| 摘要 |
In a method and apparatus for regulating the rotational speed of a motor having a rotor with magnetic poles and a stator with at least two coils, wherein during a first operational mode the sinusoidal voltage included in a first of the coils is digitized to produce first and second streams of rectangular pulses, the first pulse stream being compared with a reference frequency pulse signal as regards width and phase to generate accelerating or braking driving pulses supplied to the second coil, the second pulse stream being monitored to determine the rotational speed of the rotor and a second operational mode being instituted whenever the rotor speed falls below a predetermined value, in said second operational mode the rotor speed being accelerated through the application of driving pulses alternately to the first and second coils, the improvement wherein, following the switchover from the self starting mode to the nominial running mode of operation, during a transitional period for a specified time interval, the first pulse stream is compared with the reference pulse signal at a monitoring frequency that is a multiple of the monitoring frequency employed during the nominal running mode of operation after expiration of the specified time interval.
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