| 摘要 |
PURPOSE:To detect when to change the brush automatically and to attempt the work-saving in maintenance by detecting the movement due to the abrasion of a brush with a cam-operated switch. CONSTITUTION:A brush 1 is pressed by a spring 11 to a collector ring 10. A brush hole 4 is provided to the brush 1. An insulating bar 5 provided with a contact 7 is pressed to the brush hole 4 by a presser bar spring 6. In the normal limit of the brush 1 the brush hole 4 is so shallow as shown in 4b and so deep as shown in 4a in the abraded position that as the abrasion of the brush 1 goes on, the position of the contact 7 provided to the insulating bar 5 will move and the abrasion of the brush 1 can be electrically detected. |
