US 4,714,907 A · Miniature electrical circuit breaker with multiple moving contacts and thermomagnetic trip release

Abstract

The invention relates to a multiple moving contact assembly for a miniature circuit breaker with high ratings and a thermomagnetic trip release. The moving contact part of the circuit breaker includes two independent contact arms connected in parallel and mounted on a transverse spindle of the cradle. The arms are connected to a magnetic circuit of the electromagnetic trip release by two braids situated in symmetrical lateral areas. The contact parts bear on a single stationary contact pad so as to create two contact points enabling the temperature rise to be reduced. The electromagnetic top release has a coil including a tail arranged as an adjustable support device of a bimetallic strip, through whose foot the current flows thicknesswise. The tail is provided with a hinge between the junction point of the bimetallic strip and the coil, so as to allow relative movement of part of the tail due to the action of the thermal tripping threshold setting screw, the other part connected to the coil remaining appreciably station.

Claims13

Dependent claims

A low voltage miniature electric circuit breaker with insulated casing equipped with a mechanism controlled by a thermomagnetic trip release, comprising:

a first thermal trip release having a bimetallic strip cooperating with said mechanism when an overload current exceeds a thermal tripping threshold;
a second electromagnetic trip release for protection against short-circuit current, comprising a control coil electromagnet, made up by helical winding of a deformable conductor having a preset rigidity;
an end turn of said coil being extended with the same conductor by a tail cooperating with an adjustment device for the thermal tripping threshold of the first thermal trip release;
said tail being arranged as an adjustable support part of the bimetallic strip which has a foot inserted by soldering between said tail and an adjacent elecrical connection means electrically connected to a contact pad, to cause the current to flow thicknesswise through the foot of the bimetallic strip;
and
a hinge located along said tail between the foot of the bimetallic strip and the end turn of the coil, to allow relative movement of one part of said tail due to the action of the thermal tripping threshold adjusting device, the other part of the tail connected to the end turn of the coil remaining appreciably stationary.

3 more elements

A low voltage miniature electric circuit breaker with a parallelipipedic molded insulated casing, each pole of the circuit breaker comprising:

an opening and closing mechanism occupying almost the whole width of the casing and controlled either by a thermomagnetic trip release ensuring automatic tripping in the event of a short-circuit or overload, or by a manual control handle, the trip release comprising a bimetallic strip and an electro-magnet with a coil and sliding plunger core;
a pair of pole connection terminals;
a stationary contact assembly electrically connected to one of the terminals;
a moving contact assembly mechanically coupled to the mechanism for actuation between an open position and a closed position and electrically connected to the other terminal via the coil;
an extractor rod securely fixed to the moving core of the electromagnet and shifting the moving contact assembly at high speed to the opening position when tripping occurs on a short-circuit;
an arc chute formed by stacking of metal deionization plates, the trip release electromagnet being located between the arc chute and the mechanism depth-wise in the casing;
a pair of arc guiding electrodes or horns on which the arc strikes after separation of the contacts;
a common transverse spindle articulated on a cradle of said mechanism;
a plurality of identical independent contact arms of said moving contact assembly being mounted at regular intervals on said spindle within said pole, each moving contact arm comprising a contact part and a braid for electrical connection with the coil;
said assembly having a symmetrical multiple structure with several branched elementary circuits, each having a fraction of the pole rated current flowing through it resulting in the contact points with the stationary contact assembly being multiplied;
and
the extractor of the electromagnet extending in the mid-plane of the casing to act simultaneously on all the independent contact arms when a shortcircuit occurs, with the formation of several parallel elementary arcs at the beginning of opening travel of the contacts.

9 more elements

Dependencies are inferred from the claim text.

Miniature electrical circuit breaker with multiple moving contacts and thermomagnetic trip release

Life of this patent

Miniature electrical circuit breaker with multiple moving contacts and thermomagnetic trip release

Life of this patent

Abstract

Claims13