An improved circuit-breaker for alternating currents

摘要

942,916. Contact-members for switches; air-break switches. COMPAGNIE GENERALE D'ELECTRICITE. June 25, 1962 [July 13, 1961], No. 24274/62. Heading H2B. Two contact fingers 3, 4, pivoted at 16, 17, are connected by an articulation subjected to the action of springs such that the two fingers grip a double-faced stationary contact 1, 2, and the arrangement is such that the gripping pressure is reinforced by the electrodynamic forces due to the passage of current through the fingers between conductors 20 and 21. Spring 12 maintains contacts 1, 3, closed against the action of spring 5 which in turn maintains contacts 3, 4, closed. Finger 4 has an extension 32 carrying an auxiliary contact 8 maintained in contact with a spark-arresting or arc-rupturing finger 19 by springs 5 and 9 against the electrodynamic repulsive force between the parts 19 and 32. When a latch 22 is released, spring 12 extends sufficiently for spring 5 to be able to open contacts 1, 3. Spring 5 then pushes a lever 7 until it engages a stop 6 whereupon finger 4 begins to move and contacts 2, 4 open. Spring 9 keeps the auxiliary contact 8 closed until an abutment 10 on the rod carrying the finger 19 hits a stop 11 and the contact breaks. With heavy currents the electrodynamic forces assist the opening movement of finger 4 once contacts 1, 3, have opened. The electrodynamic forces hold the contacts closed however until the instantaneous current value is low enough for the spring opening force to overcome the electrodynamic forces and open the contacts.