| 摘要 |
PURPOSE:To prevent electric current to be fed to an armature coil by brushes from being short-circuited, by a method wherein a plurality of rows of commutator segments are arranged in the rotational direction and further brushes are divided and arranged confronting each row of commutators. CONSTITUTION:When brushes 1a, 1b are respectively arranged in contact with commutator segments 2a(4) and 2b(4), the commutator segment 24(b) only is connected to work effectively. Then, in case that the brushes 1a and 1b come in con tact with (3) and (4) of the commutator segments 2a, 2b at the same time, no electric current is sent to an armature coil via the commutator 2a(4) because the commutator 2a(4) is of dummy even if the brush is communicated with the commutator segnet 2a(3). Diodes 8, 8' are provided so that no electric current is mutually communicated between the divided brushes 1a and 1b and between the brushes 1a' and 1b' on the other side. Accordingly, between the brushes 1a and 1b, the armature coil 3' is not made a closed loop due to the action of the diodes, and the short-circuiting of the armature coil due to the brushes is not generated. |
