Eta Sa Fabriques D'ebauches

Yves Guerin

Rene Besson

Rudolf Bugmann

Luciano Antognini

Transducer, in particular clockwork driving motor, comprising a stator (2) formed of two stator parts (16 and 26) and three cores (18, 19, 20) connecting respectively three magnetic poles (28, 29, 30), defined by the first stator part (16), to the second stator part (26) used to close the magnetic paths of the transducer. The coils (22 and 24) are used to supply the transducer to drive in rotation respectively the two rotors (4 and 6). The coil (23) is connected to detection means (72) used for detecting the rotation of one or other of the two rotors (4 and 6), and in particular, for detecting zero crossing of the induced voltage (or similarly of the induced current) in the coil (23). Detection of zero crossing of the induced voltage is used to provide input signals to the supply means (70) to control driving of the rotors (4 and 6) in an efficient and reliable manner, in particular in a rapid or continuous operating mode, whether in a forward or backward rotational direction.

Electromechanical transducer comprising two rotors having permanent

The method includes applying to the coil (3) of the motor (2) driving pulses having alternately a first and a second polarity, supplying the coil (3) with a determined quantity of electric energy during each driving pulse, detecting, after each driving pulse, the rotation or non rotation of the rotor of the motor (2) in response to said driving pulse, and adjusting said determined quantity of electric energy as a function of said detection. In order to further reduce the quantity of electric energy consumed by the motor, the method is characterised in that the adjustment of the quantity of electric energy supplied to the coil (3) is effected separately for the driving pulses having the first polarity and for the driving pulses having the second polarity.

Method and device for controlling a stepping motor

The purpose of the invention is the realization of a motor assembly formed from a stepping motor and its control circuit capable of operating at a maximum speed substantially greater than that obtainable with comparable existing assemblies. This is effected by substituting for the single coil or for each coil of a known motor two or more windings and adopting a control circuit which connects the windings in series or parallel according to whether motor drive pulses of low or high frequency are applied thereto. The total number of winding turns and the sum of the resistances of the windings are preferably chosen to be equal respectively to the number of turns and the resistance of the coil which they replace in order to avoid basic modification of the characteristics and performances of the motor when operating at low speed. When the windings are connected in parallel their resistance and equivalent self-inductance are less than that of a single coil. The energy transfer from the voltage source to the rotor of the motor is increased and facilitated and the maximum speed of the motor is considerably increased.

Stepping motor assembly

The device includes two driving circuit (C.sub.1, C.sub.2) each of which includes six power transistors (T.sub.11 -T.sub.16, T.sub.21 -T.sub.26) that are connected in pairs into three parallel circuit branches. A first coil (B.sub.11) of one of the motors and a first coil (B.sub.21) of the other are, on the one hand, both connected to the junctions of the transistors of one of the branches of one of the driving circuits (C.sub.1) and, on the other hand, respectively connected to the junctions of the transistors of the two other branches of this circuit. The same applies for the second coils (B.sub.12, B.sub.22) of the motors and the other driving circuit (C.sub.2). The various transistors are controlled so that the two coils of the same motor simultaneously receive the current pulses which are needed to make it turn but by preventing the simultaneous application of current pulses to a coil from one of the motors and to a coil from the other. This arrangement makes it possible to save four transistors and two output terminals on the integrated circuit used to control the motors.

Control device for two bidirectional step motors

The method involves supplying to the motor drive pulses generated by a control circuit, determining by means of a measurement circuit a physical magnitude representative of the motion of the rotor, interrupting the drive pulse at a given instant defined by a calculating circuit according to the time taken by the physical magnitude to reach, in a comparator, a reference level, controlling by means of a missed step detecting circuit whether or not the rotor has effected a step, retrieving if need be a non-effected step, summing the number of missed or non-effected steps in a counting circuit, and modifying in a reference circuit the reference level depending on the number of steps that have been missed in a given period of time. The device for putting this method into operation enables the motor to operate under optimal security and energy consumption conditions and can be used to advantage in timepieces.

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St. Louis, France

Yves Guerin