| 摘要 |
PURPOSE:To make it possible to detect the life of a brush preliminarily by providing a contact piece having a spring force at a brush holder installing plate so as to let it contact with the pigtail of the brush or a contact piece fixed at the brush when the brush is almost ending its life. CONSTITUTION:A brush 4 is contained in a brush holder 1 fixed at a brush holder installing plate 2, and it is pressed to a rectifier 5 by a spring 3. A pigtail 6 is connected with the brush 4, and the other end is connected with the holder 1. A lead 7 from the holder 1 is connected with a positive electrode, while another lead 8 is connected with earth. In this constitution, a brush life detecting part is formed of a contact piece 9 fixed at the brush 4, a contact piece 10 fixed at the installing plate 2, and a lead 11 connected with the contact piece 10. If the brush 4 is abraded by rotation of a motor, the contact piece 9 gets closer to the rectifier 5 to be connected with the contact piece 10 when the brush is ending its life, and a lamp 12 is lighted. The life of a brush can thus be detected.
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