EP0938121A2 - Automatic circuit breaker particularly low voltage protective circuitbreaker - Google Patents

Abstract

a) die Schalttraverse (3) für die Kontaktbrücken (4) besteht aus einem Duroplast-Werkstoff;

b) die Einschaltgeschwindigkeit der Kontakte (4, 5) zueinander beträgt unabhängig von der Betätigungsweise größer/gleich 3 m/s;

c) der Kontakthub ist größer/gleich 8 mm und überstreicht mindestens die Höhe der Löschkammereinsätze (11);

d) die Schaltergrundplatte (12) ist aus einem Thermoplastwerkstoff federelastisch ausgebildet und preßt die ebenfalls federnden Löschkammereinsätze (11) unter Federspannung mit ihren Lichtbogenleitblechen (10) gegen die starren Fortsätze (9) der festen Kontaktträger (7);

e) im Bereich des vorgesehenen Lichtbogenaustritts aus den Lichtbogenkammern ist die Wandung mit labyrinthartig gestalteten Auslaßschlitzen (14) für das Lichtbogenplasma versehen.

The invention relates to a circuit breaker, in particular low-voltage circuit breaker, with an insulating housing, a switch lock, U-shaped connecting rails with fixed contacts, which face movable contact bridges mounted in a switching crossbar and can be brought into contact with and released from them, and arc guiding and Arc quenching chambers with quenching plates for each switching pole. It is characterized by the combination of the following features:

a) the switching crossmember (3) for the contact bridges (4) consists of a thermoset material;

b) the switch-on speed of the contacts (4, 5) relative to one another is greater than or equal to 3 m / s;

c) the contact stroke is greater than / equal to 8 mm and covers at least the height of the arcing chamber inserts (11);

d) the switch base plate (12) is made of a thermoplastic material and resiliently presses the likewise resilient quenching chamber inserts (11) under spring tension with their arc guide plates (10) against the rigid extensions (9) of the fixed contact carriers (7);

e) in the area of the intended arc exit from the arc chambers, the wall is provided with labyrinth-like outlet slots (14) for the arc plasma.

Description

The invention relates to a circuit breaker, in particular a low-voltage circuit breaker, with a multi-part Insulated housing, a switch lock, loop-shaped Connection rails with fixed contacts, which movable contact bridges face each other and with them can be brought into contact and released and arc guiding and quenching plates having arc quenching chambers for each switching pole.

Low voltage circuit breakers are usually switches with current heat releases as well as with quick releases, who work on a key switch and serve primarily that Overload and short circuit protection. Own as a lock switch they shutdown properties. In addition, they can be operate manually using an ON / OFF control element and switch remotely if necessary.

Said switches are used in large numbers as motor protection switches, by limiting their tripping characteristic to the Operating conditions of an engine to be protected is adapted in an electrical system. Protection relates both on the permissible long-term heating of a Motors as well as its protection against short circuit.

In addition, low-voltage circuit breakers are found as so-called Circuit breaker application. Protect as such an electrical system against impermissible operating conditions. You can use currents under operating conditions in the Switch on, lead and switch off circuit. Furthermore they must also be under specified exceptional conditions - like short circuit - switch on during a be able to carry electricity and switch off for a specified time.

The electrical requirements for a circuit breaker are regularly much higher than on a motor protection switch. So a circuit breaker must be twice in a row switch to a pending short circuit in the system can safely switch off the short circuits and then still be able to run the normal operating current respectively. For reasons of cost, therefore, for both Use cases built special equipment, and that though the principle of operation of both circuit breakers is the same is.

The invention has for its object a solution find, after which a motor protection switch structurally identical can be used as a circuit breaker for a system can, the constructive - and material costs close to the effort of a conventional motor protection switch to orient.

The object is achieved by the in claim 1 specified features solved. Advantageous configurations are specified in the accompanying subclaims.

Fig. 1 den Schaltteil eines Schalters im Schnitt

Fig. 2 eine Schaltkammer in der Draufsicht.

The invention will be explained in more detail using an exemplary embodiment and the associated drawing. In the drawing shows

Fig. 1 shows the switching part of a switch in section

Fig. 2 shows a switching chamber in plan view.

The automatic switch in the manner of a conventional motor protection switch consists essentially of an upper part 1 with a switch lock, not shown, which can be switched on via a switch 2 and by means of a switch, not shown, and are triggered by electricity and magnetic triggers can.

The on and off movements are on a switching crossbar 3 transmit the spring-loaded movable Contact bridges 4 accommodates. The moment activation ensures a switch-on speed of> = 3m / s, so that no dangerous arc can develop. The switch crossbar 3 is made of a thermoset material, the one Melting of the contact bridges 4 prevented and temperature resistance up to 220 ° C.

When switching on, the movable contact bridges 4 moves against the fixed contacts 5, the contact pressure springs 6 ensure sufficient contact pressure. Of the Switching stroke is approx. 8 mm in the example. The fixed contacts 5 sit on contact carriers 7, which are in a wide loop are led to the outer connections 8. The loop guide enables in connection with the movable Contact bridges 4 at the electrodynamic contact separation short-circuit-like currents.

Opposite the loop end is on the other side of the fixed contact piece 5, a small extension 9 is formed. Against this extension 9, the baffle 10 of the Extinguishing chamber insert 11 by the force of the elastic Base plate 12 and the elastic quench chamber inserts 11 pressed. This makes it structurally smoother and more conductive Transition from fixed contact 5 to guide plate 10 and thus created for the extinguishing chamber insert 11. The contact pressure the base plate 12 and the elastic quench chamber inserts 11 prevents the baffle 10 from moving from the fixed contact carrier 7 takes off when forming the switching arc and so that the galvanic connection is separated, which is a uncontrolled training that destroys the control chamber of an arc.

The switching arc runs into the quenching chamber insert 11 one, divides itself into sections, runs through the whole Chamber, is cooled and ultimately safely extinguished. The contact stroke of the movable contacts 5 is at least as large as the height of the quench chamber insert 11, with what it is ensured that really all the quenching plates and that Baffle plate 10 used for arcing and quenching become.

The arc plasma creates in the closed Switch lower part 13 a sudden excess pressure, the is degraded in a controlled manner by means of the outlet slots 14. If the arc is strong, the arc plasma could after leaving the outlet slots 14, the individual Bridge current phases due to ionization of the outside air and cause dangerous short circuits, which is why the outlet slots 14 additionally formed like a labyrinth are.

The insulating webs 15, which the individual baffle plates of Hold extinguishing chamber insert 10 are such that the quenching plates are very precise and mechanically fixed to each other stand and are not driven apart by the arc. In addition, their stiffness is higher than that of elastic Base plate 12 to the pressing force of the base plate 12 transfer to the fixed contact carrier 7 without loss.

Provided with the measures known in part as such a conventional motor protection switch is surprising overall Circuit breaker parameters, which is a completely new Quality means. So a motor protection switch could Size 25A brought to the level of a circuit breaker become.

One area of application for such a circuit breaker is Example of use in conjunction with a contactor for so-called power outflows.

Reference numerals

Top

1

Power button

2nd

Crossbar

3rd

Contact bridges

4th

Fixed contact

5

Contact pressure spring

6

Contact carrier

7

Connection

8th

Continuation

9

Baffle

10th

Extinguishing chamber insert

11

Base plate

12th

Switch base

13

Outlet slots

14

Insulating bars

15

Claims (3)

Automatic switches, in particular low-voltage circuit breakers, with an insulating housing, a switch lock, U-shaped connecting rails with fixed contacts, which are opposed by movable contact bridges mounted in a switch crossbar and can be brought into contact with and released from them, and arc-quenching chambers having arc guiding and quenching plates for each switching pole , characterized by the combination of the following features: a) the switching crossmember (3) for the contact bridges (4) consists of a thermoset material; b) the switch-on speed of the contacts (4, 5) relative to one another is greater than or equal to 3 m / s; c) the contact stroke is greater than / equal to 8 mm and covers at least the height of the arcing chamber inserts (11); d) the switch base plate (12) is made of a thermoplastic material and resiliently presses the likewise resilient quenching chamber inserts (11) under spring tension with their arc guide plates (10) against the rigid extensions (9) of the fixed contact carriers (7); e) in the area of the intended arc exit from the arc chambers, the wall is provided with labyrinth-like outlet slots (14) for the arc plasma. Automatic switch according to claim 1, characterized in that the insulating webs (15) for the quenching plates of the quenching chamber inserts (11) are substantially stiff and the Secure the fire-fighting plates mechanically. Automatic switch according to claim 1, characterized by the use in a power outlet.

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