Braking method, braking circuit and speed control apparatus for a DC motor

A braking circuit for a pulse-driven DC motor comprising:

• a capacitor connected to a winding of said DC motor;
• a diode interposed between said capacitor and said winding so as to charge said capacitor with a counter electromotive force generated in said winding after the feeding of a driving pulse to said winding;
• and
• a switching element interposed between said capacitor and said winding so as to feed said counter electromotive force charged in said capacitor to said winding;
• wherein said capacitor discharges its electrical charge and said discharged electrical charge is fed to said winding with a reverse polarity with respect to said driving pulse by switching on said switching element in the absence of said driving pulse so that plugging is applied to said DC motor.

A speed control apparatus for a pulse-driven DC motor comprising:

• a rotational speed detecting device for detecting the rotational speed of said DC motor;
• a circuit for generating a driving pulse whose duty ratio corresponds to a difference between a speed setting signal for said DC motor and a detected speed signal from said speed detecting device;
• a capacitor connected to a winding of said DC motor;
• a diode interposed between said capacitor and said winding so as to charge said capacitor with a counter electromotive force generated in said winding after the feeding of a driving pulse to said winding;
• a switching element interposed between said capacitor and said winding so as to feed said counter electromotive force charged in said capacitor to said winding;
• and
• a switching element control circuit for switching on said switching element at a proper time.