ELECTRICAL DIFFERENTIAL CIRCUIT BREAKER INCLUDING A TEST DEVICE FOR THE DIFFERENTIAL FUNCTION

Description

TECHNICAL FIELD

[0001] The present invention relates to a differential electrical cut-off device housed in an insulating case containing a first cut-off compartment comprising at least one electrical circuit having a fixed contact and a movable contact, a first mechanism for controlling the closing and opening of the aforementioned contacts, manually controlled by a lever and automatically controlled, a second compartment called differential protection compartment comprising means for detecting a differential fault in the circuit to be protected, means for triggering a control mechanism called the second capable of causing the opening of this mechanism when such a fault occurs, means for transmitting the tripping order to the control mechanism called the first, and means for electrically testing the differential function intended to cause the tripping of the second mechanism when they are activated, which test means are actuated by test control means. STATE OF PRIOR ART

[0002] In the field of differential electrical cut-off devices, testing the differential function is mandatory to check its operation approximately every month.

[0003] In known devices, this verification of the operation of the differential function causes the power contacts to open.

[0004] However, in some applications, cutting off the power contacts is not acceptable during testing, for reasons of service continuity, safety and cost, because this procedure results in the shutdown of an application or process, then a restart.

[0005] Document DE 102004045937 describes a differential switching device comprising a blocking device, itself controlled by a safety device, so that the blocking device is neutralized when a differential current fault occurs.

[0006] Document EP-0 231 732-A1 describes a differential cut-off device according to the preamble of claim 1.

[0007] The present invention solves these problems and provides a differential electrical cut-off device of simple design, allowing the electrical test of the differential to be carried out without causing an interruption in the continuity of service. STATEMENT OF THE INVENTION

[0008] The present invention relates to a differential electrical cut-off device according to claim 1.

[0009] According to a particular characteristic, this device comprises so-called primary means, for immobilizing this return during the test at least until the differential mechanism is closed.

[0010] According to another characteristic, this device includes so-called second means for closing the differential mechanism, the test circuit being in the open position.

[0011] According to another characteristic, these means for controlling the differential test comprise a button called a test button capable of being actuated by a user and mounted in translation relative to the housing of the device between two positions corresponding respectively to an open position and a closed position of said switch called the second.

[0012] According to a particular embodiment, the means for immobilizing the return are carried by the differential test control means and actuated when the aforementioned control means are activated.

[0013] According to another characteristic, this device comprises means for preventing the so-called first switch of the test circuit from re-closing during the re-closing of the so-called second mechanism after carrying out a differential test.

[0014] According to another characteristic, these means for preventing the so-called first switch from closing again comprise means for returning the so-called first switch to the open position, and in that the differential or second mechanism comprises a plate, this plate comprising a part capable of being driven by the test control means when they are activated, so as to close the so-called first switch, and to retract when the differential mechanism opens, so as to allow the so-called first switch to be returned to the open position, and to allow the differential mechanism to close again, the so-called first switch being held in the open position.

[0015] According to another characteristic, these means for preventing the so-called first switch from closing comprise a so-called first pawl mounted to rotate relative to the test button and a so-called second pawl secured to the plate of the second mechanism, the first pawl being returned above the second pawl by a spring at the start of actuation of the test button then, during actuation of the test button, the pawl driving the plate of the second mechanism in the direction of opening of the so-called second mechanism, the second pawl being able to retract to pass above the first pawl at the moment of this opening of the second mechanism, this retraction allowing the so-called first switch to open and being maintained during the reclosing of the so-called second mechanism so as not to close the so-called first switch, this first pawl being able to retract when the test button is released in order to pass above the second pawl,this in order to make it possible to carry out a new test.

[0016] According to another embodiment, the means for immobilizing the return are carried by blocking means actuable by the user and independent of the differential test control means.

[0017] According to a particular characteristic, the so-called first switch is controlled by the differential mechanism and these so-called second means comprise the following sequencing for carrying out the test by the user: the blocking means are brought into the active blocking position, then the test control means are activated, which causes the second switch to close, the first switch being returned to the closed position, after which the so-called second mechanism opens under the effect of the closing of the test circuit, which causes the opening of the first switch initially closed, then the test control means are deactivated, which causes the second switch to open and the so-called second mechanism to close, which causes the first switch to close.

[0018] According to another characteristic, the locking means comprise a tool external to the device or a pusher integrated into the device.

[0019] According to another characteristic, the two aforementioned switches are formed respectively by two free ends of a spring blade cooperating respectively with two fixed points of the test circuit.

[0020] According to another characteristic, the so-called second ratchet comprises a first part shaped like a fork capable of cooperating with the end part of the spring blade belonging to the first switch and a second portion capable of sliding on the first ratchet when the so-called second mechanism is closed.

[0021] According to another feature, it is a single-pole and neutral differential circuit breaker.

[0022] According to another characteristic, the first and second mechanisms each comprise a plate, the return, the plate of the first mechanism and the plate of the second mechanism are mounted around the same axis, and the plate of the differential mechanism comprises a protuberance capable of cooperating with the aforementioned return.

[0023] But other advantages and characteristics of the invention will appear better in the detailed description which follows and refers to the appended drawings given solely by way of example and in which: THE figures 1 to 17 relate to a first embodiment of the invention, while the figures 18 to 30 relate to a second embodiment of the invention; The Figure 1 is a perspective view of a differential circuit breaker according to the first embodiment of the invention, and comprising a cutaway, The Figure 2 is a perspective view of the same device, parts of its casing having been removed so as to reveal its interior part, The Figure 3 is a partial perspective view, illustrating the part of the mechanism concerned by the invention, The Figure 4 is an exploded view of the previous figure, The Figure 5 is a view similar to the Figure 3 , view from the other side of the device, The Figures 6 and 7are partial plan views illustrating the interior part of the device, respectively seen from two opposite sides of the device and in the open position of the circuit breaker, The figures 8 and 9 are views identical to the previous ones, the device being in the closed position, The figures 10 to 17 are partial plan or perspective views illustrating the mechanism during the performance of the electrical test, The figure 18 is an exploded view of the part of the mechanism concerned by a second embodiment of the invention, The figures 19 And 20 illustrate this same mechanism according to two different orientations, The figures 21 and 22 are partial plan views, illustrating the interior part of the device, respectively seen from two opposite sides of the device in its open position, The figures 23 And 24 are two partial views respectively in plan and in perspective, illustrating the mechanism of the circuit breaker in the closed position, and The figures 25 to 30are partial plan or perspective views, illustrating this same mechanism during the performance of the electrical test. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] On the Figure 1 , we see a device comprising a differential module 2 associated with a circuit breaker module 1, this device being of the single-pole and neutral type, but can also be of the two-pole, three-pole, three-pole and neutral type, etc.

[0025] In the following figures, only mechanism 3 of differential module 2 has been shown.

[0026] In a manner known per se, the circuit breaker module not shown comprises a phase circuit connected to a first pair of phase terminals.

[0027] The phase circuit comprises a movable contact electrically connected to the upstream terminal by a bimetallic trigger, and a fixed contact connected to an excitation coil of an electromagnetic trigger. A first arc extinguishing chamber is arranged between the electromagnetic trigger and the bottom of the housing, and comprises a pack of deionization sheets for the arc drawn between the contacts.

[0028] The neutral circuit has a fixed contact and a movable contact electrically connected to two terminals, upstream and downstream, and a second arc extinguishing chamber. The neutral circuit is located to the left of the phase circuit and does not have a magnetothermal trip unit.

[0029] The two moving contacts are actuated by a first mechanism not shown with manual control via a lever M, Figure 1, and automatically by the bimetal thermal release and the electromagnetic coil release.

[0030] The second module, called differential module 2, is located to the right of the first module 1, and contains a differential transformer having a secondary winding connected to a tripping relay cooperating with a second mechanism 3 with a reset handle N. This second mechanism 3 is coupled with the first mechanism of the circuit breaker by means of mechanical links allowing a tripping action of the circuit breaker when a differential tripping order is issued by the relay, and a continued action of resetting the second mechanism. This second mechanism may be of the type described in document FR-A-2.628.262 and comprises a rotating plate 5 connected to the corresponding handle N by a breakable mechanical link and a trip lever 8 capable of being actuated by the relay in the event of a fault in order to cause the mechanical link to break and the plate 5 to rotate.Thus, and in a manner known per se, when an insulation fault occurs in the electrical circuit to be protected in which the circuit breaker is placed, the differential detector causes the relay coil to be energized, which causes the differential control mechanism to trip, and the cascade tripping of the circuit breaker block mechanism via the mechanical connection.

[0031] The differential transformer consists of a magnetic core carrying a primary phase winding, a primary neutral winding, and the secondary measuring winding. An earth fault causes an imbalance between the primary currents flowing through the primary windings, and generates an induced voltage across the secondary winding to energize the tripping relay.

[0032] In a manner also known per se, this second mechanism 3 is equipped with an electrical testing device 11 of the differential mechanism, this device being housed in the second module 2, and having a push button 12 intended to be actuated by sliding between a raised rest position and a depressed working position. This test device 11 also comprises an electrical resistor 13 inserted in a test circuit connected between an interconnection lug of a connecting conductor 14 of the phase circuit, and the connecting conductor 15 of the primary neutral winding. The resistor 13 is connected in series with a protection switch 16, called the first, actuated by the mechanism called the second 3, and a test switch 17, called the second, controlled by the push button 12. The protection switch 16 is formed by an end portion 18a of a conductive elastic blade 18 bearing in the closed position on the aforementioned connecting conductor 14.The so-called test switch 17, or second, comprises a strand 18b of the conductive spring 18 intended to cooperate in the pressed position of the push button 12, with an end wire 19 of the resistor 13.

[0033] Thus, the two ends of the test circuit 11 are connected simultaneously downstream of the phase and neutral contacts.

[0034] In a manner known per se in the differential testing devices of the prior art, the circuiting of the resistor 13 occurs when the two switches 16, 17 are closed, that is to say in the armed state of the second mechanism 3, and in the pressed working position of the push button 12. This results in a test current in the resistor, which is detected by the differential transformer which causes the tripping of the second mechanism 3, then of the so-called first mechanism of the circuit breaker D. The pivoting of the rotating plate 5 of the differential mechanism 3 causes the automatic opening of the first protection switch 16, resulting in the interruption of the test current in the resistor 13, even if the push button 12 remains held in the pressed position.

[0035] According to the invention, this apparatus comprises means for carrying out this electrical test of the differential trip device by triggering its mechanism without triggering the mechanism of the circuit breaker D.

[0036] These means commonly comprise two embodiments described and illustrated in the figures 1 to 17 for the first realization, and on the figures 18 to 30for the second embodiment, a return 22 mounted to rotate around an axis Y fixed relative to the housing B of the device, said return 22 being able to be driven by the plate 5 of the differential mechanism 3, when a differential fault occurs, and to drive the plate of the circuit breaker D in order to trigger it by means of a needle 9 secured to said return 22. To do this, the plate 5 of the differential mechanism 3, the plate of the circuit breaker mechanism and the return 22 are mounted to rotate around the same axis Y, and the plate 5 of the differential mechanism 3 has a protuberance 23 extending parallel to the aforementioned axis of rotation Y and being able to cooperate with the return 22 to allow the plate of the circuit breaker D to be driven by the plate 5 of the differential mechanism 3 via the return 22.

[0037] These means also include so-called immobilization or blocking means 24, actuable by a user, to immobilize this return 22 during the performance of the test so as to prevent the transmission of the differential tripping order to the circuit breaker D, these immobilization means being different for the two embodiments.

[0038] According to the first embodiment described, the immobilization of this return 22 is controlled by the actuation of the test button 12, a part 12b of which comes into contact with the return 22 so as to immobilize it when the test button 12 is activated, and one end 12a of which cooperates with one 18b of the branches of the spring blade 18 of the test circuit so as to close the so-called second switch 17 of the test circuit in order to carry out the electrical test.

[0039] According to the second embodiment described, the immobilization of this return 22 is controlled by a locking lever 24 specifically provided for this function, this lever 24 being introduced by the user inside the device and brought to bear on the return 22 so as to immobilize it. During an electrical test, the user must therefore act on these two elements, namely the locking lever 24 then the test button 12.

[0040] In these two embodiments, the differential protection device comprises so-called primary means so that the aforementioned return 22 is in a rotationally locked position before the differential mechanism 3 closes, after the test has been carried out.

[0041] In the first embodiment, these means consist in that the test button 12 is in the active position of blocking the return 22 before the closing of the mechanism 3.

[0042] In the second embodiment, these means consist in that the locking lever 24 is in the position for locking the rotation of the gear 22 before the differential mechanism 3 closes.

[0043] In these two embodiments, the differential module also comprises so-called second means to allow the differential mechanism 3 to be closed without a trigger order being given to it by the test circuit during this closing, i.e. the test circuit must be in an open position before this re-closing of the mechanism 3.

[0044] In the first embodiment, these so-called second means comprise a system with two pawls 25, 26, one of which, called the first 25, is supported by the test button 12, and the other 26, called the second, is capable of being driven by the plate 5 of the differential mechanism 3. These two pawls 25, 26 cooperate in the following manner. Actuating the test button 12 in the direction of carrying out the test causes the first pawl 25 to move until it comes into contact with the second pawl 26, after which the push button 12 causes the second pawl 26 to rotate clockwise by cooperation of the two pawls 25, 26. This rotation causes the so-called first switch 16 to close by cooperation of a fork-shaped part 26a of the pawl 26 cooperating with the branch 18a of the spring blade 18.At the same time, this movement of the test button 12 causes the so-called second switch 17 to close, and therefore the test circuit, the other so-called first switch 16 of the test circuit being closed. This results in the opening of the differential mechanism 3, which causes the second pawl 26 to retract relative to the first pawl 25, by driving the pawl 26 by the plate 5 of the differential mechanism 3 in the clockwise direction. The first pawl 25 passes below this second pawl 26, this retraction causing the opening of the first switch 16 of the test circuit by the fact that the so-called first pawl no longer exerts pressure on the end part 18a of the spring blade, which causes this end part to return to the open position under the spring effect of the blade 18.

[0045] After this retraction, and passage of the second pawl 26 above the first pawl 25, the user can close the differential mechanism 3 by actuating the lever N associated with the differential module 3. This produces the rotation of the plate 5 of the differential mechanism 3 in the anti-clockwise direction, the second pawl 26 sliding above the first 25 by means of a part 26b thereof shaped so as to allow this sliding. During this movement, the so-called first switch 16 remains open, because it is released from the pressure produced by the fork-shaped part of the second pawl 26, this pressure being produced during the movement of the first pawl 25.

[0046] This maintenance in the open state of the first switch 16 guarantees that the test circuit will not cause a new triggering of the differential mechanism 3 during the reclosing of the differential mechanism 3.

[0047] According to this embodiment, the first pawl 25 is rotatably mounted relative to the test button 12 and comprises a lug 27 mounted in a notch 28 of corresponding shape provided in this test button 12, said notch 28 having a width slightly greater than that of the lug 27, so as to allow a slight rotation of this pawl 25 inside this notch 28. A return spring 29 is mounted between a fixed part of the push button 12 and the first pawl 25, and is intended to return this first pawl 25 above the second pawl 26 when the test button 12 is released.

[0048] In the second embodiment, these second means consist in that the test button 12 is released, and thus the so-called second switch 17 opens, before the differential mechanism 3 is closed (this reclosure causing the so-called first switch 16 to close). Thus, the test circuit is open during the closing of the differential mechanism 3. This is made possible by the use of the locking lever 24 making it possible to immobilize the return 22 independently of the push button 12, which allows the previously mentioned sequencing.

[0049] The operation of a differential protection device according to the first embodiment described will be described in the following with reference to the figures 1 to 17 .

[0050] On the Figures 6 and 7, the differential protection device is in the open position. The two switches 16, 17 of the test circuit are open, the button 12 of the test circuit is not activated, and the tripping return 22 of the circuit breaker D is resting on the plate 5 of the differential mechanism 3, ready to transmit a tripping order to the circuit breaker D.

[0051] On the figures 8 and 9 , the differential protection device is in the closed position. In the same way as for the previous position, the two switches 16, 17 of the test circuit are in the open position, and the tripping return 22 of the circuit breaker D is resting on the plate 5 of the mechanism 3 of the differential.

[0052] On the Figure 10, in order to carry out an electrical test of the differential mechanism 3, the test button 12 is activated by pushing it into the device by translating the latter towards the interior part of the device. This causes the movement downwards, that is to say towards the interior of the device, of the so-called first ratchet 25 carried by the test button 12. This so-called first ratchet 25 is brought into contact with the so-called second ratchet 26 and the continued introduction of the button 12 into the device causes a slight rotation of the so-called second ratchet 26 in the clockwise direction, the so-called first ratchet 25 being above the so-called second ratchet 26. This rotation of the so-called second ratchet 26 causes the so-called first switch 16 to close, as explained previously.This translational movement of the test button 12 during its activation also causes the second switch 17 of the test circuit, called the test contact, to close by cooperation of the free end 12a of the test button 12 with a branch 18b of the spring blade 18 of the test circuit. As illustrated in the . Figure 11 , the movement of this test button 12 also causes the rotational immobilization of the tripping return 22 of the circuit breaker D by bringing an end part 12b of the button 12 into contact with this return 22. As a result, the circuit breaker D cannot be tripped while this test button 12 is activated.

[0053] On the Figure 12, the closing of the two switches 16, 17 of the test circuit caused the opening of the differential mechanism 3, by the passage in this circuit of a current capable of causing the triggering of the differential mechanism 3. During this opening of the differential mechanism 3, the plate 5 of the differential mechanism 3 rotates clockwise, which causes the retraction of the second pawl 26 relative to the first pawl 25, this second pawl 26 passing above the first pawl 25. This causes the opening of the so-called first switch 16 or so-called self-cutting contact of the test circuit by the fact that this switch is released from the pressure exerted by the so-called first pawl 25, as illustrated on the figure 13 .

[0054] At this stage, the test button 12 must remain pressed when the differential mechanism 3 is open, in order to keep the return 22 immobilized, and to prevent the circuit breaker D from being triggered, due to the open position of the differential mechanism 3.

[0055] As illustrated on the Figure 14 , the differential mechanism 3 is open in the test position, and the tripping return 22 of the circuit breaker D has remained in its position blocked by the test button 12.

[0056] When the differential mechanism 3 is closed, as illustrated in the Figure 15 , and under the effect of the rotation of the plate 5 of the differential mechanism 3 in the anti-clockwise direction, the so-called second pawl 26 slides above the so-called first pawl 25.

[0057] This movement of the pawl 26 does not produce any action on the branch 18a of the spring 18 constituting the so-called self-cutting contact, or first switch 16, and this switch therefore remains open during the re-closing of the mechanism 3. This has the effect of preventing the differential mechanism 3 from reopening.

[0058] As illustrated on the figures 16 and 17 , when the test button 12 is released, the pawl 25 associated with the test button 12 retracts to pass over the pawl 26 of the plate 5, a position allowing a new electrical test to be carried out. And the return 22 returns to bear on the plate 5 of the differential mechanism 3 under the effect of a return spring 30, this position allowing a new tripping of the circuit breaker via the return when a differential fault occurs.

[0059] The operation of a differential protection device according to the second embodiment will be described in the following with reference to: figures 21 to 30 . On the figures 21 and 22 , the differential module is in the open position. The so-called first switch 16, as well as the so-called second switch 17, are in the open position.

[0060] On the figure 23 , the differential module is in the closed position, the so-called first switch 16 is in the closed position, while the so-called second switch 17 is in the open position.

[0061] As illustrated on the figure 24 , the trigger return 22 rests on the plate 5 of the differential mechanism 3.

[0062] As illustrated on the figure 25 , when carrying out the test, a locking lever 24 separate from the test button 12 is introduced into the device so as to immobilize the return. Then, the test button 12 is pressed in order to close the second switch 17 and therefore the test circuit, as illustrated in the figure 26This causes the differential mechanism 3 to open, then the so-called first or self-cutting contact 16 to open, via the plate 5 of the differential mechanism 3, as illustrated in the figure 27 , rotating counterclockwise. In this embodiment, the plate is mechanically connected to the end part of the spring blade and controls the opening and closing of the so-called first switch 16. As illustrated in the figure 28 , the differential mechanism is open, and the gear 22 has remained in its position blocked by the lever 24.

[0063] As illustrated on the figure 29 , when the test button 12 is released, the second contact 17 of the test circuit opens, but the locking lever 24 remains pressed against the return 22.

[0064] Then, as illustrated on the figure 30, the differential mechanism 3 is closed, this causing the closing of the so-called main switch 16, or first, of the test circuit, this switch being driven by the plate.

[0065] Due to the opening of the second switch 17 of the test circuit, the test circuit is cut and can no longer send a trigger order to the relay while the mechanism is closing.

[0066] In this embodiment, it is therefore necessary to release the test button 12 in order to open the second switch 17, before the mechanism closes which will cause the first switch 16 to close. This is made possible by the fact that the test button and the locking means are separate, which makes it possible to leave the locking lever activated when the test button is released.

[0067] By actuating the locking lever 24, the test button 12 can be released in order to open the test circuit. This in fact allows the so-called second mechanism to be closed while the test circuit is open, and thus to prevent a triggering order from being given by the test circuit during this reclosing.

[0068] It is then possible to release the locking lever 24 of the return 22, which allows this return 22 to be released, and to authorize the return of the latter by the spring 30 into a position in which it is supported on the plate 5 of the mechanism 3, and ready to transmit a tripping order to the circuit breaker.

[0069] The invention therefore provides a device of simple design that allows the operation of the differential mechanism to be checked alone, both from an electrical and mechanical point of view, without opening the power contacts of the circuit breaker.

[0070] In fact, the first implementation requires six additional parts compared to a circuit breaker that does not allow this function, namely (state these additional parts), while the second implementation requires 3 or 5 additional parts (state these additional parts).

[0071] It should be noted that in the second embodiment, the return can be activated, for example, by a push button integrated into the circuit breaker or by a tool independent of the device operated by the user.

[0072] It should be noted that testing the circuit breaker tripping remains possible in the first implementation, if the user releases the test button when the differential mechanism is open.

[0073] Both a test of the differential mechanism 3 and a test of the associated circuit breaker D will then have been carried out, as is done in the prior art.

[0074] Similarly, in the second embodiment, it is possible to carry out the test until the circuit breaker trips, when the locking lever is removed while the differential mechanism is still open.

[0075] It should be noted that the implementation of the invention requires that the two handles of the circuit breaker and the differential mechanism respectively are not integral, as is generally the case in this type of device.

[0076] Therefore, carrying out the differential test will require removing the mechanical connection between the two levers, when there is a mechanical connection between these two levers.

[0077] Of course, the invention is not limited to the embodiments described and illustrated which have been given only as an example.

[0078] The invention is applicable to any device comprising a differential module associated with at least one circuit breaker module, whether this device is in the form of several independent modules housed respectively in different boxes, or in the form of a single module housing the different functions in the same box.

Claims

1. A differential electrical switchgear device housed in an insulated enclosure containing: - a first cut-off compartment comprising at least: • an electrical circuit with a fixed contact and a moving contact, • a first control mechanism for closing and opening the aforementioned contacts, operated manually by a joystick and automatically, - a second compartment with differential protection comprising: • means for detecting a differential fault in the circuit to be protected, • means for triggering a so-called second control mechanism (3) controlled by the aforementioned detection means and capable of causing this second mechanism (3) to open when such a fault occurs, • means for transmitting the triggering command to the first-mentioned control mechanism, and • electrical test equipment (11) for the differential function designed to trigger the second mechanism (3) when activated, said test means comprising a test circuit and being actuated by test control means, in which these transmission means comprise a return (22) mechanically connected to the two aforementioned mechanisms (3) so as to be able to transmit the triggering order sent by the differential triggering means to the second mechanism (3), to the first mechanism, characterised in that this apparatus comprises means (12, 24) for immobilising this transmission (22), activated when the aforementioned test is carried out, the immobilisation means being configured to bear against the transmission, so as to keep the transmission immobilised and thus prevent the transmission of this triggering order to the first mechanism (3) for at least part of the duration of the test.

2. A differential electrical switchgear device as claimed in claim 1, characterised in that it comprises so-called first means for immobilising this return (22) during the test at least until the differential mechanism (3) is closed again.

3. A differential electrical switchgear device according to claim 1 or 2, characterised in that it comprises so-called second means enabling the differential mechanism (3) to be closed again, the test circuit being in the open position.

4. A differential electrical switchgear device according to any one of the preceding claims, characterised in that these means of controlling the differential test comprise a so-called test button (12) capable of actuated by a user and mounted so as to move in translation with respect to the casing B of the device between two positions corresponding respectively to an open position and to a closed position of the test circuit.

5. A differential electrical switchgear device according to any one of the preceding claims, characterised in that the means (24) for immobilising the return (22) are carried by the control means (12) of the differential test and actuated when the aforementioned control means (12) are activated.

6. A differential electrical switchgear device as claimed in claim 5, characterised in that it comprises means for preventing the reclosing of a so-called first switch (16) of the test circuit during the reclosing of the so-called second mechanism (3) after a differential test has been carried out.

7. A differential electrical switchgear device according to claim 6, characterised in that these means for preventing the reclosing of the so-called first switch (16) comprise means for returning the so-called first switch (16) to the open position, and in that the differential mechanism (3) or second switchgear comprises a plate (5), this plate (5) comprising a part (26) capable of being driven by the control means (12) of the test when they are activated, so as to close the so-called first switch (16), and to retract when the differential mechanism (3) opens, so as to allow the return of the first switch (16) in the open position, and to allow the differential mechanism (3) to be reclosed, the first-mentioned switch (16) being held in the open position.

8. A differential electrical switchgear device according to claims 4 and 7, characterised in that these means for preventing the reclosing of the so-called first switch (16) comprise a so-called first pawl (25) mounted so as to rotate with respect to the test button (12) and a so-called second pawl (26) integral with the plate (5) of the second mechanism (3), the first pawl (25) being returned above the second pawl (26) by a spring (29) at the start of actuation of the test button (12) and then, during actuation of the test button (12), the pawl (25) driving the plate (5) of the second mechanism (3) in the direction of opening of the second mechanism (3), the second pawl (26) being capable of retracting to pass over the first pawl (25) when the second mechanism (3) is opened, this retraction allowing the first switch (16) to be opened and being maintained when the second mechanism (3) is reclosed so as not to reclose the first switch (16), this first pawl (25) being capable of retracting when the test button (12) is released in order to pass over the second pawl (26) again, so as to make it possible to carry out a new test.

9. A differential electrical switchgear device according to any one of claims 1 to 4, characterised in that the return immobilisation means (22) are carried by locking means (24) which can be actuated by the user and are independent of the differential test control means (12).

10. A differential electrical switchgear device according to claims 3 and 9, characterised in that the so-called first switch (16) is controlled by the differential mechanism (3) and these so-called second means comprise the following sequence for the performance of the test by the user: the blocking means (24) are brought into the active blocking position, then the test control means (12) are activated, which causes a second switch (17) to close, the first switch (16) being returned to the closed position, after which the so-called second mechanism (3) opens under the effect of the test circuit closing, which causes the first switch (16) initially closed to open, then the test control means (12) are deactivated, which causes the second switch (17) to open and the so-called second mechanism (3) to close again, which causes the first switch (16) to close.

11. A differential electrical switchgear device according to claim 9 or 10, characterised in that the locking means (24) comprise a tool external to the switchgear or a push-button integrated into the switchgear.

12. A differential electrical switchgear device according to claim 10 or 11, characterised in that the two aforementioned switches (16, 17) are formed respectively by two free ends (18a, 18b) of a leaf spring (18) cooperating respectively with two fixed points of the test circuit.

13. Electrical switchgear according to claims 8 and 12, characterised in that the so-called second pawl (26) comprises a first portion (26a) shaped like a fork able to cooperate with the end portion (18a) of the leaf spring (18) belonging to the first switch (16) and a second portion (26b) able to slide over the first pawl (25) when the so-called second mechanism (3) is closed again.

14. A differential electrical switchgear device according to any one of the preceding claims, characterised in that it is a single-pole and neutral differential circuit breaker.

15. A differential electrical switchgear device according to any one of the preceding claims, characterised in that the first and second mechanisms (3) each comprise a plate (5), the transmission (22), the plate of the first mechanism (3) and the plate (5) of the second mechanism (3) are mounted about the same axis Y, and the plate (5) of the differential mechanism (3) comprises a protuberance (23) adapted to cooperate with the aforementioned transmission (22).