A timepiece movement includes a movement case, a drive mechanism, a time mechanism driven by the drive mechanism, a day mechanism, and a day adjustment mechanism. The day mechanism is driven by the time mechanism through a frictional engagement therebetween. Once a torque generated by the day adjustment mechanism overcomes the frictional engagement, the day mechanism is permitted to be driven by the day adjustment mechanism. Therefore, an indicated day of the timepiece movement can be adjusted without pulling out of a day adjustment knob or an actuating shaft of the day adjustment mechanism.

A method for determining an error in the angular position measurement of a timepiece motor having one or more phases, including: detecting (3) each instant (14) when the value of one of the back electromotive forces is zero, storing (4) a time corresponding to each detected instant, measuring (5) several time intervals between two instants (14) detected in the same revolution of the motor, comparing (6) the measured time intervals to reference time intervals to deduce the reference intervals to which they correspond, and determining (7) an angular position measurement error if the measured intervals do not correspond to the expected reference intervals. The invention also relates to a method for correcting the angular position measurement. Also, a determination and correction system for implementing the methods and a timepiece including such a system.

A motor drive unit for driving a direct current electric motor including a moving part equipped with permanent magnets. The motor drive unit, which is powered by a voltage supply source, includes a switch circuit, an inductor circuit and a capacitor circuit including a set of capacitors. By selectively opening and closing the switches of the switch circuit, a series of consecutive low energy pulses can be generated such that the power consumption of the motor drive circuit is minimized.

A motor drive unit for driving a direct current electric motor including a moving part equipped with permanent magnets. The motor drive unit, which is powered by a voltage supply source, includes a switch circuit, an inductor circuit and a capacitor circuit including a set of capacitors. By selectively opening and closing the switches of the switch circuit, a series of consecutive low energy pulses can be generated such that the power consumption of the motor drive circuit is minimized.

A continuously rotating electric motor includes a rotor provided with permanent magnets and a stator formed by two coils in which, when the rotor is rotating, two induced voltage signals (U.sub.B1 and U.sub.B2) are respectively generated, which signals have an electric phase shift φ where 5°≤φ≤90°, preferably 30°<φ<65°. The control device includes a circuit for detecting intersection times (T.sub.C) at which values of the two induced voltage signals are substantially equal. The control device is arranged to generate electric driving pulses to rotate the rotor, which are respectively initiated at initiation times determined by respective intersection times, and such that the electric driving pulses can be applied to the two coils arranged in series. Preferably, the control device is arranged such that the initiation times of the electric driving pulses occur directly after detections of corresponding intersection times.

A continuously rotating electric motor includes a rotor provided with permanent magnets and a stator formed by two coils in which, when the rotor is rotating, two induced voltage signals (U.sub.B1 and U.sub.B2) are respectively generated, which signals have an electric phase shift φ where 5°≤φ≤90°, preferably 30°<φ<65°. The control device includes a circuit for detecting intersection times (T.sub.C) at which values of the two induced voltage signals are substantially equal. The control device is arranged to generate electric driving pulses to rotate the rotor, which are respectively initiated at initiation times determined by respective intersection times, and such that the electric driving pulses can be applied to the two coils arranged in series. Preferably, the control device is arranged such that the initiation times of the electric driving pulses occur directly after detections of corresponding intersection times.

A timepiece movement includes a photovoltaic cell which is attached to the upper surface of a support plate, preferably by adhesive bonding. On the other side of the cell, on its lower surface, the support plate is provided with a plurality of nuts. An electrical module including a flat surface is attached to the support plate with the nuts. The module is provided with several openings whose position and dimensions correspond to those of the nuts, so that the nuts pass through the openings, allowing the flat surface of the module to be placed in contact with the support plate. The module is secured to the support plate by screws, screwed into the nuts. The connection via the nuts secures the photovoltaic cell to the electrical module and ensures shock resistance, without requiring a lateral support.

A DC motor including a continuous rotation rotor; a first inductor characterized by first parameters; a second inductor characterized by second parameters; a voltage supply unit; a measurement unit for detecting time instants when a first induced voltage in the first inductor equals a second induced voltage in the second inductor; and a control unit for controlling the application of drive voltage pulses to the inductors. The rotor faces first the second inductor before facing the first inductor when being rotated. At least one of the second parameters is selected different from a corresponding parameter of the first parameters such that a maximum induced voltage in the first inductor is greater than a maximum induced voltage in the second inductor. The control unit is arranged to trigger each of the drive voltage pulses after a detection of an equal induced voltage in the first and second inductors.

A DC motor including a continuous rotation rotor; a first inductor characterized by first parameters; a second inductor characterized by second parameters; a voltage supply unit; a measurement unit for detecting time instants when a first induced voltage in the first inductor equals a second induced voltage in the second inductor; and a control unit for controlling the application of drive voltage pulses to the inductors. The rotor faces first the second inductor before facing the first inductor when being rotated. At least one of the second parameters is selected different from a corresponding parameter of the first parameters such that a maximum induced voltage in the first inductor is greater than a maximum induced voltage in the second inductor. The control unit is arranged to trigger each of the drive voltage pulses after a detection of an equal induced voltage in the first and second inductors.

Timepiece movement fitted with an electromagnetic transducer comprising at least one coil and a rotor formed of a central shaft, of two magnetic plates that are mounted on the central shaft and of a plurality of bipolar magnets which are axially polarized and mounted on at least one of the two magnetic plates, said at least one coil penetrating at least partially into a circular space which is defined by the rotor between its two magnetic plates and left free by this rotor. The central shaft comprises a pinion which engages with a wheel of the timepiece movement, this pinion being arranged between the two magnetic plates and said wheel being partially arranged between the two magnetic plates, in an angular sector of the circular space that is left free by the electromagnetic transducer, so as to engage with the pinion. Advantageously, said wheel has a roller that is almost or entirely non-conductive and a non-magnetic staff.