| 摘要 |
PROBLEM TO BE SOLVED: To prevent insulation degradation from occurring, when a movable contact is connected to and disconnected from a fixed contact, in response to the rotating operation of an operation knob by connecting and disconnecting it without trailing conductive grease. SOLUTION: When a contact piece 22b of a movable contact 22 is connected to and disconnected from a fixed contact 18, in response to the rotating operation of an operation knob, a projection 25 of a rotor 21 is guided by a waved slot 12, so that the movable contact 22 moves to the opposite side to an insulator 16 side to separate from the insulator 16, thereafter moves to the insulator 16 side and hence abuts on the insulator 16. Thereby, conductive grease containing carbide produced by the generation of arc discharge, when the movable contact 22 is connected to and disconnected from the fixed contact 18, is prevented from being trailed on the surface part of the insulator 16, so that the insulation performance between the moving positions of the movable contact 22 can be secured properly.
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