| 摘要 |
PURPOSE:To obtain the wire dot head of low power consumption, which is free of magnetic interference, by a method in which the first bypass magnetic part is provided close to a permanent magnet and also the second bypass magnetic part is provided close to a magnetic erasor coil. CONSTITUTION:Most of the magnetic flux of a coil 5 pass through a closed loop A returning to a core 2 through the core 2, a plunger 6, and the second bypass magnetic part 31. The remaining of the magnetic flux pass through a closed loop B returning to the core 2 through the core 2, the plunger 6, an upper yoke 4, the first bypass magnetic part 32, and a lower yoke 3. Even when the magnetic flux passes through the suction portion of the adjacent drive units, no interference takes place, and even when the number of concurrently opening wires is increased, the current value necessary for opening is constant, thereby reducing the amount of power to be consumed. Since the magnetic flux for increment of suction forces by the permanent magnet 1 between the core 2 and the plungsr 6 can pass through the closed loop C by the first magnetic part 32, there is not increment of suction forces after being built in and therefore, the releasing current of the plunger can be reduced. |
