| 摘要 |
PURPOSE:To enable to control the rotating speed of a motor without interposing a resistor by forming a multipolar multibrush structure in a fan driving motor and selectively varying the number of conductive brushes. CONSTITUTION:When a switch S1 is closed, brushes BR1 and BR4 are conducted to start operating of a fan driving motor M. When a switch S2 is then closed, the brush BR2 is also conducted, and since the fan driving motor M is operated in the state that three brushes are conducted, the rotating speed of the fan is accelerated. When the switch S3 is further closed, the brush BR3 is also conducted, and the fan driving motor M is operated in the state that the four brushes are conducted, and the rotating speed of the fan is further increased. In this manner, the rotating speed of the motor can be controlled simply without interposing a resistor. |
