Electric motors with electronic commutation

Claim 2

An electric motor with electronic commutation, comprising: a rotor, a stator comprising n pairs of coils, each said pair comprising a driving coil, and a detector coil for providing a signal whose frequency and amplitude are proportional to the speed of said rotor, n being a whole number, the detection coil and driving coil of a said pair of coils being electrically offset by 90*, a voltage generator for providing a variable DC threshold voltage, dephasing means, having an input connected to said detector coils, for providing an output signal which is 90* out of phase with respect to the input signal from said detector coil irrespective of the frequency thereof, and amplifier means, having separate control inputs connected to said voltage generator and said dephasing means, for applying a voltage to said power windings when said dephased voltage exceeds said DC threshold.

Claim 3

An electric motor with electronic commutation, comprising: a rotor, a stator comprising n pairs of coils, each said pair comprising a driving coil, and a detector coil for providing a signal whose frequency and amplitude are proportional to the speed of said rotor, n being a whole number, the detection coil and driving coil of the same pair of coils being electrically offset by 90*, a resistor-capacitor integrating network, having an input connected to said detector coils, for delivering a signal which is 90* out of phase with the input signal and whose amplitude is independent of the speed of said motor, a voltage generator for providing a threshold voltage in direct relation to the difference between the amplitude of the output signal of said integrating network and the amplitude of a reference signal, and amplifier means, having control inputs respectively connected to the output of said voltage generator and to the output of said integrating network, for applying a voltage to said power windings when said output voltage from the integrating network exceeds said threshold.

Claim 4

An electric motor with electronic commutation, comprising: a rotor, a stator comprising n pairs of coils, each said pair comprising a driving coil, and a detector coil for providing a signal whose frequency and amplitude are proportional to the speed of said rotor, n being a whole number, the detection coil and driving coil of the same pair of coils being electrically offset by 90*, a resistor-capacitor integrating network, having an input connected to said detector coils, for delivering a signal which is 90* out of phase with the input signal and whose amplitude is independent of the speed of said motor, a voltage generator for providing a threshold voltage in direct relation to the difference between the amplitude of the output signal of said integrating network and the amplitude of a reference signal, and amplifier means, having control inputs respectively connected to the output of said voltage generator and to the output of said integrating network, for applying a voltage to said power windings when said output voltage from the integrating network exceeds said threshold.

Claim 5

Electric motor with electronic commutation according to claim 1, including a mechanical control for adjusting the voltage generator.

Claim 6

Electric motor with electronic commutation according to claim 2, having a regulating device into which the output signal of the dephaser is introduced, said regulating device being arranged to receive also said detector signal and to deliver a control signal which is applied to the voltage generator.

Claim 7

Electric motor with electronic commutation according to claim 2, including a current limiter interposed between the amplifier and the motor coil.

Claim 8

Electric motor with electronic commutation according to claim 1, further comprising a time delay device for delivering, successively, on starting of the motor, a positioning pulse to the detector coil to cause the displacement of the rotor to a position at 90* electrically with respect to the motor coil, and a starting pulse to the motor coil to cause starting of the rotor.

Claim 9

Electric motor wwth electronic commutation according to claim 6, further including a commutator, controlled by the time delay device, for dis connecting said time delay device upon starting of the rotor.

Claim 10

Electric motor with electronic commutation according to claim 1, wherein the stator comprises a ferrite cylinder on which n pairs of coils are wound so that the two coils of a same pair form annular coils of which the respective axes are displaced by an aNgle of pi /2n.

Claim 11

Electric motor with electronic commutation according to claim 2, comprising a single pair of coils.