FR2722609A1 - ELECTRIC CIRCUIT BREAKER WITH ELECTROMAGNETIC ACTUATOR FOR HIGH CALIBERS - Google Patents

Abstract

The circuit breaker is fitted with an electromagnetic actuator (AE), comprising a magnetic circuit (7) in the form of an `H'. The circuit includes a first air gap (17) in which a mobile contact arm (5) is suspended and a second air gap (19) associated with a pivoting paddle (8). A hammer (9) is connected to the paddle (8) to reinforce the opening action of the contact arm (5). The hammer (9) is formed by an extended piece situated between the magnetic circuit (9) and the first compartment (30). This cooperates with the support (26) of the contact arm to block the passage between the first and second compartments after attraction of the paddle, and to free the passage after the return of the paddle to its separated position.

Description

ELECTRIC CIRCUIT BREAKER WITH ELECTROMAGNETIC ACTUATOR FOR

HIGH CALIBER

  The invention relates to an electrical circuit breaker with molded insulating housing comprising a first compartment for housing the control mechanism, and a second compartment containing an electromagnetic actuator, and separable contacts associated with a breaking chamber, said actuator having a circuit magnetic, and comprising: - a core on which an excitation coil is mounted, Io - a first air gap in which the movable contact arm extends to occupy a rest position in the closed state of the contacts, and a active position of contact separation when the current intensity exceeds a predetermined threshold, - a pivoting pallet cooperating with the polar faces of the magnetic circuit to form a second air gap located opposite the first air gap, - and a striker associated with the pallet to act on the contact arm in the direction of

  the opening after magnetic attraction of the pallet against the polar faces.

  Use of an electromagnetic actuator in a circuit breaker to cause

  rapid separation of the contacts makes it possible to obtain very high breaking powers.

  The extinction of the arc in the breaking chamber nevertheless generates ionized gases capable of producing phenomena of external manifestations. These phenomena are particularly undesirable on the front side, due to the escape of gas

  ionized by the orifice allowing the movement of the lever.

  The object of the invention is to provide an electrical circuit breaker for high

  performance, insensitive to any phenomenon of external manifestations.

  The circuit breaker according to the invention is characterized in that the striker is formed by an elongated piece located between the magnetic circuit and the first compartment, and cooperating with the means for supporting the contact arm to close the passage between the first and second compartments after attraction of the pallet, and to free said passage after the

  recall the pallet to the discarded position.

  According to a preferred embodiment of the invention, the axis of connection of the striker on the pallet is disposed in an intermediate zone between the axis of articulation of the pallet, and the second air gap. The striker constitutes a screen which adapts to the internal part of the housing. The passage between these two compartments is advantageously located above the

  first air gap opposite the fixed contact.

  According to a characteristic of the invention, the means for supporting the contact arm comprise drive stops cooperating with the mechanism, and a bearing face cooperating with the free end of the striker to delimit said passage

  Other advantages and characteristics will emerge more clearly from the description which follows.

  follow of an embodiment of the invention, given by way of nonlimiting example, and shown in the accompanying drawings, in which: FIG. 1 is a diagrammatic elevation view of the circuit breaker equipped with the actuator according to the invention .

  FIG. 2 represents a perspective view of the actuator of FIG. 1.

  Figure 3 is a sectional view through the median plane of the actuator of Figure 2, the pallet

  and the striker being in the inactive position.

  Figure 4 shows a plan view of Figure 3.

  Figure 5 is an identical view to Figure 3, in the active position of the pallet and the striker.

  Figure 6 is a plan view of Figure 5.

  With reference to FIG. 1, a circuit breaker 1 comprises a housing 2 containing a fixed contact 3, a movable contact 4 mounted at the end of a movable contact arm 5, a breaking chamber 6 and various elements of electrical connections ( not shown) used to connect the fixed and movable contact to terminals (not shown). The circuit breaker additionally includes an electromagnetic actuator AE which, in the event of a fault, triggers the

  circuit breaker, and rapid separation of fixed and mobile contacts 3, 4.

  The electromagnetic actuator AE comprises a yoke 7 made of magnetic material, a

  swivel pallet 8, and a striker 9.

  In FIG. 2, the H-shaped cylinder head or magnetic circuit 7 has a cylindrical core 10 surrounded by a coil 34, and two sides 11, 12 arranged parallel to each other, and extending perpendicular to the axis of the core 10 The side 11 has a first end 13 directed towards the pallet 8 and a second opposite end 14. The other

3 2722609

  sidewall 12 comprises a third end (not shown) directed towards the pallet 8 and a fourth opposite end 16. The first end 13 and the third end form polar planar faces cooperating with the flat face 18 of the pallet 8. The second and fourth ends 14, 16 form flat faces arranged opposite one another to delimit a first air gap 17. When the electromagnetic actuator AE is at rest, the pallet 8 is located at a certain distance from the face 18 of the cylinder head 7 by forming a second air gap 19. The pivoting pallet 8 is mounted on a hinge pin 21 and the movable contact arm 5 is also pivotally mounted by means of another hinge pin 22. The fixed contact 3 is located at the base of the air gap 17, and at least part of the movable contact arm 5 extends through the air gap 17. The striker 9 is in the form of an elongated part substantially rectangular, one end of which is articulated on a connecting pin 23 arranged on the pallet 8, and the other free end 24 of which is located near the

  movable contact arm 5, and on the side opposite to the fixed contact 3.

  The width of the striker roughly corresponds to the width of the housing.

  Referring to Figures 3 to 6, the contact arm 5 is carried by support means 26 arranged opposite the movable contact 4, and having drive stops cooperating with

  the mechanism (not shown) for closing and separating the contacts 3, 4.

  The support means 26 additionally comprise a support face 36 cooperating with

  the free end 24 of the striker 9.

  The connecting axis 23 of the striker 9 on the pallet 8 is located in an intermediate zone between the articulation axis 21 and the second air gap 19. The free end 24 of the striker 9 is separated from the bearing face 36 by a passage 28 in the form of a slit whose thickness is

  variable depending on the magnetization state of the electromagnetic actuator AE.

  In the closed position of the contacts 3, 4 (FIGS. 3 and 4), the magnetic flux in the second air gap 19 following the passage of the nominal current through the coil of the actuator AE, is insufficient to attract the pallet 8 against the surfaces polar 13 of the cylinder head 7. The pallet 8 is held in the separated position under the action of its return spring, and the striker 9 also remains stationary in the inactive position. The slot 28 between the striker 9 and the support means 26 of the arm 5 is maximum, and allows the communication of the area

  contacts with the upper compartment 30 for housing the mechanism 31.

4 2722609

  In the presence of a short-circuit current, the increase in magnetic flux in the cylinder head 7 generates significant electromagnetic forces in the first air gap 17, urging the contact arm 5 towards the open position (Figures 5 and 6) . The pivoting pallet 8 is attracted simultaneously against the pole surfaces 13 of the second air gap 19, and drives the striker 9 in translation in the same direction. The coming into engagement of the end 28 against the support means 26 accelerates the pivoting of the contact arm 5 towards the open position, and at the same time closes the slot 28. The ionized gases generated by the arc during the separation of the contacts 3, 4 cannot escape towards the upper compartment 30, and remain confined in the lower compartment 32 of the housing of the breaking chamber 6. The striker 9 in addition to its acceleration function of the contact arm 5, thus acts as a separation screen between the two compartments, and the slot 28 remains closed in the attracted position of the pallet 8, that is to say as long as the current in the coil exceeds a predetermined value. Closing the slot 28 during the arc extinction phase prevents any gas backflow towards the upper compartment 30, and in particular towards the orifice for passage of the lever, so as to avoid any phenomenon of external manifestations on the front face of the

housing 2.

s 2722609

Claims (4)

  1.Electrical circuit breaker with molded insulating housing (2) comprising a first compartment (30) for housing the control mechanism (31), and a second compartment (32) containing an electromagnetic actuator (AE), and separable contacts (3, 4) associated with a breaking chamber (6), said actuator having a magnetic circuit (7), and comprising: - a core (10) on which is mounted an excitation coil (34), - a first air gap (17 ) in which extends the movable contact arm (5) to occupy a rest position in the closed state of the contacts (3, 4), and an active position of contact separation when the current intensity exceeds a predetermined threshold, - a pivoting pallet (8) cooperating with pole faces (13) of the magnetic circuit (7) to form a second air gap (19) located opposite the first air gap (17), - and a striker (9 ) associated with the pallet (8) to act on the contact arm (5) in the direction of or verture after magnetic attraction of the pallet (8) against the pole faces, characterized in that the striker (9) is formed by an elongated piece located between the magnetic circuit (7) and the first compartment (30), and cooperating with the support means (26) of the contact arm (5) for closing the passage (28) between the first and second compartments (30, 32) after attraction of the pallet (8), and for releasing said passage after   the return of the pallet (8) to the separated position.   2. Circuit breaker according to claim 1, characterized in that the connecting pin (23) of the striker (9) on the pallet (8) is arranged in an intermediate zone between the axis   hinge (21) of the pallet, and the second air gap (19).   3. Circuit breaker according to claim 2, characterized in that the striker (9) constitutes a screen which adapts to the internal part of the housing (2), and that the passage (28) is located above   the first air gap (17) opposite the fixed contact (3).   4. Circuit breaker according to one of claims 1 to 3, characterized in that the means of   support (26) of the contact arm (5) have drive stops cooperating with the mechanism (31), and a bearing face (36) cooperating with the free end (24) of the striker to delimit said passage (28).