US 4,301,340 AGranted

Electrical switchgear

AssigneeSouth Wales Switchgear Limited

InventorJohn Parry

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Abstract

A pair of switches are disposed adjacent one another in a housing which contains the highly insulating gas sulphur hexafluoride. In a closed position of each switch, a pivotable contact arm engages fixed contact fingers to permit the flow of load current therethrough. On opening of each switch, the contact arm pivots away from the fingers so that an arc is drawn therebetween, the arc subsequently being transferred from the fingers to a tubular electrode. The arc current then flows through a field coil connected in series with the electrode, such that a magnetic field is generated which causes the arc to rotate and become extinguished. The electrode and field coil are common to both switches, the contact arms of the latter being disposed respectively at opposite ends of the coil and being isolated from each other by a transverse insulating member disposed centrally in the electrode. The field coil is spirally wound so as to be symmetrical about a transverse plane through its centre, and therefore provides the same operating characteristics for each of the two switches.

Claims7

Dependent claims

Electrical switchgear comprising:

(a) a housing containing an electrically insulating fluid;
(b) a pair of switches disposed in said housing, each said switch including first contact means and second contact means which are relatively movable between a closed position in which said first and second contact means are mutually engaged and an open position in which said first and second contact means are mutually separated, movement of said first and second contact means out of said closed position and towards said open position causing an electrical arc discharge to be drawn therebetween;
(c) electrically conductive arcing electrode means disposed in said housing and to which said electrical arc discharge is transferred from said second contact means upon further movement of said first and second contact means of each said switch towards said open position;
and
(d) a field coil which is common to both said switches and which is electrically connected to said arcing electrode means, an arcing current flowing through said field coil when said electrical arc discharge is transferred to said arcing electrode means from either of said switches and producing a magnetic field which causes said electrical arc discharge to rotate between said first contact means and said arcing electrode means and to become extinguished.

2 more elements

Dependencies are inferred from the claim text.