US 4,301,341 AGranted

Electrical switchgear

AssigneeSouth Wales Switchgear Limited

InventorJohn Parry

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Abstract

On opening of a circuit breaker, an end portion of a pivotable contact arm disengages from fixed contacts such that an arc is drawn therebetween radially across the pole face of a field coil, the end portion of the contact arm moving transversely to the field coil axis. The arc then transfers from the fixed contacts to a tubular electrode thereby bringing the field coil into circuit so that a magnetic field is generated which causes the arc to rotate and become extinguished. In the fully-open position of the circuit breaker, the end portion of the contact arm lies along the field coil axis. The whole assembly is disposed in a housing which contains the highly insulating gas sulphur hexafluoride. A single field coil and electrode can be shared between two such constructions. In addition, the initial arc can be drawn directly between the contact arm and the tubular electrode, rather than being transferred to the electrode from the fixed contacts.

Claims24

Dependent claims

Electrical switchgear comprising:

(a) a housing containing an electrically insulating fluid;
(b) an electrically conductive arcing electrode disposed in said housing;
(c) a switch disposed in said housing and 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 formed between said first contact means and said arcing electrode, and;
(d) a field coil having an axis and electrically connected in series with said arcing electrode, an arcing current flowing through said field coil when said electrical arc discharge is formed between said first contact means and said arcing electrode and producing a magnetic field which causes said electrical arc discharge to rotate between said first contact means and said arcing electrode and become extinguished;
(e) said first contact means including an electrically conductive contact arm which is pivotable about a pivot axis transverse to said field coil axis, said contact arm having an end portion which moves transversely to and inwardly of said field coil axis on movement of said first and second contact means away from said closed position and towards said open position.

2 more elements

Dependencies are inferred from the claim text.