged for cooperating with the said magnetic poles of an annular zone of said rotor part, each of said elementary magnetic circuits comprising at least two rectangular and essentially flat pole parts, which are arranged substantially radially with respect to said shaft of the rotor.

Abstract: A polyphase synchronous motor having a relatively large number of poles, constructed for substantial elimination of all significant harmonics. Harmonics are eliminated by dividing the motor into two symmetrical groupings, each a complete motor, then rotating one grouping relative to the other by an angle .pi./h electrical degrees, where h is the order of the harmonic being suppressed. Also, with a permanent magnet disc rotor, the magnet poles on one face of the disc can be rotated relative to those of the other face in the same manner, to suppress a harmonic.

Abstract: A cylindrical, ironless, self-supporting rotor coil for use in an electrical dc-machine is disclosed. The coil is formed by at least one layer of wire, the wire having a conductive core, an insulating layer surrounding that core and an outer layer comprising a supporting material capable of being softened and subsequently solidified to make the coil self-supporting. The outer layer of the wire is at least in part electrically conductive in order to reduce the production of sparks in the commutator of the dc-machine.

Abstract: A method is disclosed for braking a two-phase synchronous electric motor of the magnetized rotor type, driving a mechanical device. By this method the current supplied to the electric motor is controlled as a function of the actual position and the actual angular speed of the rotor within the braking period on the basis of information derived from the motor itself without additional detector devices. Perfectly proportioned braking is achieved taking into account individual motor and load characteristics and their possible variation, for example with temperature.

Abstract: The motor according to the invention comprises a disc-shaped rotor with multipolar permanent magnetization along an annular area and a stator comprising a plurality of magnetic circuits (9, 10, . . . ) arranged so that the magnetic field is comprised within the two cylindrical face portions based on the magnetized annular area and located on either side of the rotor. Means for compensation of the harmonics of the current-free torque and of the current torque are provided, as well as the arrangement of magnetic pick-ups (25, 26). The invention applies to industrial synchronous motor which may operate as stepping motors.

Abstract: An electric stepper motor of the type comprising an axially magnetized rotor disc and a plurality of elemental magnetic stator circuits is disclosed. Each elemental circuit is formed of two U-shaped portions arranged opposite each other, one of each U being in contact with the opposite U-end and the second U-end being spaced from the opposite one to form an air gap for the rotor disc, the centers of the ends forming the airgap being angularly shifted with respect to each of the U-ends in contact with each other so as to compensate the third and/or fifth harmonics in the torque due to the driving current.

Abstract: The present control device is used in connection with a diphase or polyphase stepper motor in which the coils of two phases (b.sub.i, b.sub.j) are not simultaneously supplied with driving current. A commutation circuit CC is adapted to connect the coils to a voltage source V or to a detection circuit CD. A logic control circuit CL.sub.1, CL.sub.2, CL.sub.3, itself controlled by a clock signal source G.sub.1 and by a generator of programmed control pulses PG, supplies control signals to said circuits CC and CD. The control device provides a feedback control of the motor as a function of the speed and the position of the rotor at various instants of the control cycle in accordance with a predetermined program so as to assure perfectly reliable operation of the motor with a minimum of electric energy even for motors manufactured with rather wide manufacturing tolerances.