| 摘要 |
PURPOSE:To prevent a movable contact of a magnet switch from clattering at the time of starting by a method wherein the opening and closing of a current- supplying circuit for an attracting coil of the magnet switch is controlled by the current supply condition of a motor circuit. CONSTITUTION:When a key switch 1 is closed, the attracting coil 4 and a holding coil 5 of the magnet switch 3 are supplied with current a movable iron core 12 is moved leftwards against a spring 13 by the magnetomotive forces of the coils 4, 5 and the movable contact 9 is brought into contact with fixed contacts 8a, 8b. At this time, if the voltage at a terminal S is higer than the Zener voltage of a Zener diode ZD15, a transistor Tr14 is turned ON and a large amount of current is supplied from a battery 7 to a motor 11. After the contacts 9, 8a, 8b are closed, the voltage at a terminal M becomes lower than the battery voltage, and when the voltage impressed on the diode ZD15 becomes lower than the Zener voltage, the transistor Tr14 is turned OFF to stop the supply of current to the coil 4 but the movable iron core 12 is held by the holding coil 5. |
