CONTROLLING METHOD FOR BRUSH URGING AMOUNT

摘要

PURPOSE:To control an accurate brush urging amount inexpensively with a simple structure by collecting the brush urging amount as the variation in the rotating speed of a motor by using as a brush drive motor a high resistance squirrel cage induction motor. CONSTITUTION:A brush 2 is rotatably driven by a motor 3, which employs a high resistance squirrel cage induction motor. This brush 2 is also raised or lowered by a motor 4, thereby controlling the urging amount to the material. A pulse oscillator 9 generates pulses of the number proportional to the brush rotating speed. This pulse is inputted to 2-stage setting preset counter 10, which counts the number of pulses. The magnitude of the brush urging amount is discriminated by the counter 10, with the result that the brush urging motor 4 is controlled in response to the consequence.