초록 ▼

A speed-controlling circuit for controlling the rotational speed of a D.C. electric motor in which the electric current is supplied to the D.C. motor through a switching circuit which is periodically open for a predetermined fixed time interval. The switching circuit is controlled by electrical puls

A speed-controlling circuit for controlling the rotational speed of a D.C. electric motor in which the electric current is supplied to the D.C. motor through a switching circuit which is periodically open for a predetermined fixed time interval. The switching circuit is controlled by electrical pulses having a repetition rate which varies in dependence upon the rotational speed of the motor, whereby to periodically interrupt the supply of current to the motor.

대표청구항 ▼

A speed-controlling circuit for controlling the rotational speed of a D.C. motor by selectively connecting the motor to a power supply circuit and disconnecting the motor from the power supply circuit, said speed-controlling circuit comprising: switching circuit means for controlling the supply of e

A speed-controlling circuit for controlling the rotational speed of a D.C. motor by selectively connecting the motor to a power supply circuit and disconnecting the motor from the power supply circuit, said speed-controlling circuit comprising: switching circuit means for controlling the supply of electric current to the motor, said switching circuit means being connected to the power supply and to the motor and having an ON state causing the motor to be connected across the power supply circuit and an OFF state causing the motor to be disconnected from the power supply circuit; transducer means coupled with the motor and responsive to the rotational speed thereof to produce an electric pulse for each motor revolution, the magnitude of said electric pulses increasing with increased motor speed; threshold circuit means connected to the transducer means to receive therefrom said electric pulses and including means for providing a threshold electric level, means for comparing the magnitude of each received electric pulse with said threshold electric level and means for providing a control pulse in response to each electric pulse whose magnitude exceeds the threshold electric level; and timing circuit means connected to the threshold means to receive said control pulses therefrom and responsive to each received control pulse to place the switching circuit means in the OFF state thereof for a time interval of constant, fixed duration which is less than the duration of a motor revolution, said timing circuit maintaining the switching circuit means in the ON state except during said time intervals of constant, fixed duration, wherein said timing circuit means further comprises a capacitor, means connected to the capacitor and to the threshold circuit means for charging the capacitor to a selected constant potential in response to each control pulse provided by the threshold means, means for discharging the capacitor at a selected constant rate; and means connected to the capacitor and to the switching circuit means for placing and maintaining the switching circuit means in the OFF state thereof while the potential on the capacitor exceeds a selected potential level and for placing and maintaining the switching circuit means in the ON state thereof while the potential on the capacitor is below said selected potential level; whereby current is at first supplied to the motor without interruption until the motor attains a selected speed at which the electric pulses from the transducer means exceed the selected threshold level, and then the supply of current to the motor is shut off for a constant, fixed time interval during each revolution of the motor, but said constant, fixed intervals occur at a rate proportional to the motor speed, to thereby quickly reach and then maintain a selected operational revolution speed.