(57) In an ultrarapid-release current-limiter electrical switch comprising at least a
support with a stationary contact, at least a movable contact borne by an arm rotatably
mounted in a movable unit and submitted to the action by a spring reacting against
the movable unit, and a control mechanism with a control lever, an oscillatable lever
kept stopped by a release device, a toggle lever system between said movable unit
and said oscillatable lever and an extension spring acting between said control lever
and the hinge of said toggle lever system, said support of the stationary contact
and said movable contact bearing arm defining, under contact closure conditions, two
portions parallel and close to each other in the current path, wherein currents of
opposite sign flow, which are suitable to produce, in case of strong current intensities
due to short-circuits, repulsive electrodynamic forces; between said movable contact
bearing arm and said release device for the oscillatable lever of the control mechanism
mechanical means are interposed suitable to cause, on a displacement of said arm by
eletrodynamic repulsion, directly the release of said oscillatable lever.
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