Unipolar cutoff unit useful in cutoff device for circuit-breaker, comprises rotating contact bridge, pair of fixed contacts connected with bridge, rotating rod having transverse opening, sealing shields, and arc extinction chambers

摘要

The unipolar cutoff unit comprises a rotating contact bridge (22), pair of fixed contacts (41, 51) connected with the contact bridge and to a conductor (4, 5) of current lead, a rotating rod (26) having a transverse opening of housing (21) with clearance from the contact bridge, which extends out from the bar, sealing shields respectively placed between the radial faces of the rotating bar and sides to ensure a seal between inside and outside the phase unit, and two arc extinction chambers opening on a volume of opening of the contact bridge. The unipolar cutoff unit comprises a rotating contact bridge (22), pair of fixed contacts (41, 51) connected with the contact bridge and to a conductor (4, 5) of current lead, a rotating rod (26) having a transverse opening of housing (21) with clearance from the contact bridge, which extends out from the bar, sealing shields respectively placed between the radial faces of the rotating bar and sides to ensure a seal between inside and outside the phase unit, and two arc extinction chambers opening on a volume of opening of the contact bridge. The rotating bar is interposed between two sides of the phase unit, and comprises parallel side faces and two channels of direct link between the transverse opening of housing and a radial face so that the cut gas flows directly through the channel towards the sealing shield to push against the side faces to ensure the sealing. The opening channel comprises a longitudinal axis parallel to a longitudinal axis of the rotating bar so that the cutoff gas exerts a force aligned with the longitudinal axis of the bar and spread evenly over the sealing shields. The sealing shields comprise side flanges partially covering the longitudinal surface of the rotary bar. The side flanges are partially close to the transverse opening of the housing of the rotary bar. The sealing shields further comprise a hole for the passage of linking bar for mechanically fixing the rotating bars, where the linking bars are controlled by a mechanism common to all unipolar units. Each cutoff chamber is connected to an exhaust channel of the cutoff gas. The exhaust channels are opened on upstream face of the casing of the cutoff phase, which is positioned opposite to another downstream face intended to be placed contacting with a triggering unit. The exhaust channels of cutoff gas respectively of first and second cutoff chamber have different lengths, where the cutoff gas flowing in an exhaust channel is intended to draw the gas flowing through a second exhaust channel by Venturi effect. The gas exhaust channel of arc cutoff chamber crosses a decompression chamber comprising an internal wall covered by a metal sheet.