Electric motor with rotational speed regulation

Claim 1

An electric motor having rotational speed regulation and comprising a rotatably journaled cylindrical rotor (10) including a permanent magnetic material (11); a stator (14) having at least one exciting or driving winding (16, 18); rotor position detecting means; and a control and regulating circuit, said rotor position detecting means comprising at least one sensor or transducer unit (22) generating an output signal which varies synchroniously with the instantaneous position of said rotor, said output signal being supplied, to a two input multiplier unit (40 or 42) as one input signal (y) thereof, said multiplier unit multiplying the signal with a factor determined by the other input signal (x) of said unit, whereafter said multiplied signal is supplied to said exciting winding through a power amplifier (54 or 56), CHARACTERIZED in that said sensor or transducer signal also is supplied to a pulse generator (44 or 46), generating a pulse output signal having a pulse repetition rate which is uniquely associated with and directly determined by the period of said varying sensor or transducer signal, and in that said pulse signal is supplied to a frequency-to-voltage converter unit (48) which provides an output signal being supplied to a differential amplifier (50) as one input signal thereof, the other input signal being a reference voltage, and the output signal of said amplifier being supplied to said multiplier unit as said other input signal (x) thereof.