| 摘要 |
PURPOSE:To suppress the spark discharge of a brush of a DC motor by setting the applied voltage for driving the motor to a low voltage synchronously with the switching of a commutator by the brush. CONSTITUTION:An encoder 2 coupled directly to a DC motor 1 outputs a pulse train for positioning the brush of a commutator from an output terminal a1, and outputs a reset pulse at one revolution from an output terminal a2. A counter 3 counts the number of pulses of the pulse train after the reset pulse is inputted. A comparator 4 generates an output pulse when the value of the counter 3 becomes the set value of a high period setter 7 or a low period setter 8. FF6 becomes high level at the output terminal Q and a terminal Q' whenever the pulse is inputted. A constant-voltage circuit 1 applies the output of the high voltage or low voltage to the motor 1 in response to the output of the FF6. |
