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.

Abstract: This control device is used in connection with a motor comprising a magnetic rotor and at least two magnetic stator circuits coupled with respective coils (b.sub.1,b.sub.2). A logic circuit (21) is arranged to alternatively feed drive pulses to both coils and to connect the coil which is not fed to a detection circuit (24, 25) the output of which is connected to the logic circuit in order to determine the duration of a feed pulse or to trigger a new feed pulse. This control device allows the current consumption of the motor as well as the locking torque to be reduced, since the servo control obtained insures the rotor positioning in case an important disturbance should occur.

Abstract: A polyphased stepping motor for the direct driving of the second or minute pin in a clockwork. The motor comprises a disc shaped rotor (1) axially magnetized so as to have 2N alternating poles and at least two stator members (2, 3) each made by a magnetic circuit with gap and command coil (6, 7). The magnetic circuit is formed by one or two U-shaped members coupled with the said coil. The arrangement is such that the number of steps per command current period be 60 m/N. The invention also applies to motors for quartz clocks.

Abstract: A movable magnet 1 turns in the air-gap formed by pole pieces 3', 4' of a stationary magnetic circuit 2. The magnetic circuit 2 is formed as one piece, and has a deformable connection portion 6, the magnetic properties of which are greatly inferior to those of the remainder of the circuit which enables the branches to move apart for introduction of the coil during assembly. This arrangement facilitates manufacture, while not limiting the diameter of the coil to the dimensions of the air-gap and maintaining a high degree of precision of the air-gap.

Abstract: A device for measuring a characteristic magnitude of the operation of a timepiece movement is disclosed, in which measuring pulses are generated in response to vibrations of the movement for measuring the time intervals between vibrations reflecting the operation of the movement. The generation of measuring pulses is allowed only within a short window of constant duration following a blocking period which starts after the occurrence of a measuring pulse and has a duration depending on the duration of the penultimate preceding time interval between measuring pulses.

Abstract: The invention relates to a direct current micromotor having an iron-free rotor comprising a coil support in the form of a disc and a cylindrical coil 10 fixed at one of its ends to the periphery of this disc, the coil support bearing the collector segments and being constructed in the form of a printed circuit board 11. The collector segments are constituted by circular segments of conducting material 12 having a radial extension 13 which extends to the periphery of the disc. A peripheral connection sector 14 is separated from the sector 12 by an insulating zone 15.This arrangement enables damage to the brushing surface of the collector brushes to be avoided during manufacture, such damage being caused by a coating of welding flux or by inappropriate heating.

Abstract: A miniature electric stepping motor comprising a magnetized rotor adapted for rotation in the air gap of a stationary magnetic circuit having an electric excitation coil connected to a control device. The control device cmprises means for applying to the excitation coil control impulses of a first polarity and of an amplitude and a width such that the rotor rotates in a first direction of rotation from one stable equilibrium position to the next one and means for applying to the excitation coil, upon an outer control, starting from each stable equilibrium position, first a pre-impulse of said first polarity and subsequently a control impulse in the reverse direction, having a polarity opposite to the said first polarity, such that the rotor, after having reversed its direction of rotation, moves in the reverse direction of rotation until it reaches the stable equilibrium position following that at which the said pre-impulse has been applied.

Abstract: A printing device for chronocomparators comprising a striker, an ironless cylindrical coil mounted for rotation in an air gap of a magnetic circuit and connected to the striker, the magnetic circuit being formed by a permanent magnet placed inside the coil and an outer part of magnetically permeable material surrounding the coil. The coil is connected through spiral springs to a source of electric control pulses. The spiral springs provide a return force for bringing the coil back to a rest position in the absence of a control pulse. A cylinder with a helical rib is placed to be stricken by the striker and a recording strip is inserted between the striker and the said cylinder.

Abstract: Device for controlling a monophase rotary step-by-step motor supplying electric control pulses to the winding of the motor, comprising means for detecting the variation of the current passing through the motor winding at each control pulse, this detection means including means of interrupting the control pulse when a minimum appears in the current passing through the winding.

Abstract: An assembly comprising an escapement timepiece pallet anchor and its frame is disclosed, wherein the pallet anchor is in the form of one piece of plastics material having three arms and is rotatably mounted on the frame. The assembly comprises means for limiting the angle of rotation of the pallet anchor, which means include at least one auxiliary portion on the piece forming the pallet anchor and at least one part rigid with the frame disposed to cooperate with said auxiliary portion.

Abstract: A multipolar step motor having a rotor with N pairs of alternatively positive and negative magnetic poles arranged thereon with a regular angular spacing therebetween. The motor has two polar members defining an air gap within which the rotor is disposed, at least one of the polar members being configured to define N alternations of the distance between the said member and the rotor. The elements defining the said alternations comprise two groups in which the elements are equally spaced by 2.pi./N, the two groups being angularly spaced by an angle of .pi./4N one with respect to the other.

Abstract: A direct-current micromotor is disclosed which comprises a rotor bearing a motor winding, the rotor being arranged for rotation between a core part and a mantle part of a stator structure. The core part comprises a permanent magnet and the mantle part is made of magnetically conductive material. The motor winding is fed through a commutator comprising a collector and associated brushes. At least a part of the surfaces of the stator facing the rotor winding are provided with an electrically conductive coating to reduce the height of the voltage peaks occuring during the commutation.

Abstract: An electric actuating device for producing limited angular displacements comprising an ironless cylindrical coil mounted for rotation in an air gap of a magnetic circuit, the magnetic circuit being formed by a permanent magnet placed inside the coil and an outer part of magnetically permeable material surrounding the coil. The coil is connected through spiral springs to a source of electric control pulses. The spiral springs provide a return force for bringing the coil back to a rest position in the absence of a control pulse. Means are provided for limiting the angle of rotation of the coil.

Abstract: An apparatus for measuring the rate of a watch is disclosed including a sensing device for the signals produced by a watch to be checked, a selecting and pulse shaping circuit, and comparator means for comparing the repetition frequency of the measuring pulses with the frequency of standard pulses. The selecting and pulse shaping circuit is designed to constitute a monostable multivibrator the period of which is automatically adapted to the period of the signal to be measured. The selecting circuit is unsensitive to secondary and disturbing noise signals during a very high percentage of the time interval corresponding to the period to be measured and allows the checking of watches having frequencies between about 1 Hz and 32 kHz.