| 摘要 |
<p>PURPOSE:To prevent temperature from rising when air quantity is reduced, by rotating a brush holder around a commutator in the same direction as that of the rotation of the commutator, along with the reduction of air quantity flowing into a motor or along with the increasing rotational frequency of the motor. CONSTITUTION:Air quantity flowing into a motor 21 is sensed by an air quantity sensor 36, and the output is fed to a controller 39. An electromagnet 35 is driven by the controller 39 based on the output from the air quantity sensor 36, and a brush holder is rotated in the same direction as that of the rotation of a commutator along with the reduction of the air quantity flowing into the motor 21. Besides, a rotational frequency sensor for sensing the rotational frequency of the motor 21 may be used in place of the air quantity sensor.</p> |
