Patent ID: 6628893
Filing Date: 2003-09-30
Classification: H02K,H02P

Abstract:
A direct current motor rotation control apparatus configured to control rotational operations of a direct current motor including a stator, a rotor with a rotation shaft and rotor coils, a commutator connected to the rotor coils, and a pair of electrode brushes in sliding contact with the commutator and configured to supply electric power from the commutator to the rotor coils to change a state of a direct current drive voltage to the rotor coils, comprising:at least one rotation detecting brush contacting the commutator at a different axial position from an axial position contacted by the pair of electrode brushes and configured to detect a signal on the commutator indicative of an operation of the direct current motor; a motor driving circuit configured to drive the direct current motor by applying the direct current drive voltage to the pair of electrode brushes; a reference voltage generating device configured to generate a reference voltage in proportion to the direct current drive voltage; a comparator configured to compare the signal detected by the at least one rotation detecting brush with the reference voltage generated by the reference voltage generating device and to produce a pulse train of pulse period corresponding to a rotational speed of the direct current motor as an output comparison signal; and a motor control circuit configured to adjust the direct current drive voltage based on said output comparison signal, thereby to control an operation of the direct current motor.