Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Automatic circuit-interrupting devices
Patent
1998-12-14
2000-10-31
Donovan, Lincoln
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Automatic circuit-interrupting devices
335142, 335195, 218 22, H01H 7500
Patent
active
061408948
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to electrical circuit breakers and, more particularly, to electrical circuit breakers including a flexible electrical connector connected to a moving contact piece having a contact face arranged to make or break contact with a contact face on a relatively fixed contact piece to make or break an associated electrical circuit the respective contact faces extending generally perpendicular to the direction of movement of the moving contact piece.
One of the main considerations in the design of any circuit breaker is to ensure that sufficient pressure is applied to the current carrying contact faces by contact loading springs, in order to avoid welding together of the contact faces during a fault condition in the associated circuit. When an overload fault current flows through the contact faces a large amount of heat is produced. Dependent upon the design and type of contacts used and particularly with butt type contacts employed in vacuum interrupters there is usually a "blow-open" force involved. This is the electromagnetic force created by the fault current which tends to act to urge apart the contact faces, reducing the contact pressure, which increases the resistance and leads to further heating or even initial contact face separation and arcing. This heating or arcing can cause welding together of the contact faces. If welding occurs the circuit breaker opening mechanism will experience difficulty in separating the contact faces after the passage of a fault current and even may fail to interrupt the fault current.
SUMMARY OF THE INVENTION
According to one aspect, the present invention provides an electrical circuit breaker including a moveable contact piece connected to an actuating means and provided with a contact face arranged to make contact with a contact face of a second contact piece by movement of the moveable contact piece generally in a first direction, the circuit breaker further including an electrical connector for conveying current to the moveable contact piece, said electrical connector including at least two adjacent limbs adapted to convey said current in substantially opposing directions so as to generate an electromagnetic force repelling said adjacent limbs from one another which force is used to assist in maintaining the contact faces in abutment.
According to another aspect, the present invention provides an electrical circuit breaker including a moveable contact piece connected to an actuating means and provided with a contact face arranged to make or break contact with a contact face provided on a substantially fixed contact piece to make or break an associated electrical circuit, the respective contact faces extending perpendicular, or substantially perpendicular, to the direction of movement of the moveable contact piece wherein a flexible electrical connection extending from a fixed conductor to the moveable contact piece is formed as a sinuous strip having planar limbs connected one to another by a return bend with the planar limbs extending substantially perpendicular to the direction of movement of the moveable contact piece to generate electro-magnetically a force acting to repel one planar limb from an adjoining planar limb in the direction of movement of the moveable contact piece upon an electric current flowing through the flexible electric connection, the force being arranged to act between the moveable contact piece and the actuating means in a direction urging the contact faces into abutment.
Preferably, the flexible electrical connection is formed as a sinuous strip having at least three planar limbs connected by return bends. The outermost planar limbs may be of rigid construction whilst the intermediate limb or limbs and return bends are of resilient construction.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is a side elevational view, partially in diagramatic or schematic form showing essential workings of the electrical circuit breaker of the invention; and
FIG. 2 depicts an alternative embodime
REFERENCES:
patent: 3366900 (1968-01-01), Barkan
patent: 3550049 (1970-12-01), Blanc-Tailleur
patent: 3582587 (1971-06-01), Barkan
patent: 3614353 (1971-10-01), Yoshio
patent: 4025886 (1977-05-01), Barkan et al.
patent: 4032870 (1977-06-01), Oppel et al.
patent: 4153827 (1979-05-01), Mircovich et al.
patent: 4656444 (1987-04-01), McKee et al.
Donovan Lincoln
FKI PLC
LandOfFree
Electrical circuit breakers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrical circuit breakers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical circuit breakers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2056762