| 摘要 |
PURPOSE:To make it possible to prolong the life of a brush by providing the constitution, wherein the second brush of the second motor is brought in the ungrounded state when the third brush of the first motor is connected to the second brush of the second motor, and the grounded state is obtained when the third brush is connected to a power supply. CONSTITUTION:Four brushes 4-7 are provided in a first DC motor 3a. The first brush 4 and the third brush 6 face to each other, and the second brush 5 and the fourth brush 7 face to each other. Two brushes 8 and 9 in a second DC motor 3b are so arranged as to face to each other. When the DC motors 3a and 3b are connected in parallel and a voltage is directly supplied from a power supply B, the normal operation is performed in use. The brushes 4-9 are designed in this way. Therefore, even if the DC motors 3a and 3b are connected in parallel, the commutation of the brushes 4-9 can be made excellent. Therefore, even if the brushes are connected in series, the low voltage is supplied from the power supply B and the rotational speed is decreased, the commutation of the brushes 4-9 becomes excellent. As a result, the life of each brush can be made long. |
