CN107919255B

CN107919255B - Differential electric switch device

Info

Publication number: CN107919255B
Application number: CN201710815264.6A
Authority: CN
Inventors: Y.贝林
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2016-10-11
Filing date: 2017-09-11
Publication date: 2021-10-01
Anticipated expiration: 2037-09-11
Also published as: FR3057389A1; FR3057389B1; EP3309813A1; CN107919255A

Abstract

The invention relates to a differential electrical switching device, housed in an insulating casing containing at least one electrical circuit with fixed contacts and moving contacts, a first mechanism for controlling the closing and opening of the contacts with manual control using a manoeuvring handle and with automatic control, means for detecting a differential fault, means for tripping a second control mechanism (3), means for transmitting a tripping command to the first control mechanism, and means for electrically testing the differential function. The device is characterized in that the transmission means comprise a transmitter (22) mechanically linked to the two mechanisms (3) to be able to transmit to the second control mechanism (3) a tripping command sent by the differential tripping means, and in that the device comprises means for fixing the transmitter, activated when the test is performed, to prevent the transmission of the tripping command to the first mechanism during at least part of the duration of the test.

Description

Differential electric switch device

Technical Field

The present invention relates to a differential electrical switching device housed in an insulating casing enclosing a first switching chamber containing at least one electrical circuit with fixed contacts and moving contacts, a first mechanism for controlling the closing and opening of the above-mentioned contacts with manual control using a manoeuvring handle and with automatic control, a second differential protection chamber containing means for detecting differential faults in the electrical circuit to be protected, means for tripping a second control mechanism capable of causing the opening of the mechanism when such a fault occurs, means for transmitting a tripping command to the first control mechanism, and means for electrically testing the differential function intended to cause the tripping of the second mechanism when activated, said testing means being actuated by test control means.

Background

In the field of differential electrical switching devices, differential functional testing is mandatory for verifying the operation of a differential electrical switching device once a month.

In the known device, the checking of the operation of the differential function comprises opening the power contacts.

Now, in some applications, switching power contacts during testing is unacceptable for service continuity, safety and cost reasons, as the process implies terminating and then restarting the application or process.

Disclosure of Invention

The present invention addresses these problems and provides a differential electrical switching apparatus having a simple design that enables differential electrical testing to be performed without causing service continuity interruptions.

The present invention relates to a differential electrical switching apparatus of the type mentioned previously, the apparatus being characterized in that the transmission means comprise a transmitter mechanically linked to the two mechanisms to be able to transmit a tripping command sent by the differential tripping means to the second mechanism to the first mechanism, and in that the apparatus comprises means for fixing the transmitter, which are activated when the test is performed, to prevent the transmission of the tripping command to the first mechanism during at least part of the duration of the test.

According to a particular feature, the device comprises first means for fixing the transmitter during the test until the differential mechanism is reclosed.

According to another feature, the device comprises second means for enabling the differential mechanism to be reclosed, the test circuit being in the open position.

According to another feature, these differential test control means comprise a push-button, called test button, which can be activated by the user and is mounted so as to be free to move in translation with respect to the casing of the device between two positions, corresponding respectively to the open position and to the closed position of said second switch.

According to a particular embodiment, the means for fixing the conveyor are carried by the differential test control means and are activated when said control means are activated.

According to another feature, the device comprises means for preventing the first switch of the test circuit from reclosing during reclosing of the second mechanism after the differential test has been performed.

According to another feature, these means for preventing the reclosing of the first switch comprise means for returning the first switch to the open position, and the differential or second mechanism comprises a plate comprising a member that can be actuated by the test control means when they are actuated, to close the first switch, and to retract when the differential mechanism is open, so as to permit the first switch to return to the open position, and to cause the differential mechanism to reclose, the first switch remaining in the open position.

According to another feature, these means for preventing the reclosing of the first switch comprise a first pawl rotatably mounted with respect to the test button and a second pawl engaged to the plate of the second mechanism, so that at the start of the actuation of the test button, said first pawl is returned by a spring above the second pawl, the pawl driving the plate of the second mechanism in the opening direction of the second mechanism during the actuation of the test button, at the moment of the opening of this second mechanism, the second pawl being retractable to pass over the first pawl, this retraction enabling the first switch to open and to be maintained when the second mechanism is reclosed, so as not to reclose the first switch, this first pawl being retractable when the test button is released to pass again over the second pawl, so that a new test can be performed.

According to another embodiment, the means for fixing the conveyor are carried by a blocking device, which is activated by the user and is independent of the differential test control means.

According to a particular feature, the first switch is controlled by the differential mechanism, the second devices comprising the following programming for the execution of the test by the user: the blocking device is brought into an active blocking position and then the test control device is activated, which results in the closure of the second switch, the first switch returning to the closed position, after which the second mechanism opens under the effect of the closure of the test circuit, which results in the opening of the first switch which was initially closed, and then the test control device is closed, which results in the opening of the second switch and the reclosing of the second mechanism, which results in the closure of the first switch.

According to another feature, the blocking means comprise a tool external to the device or a button integrated in the device.

According to another feature, the two above-mentioned switches are respectively formed by two free ends of the leaf spring interacting respectively with two fixed points of the test circuit.

According to another feature, the second pawl comprises: a first fork-shaped part able to interact with the end of the leaf spring belonging to the first switch, and a second part able to slide over the first pawl when the second mechanism is reclosed.

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

According to another feature, the first and second means each comprise a plate, a conveyor, the plate of the first means and the plate of the second means being mounted around the same axis, the plate of the differential means comprising a projection able to interact with said conveyor.

Drawings

However, other advantages and features of the present invention will become apparent in the following detailed description, given by way of example only and in which:

fig. 1 to 17 relate to a first embodiment of the invention, while fig. 18 to 30 relate to a second embodiment of the invention;

fig. 1 is a perspective view including a sectional view of a differential circuit breaker according to a first embodiment of the present invention;

FIG. 2 is a perspective view of the same device with a portion of its housing removed to reveal its interior;

FIG. 3 is a partial perspective view showing a portion of the mechanism to which the present invention relates;

FIG. 4 is an exploded view of the previous view;

FIG. 5 is a view similar to FIG. 3, from the other side of the device;

fig. 6 and 7 are partial plan views respectively showing the interior of the device, viewed from two opposite sides of the device, with the circuit breaker in the open position;

figures 8 and 9 are the same views as the previous figures, with the device in the closed position;

FIGS. 10 to 17 are partial plan or perspective views showing the mechanism during the performance of electrical tests;

fig. 18 is an exploded view of a portion of the mechanism according to the second embodiment of the present invention;

FIGS. 19 and 20 show this same mechanism in two different orientations;

FIGS. 21 and 22 are fragmentary plan views respectively showing the interior of the device as viewed from two opposite sides of the device, with the device in an open position;

figures 23 and 24 are two partial plan and perspective views respectively showing the mechanism of the circuit breaker in the closed position; and

fig. 25 to 30 are partial plan or perspective views showing this same mechanism during the performance of electrical tests.

Detailed Description

In fig. 1 it can be seen that an apparatus comprising a differential module 2 associated with a circuit breaker 1 is shown, this apparatus being of the unipolar and neutral type, but also of the bipolar, tripolar and neutral type. In the subsequent figures, only the mechanism 3 of the differential module 2 is shown.

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

The phase circuit includes a movable contact electrically connected to the upstream terminal through a bimetallic trip device, and a fixed contact connected to an excitation coil of an electromagnetic trip device. The first arc extinguishing chamber is arranged between the electromagnetic trip device and the base of the housing and comprises a stack of metal arc deionization plates interposed between said contacts. The neutral circuit is equipped with a fixed contact and a movable contact electrically connected to the two upstream and downstream terminals, respectively, and with a second arc-extinguishing chamber. The neutral circuit is located to the left of the phase circuit and has no thermomagnetic trip device.

The two movable contacts are actuated, both manually controlled using the operating handle M and automatically using a bimetallic trip and a coil electromagnetic trip, by a first mechanism not shown in fig. 1.

The second differential module 2 is located to the right of the first module 1 and encloses a differential converter having a secondary winding connected to a trip relay which interacts with a second mechanism 3 having a reset manoeuvring handle N. This second mechanism 3 is coupled to the first mechanism of the circuit breaker by a mechanical link that permits action to be taken to trip the circuit breaker when a differential trip command is transmitted through the relay, and continued action to reset 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 linked by A breakable mechanical link to A respective manoeuvring handle N, and A trip lever 8 which can be actuated in the event of A fault by means of A relay to cause the breaking of the mechanical link and the rotation of plate 5.

In this way, and in a manner known per se, when an insulation fault occurs in the circuit to be protected (in which the circuit breaker is located), the differential detector energizes the coil of the relay, which causes the differential control mechanism and the mechanism of the circuit breaker to trip in series through the mechanical link.

The differential converter includes a magnetic loop carrying a primary phase winding, a primary neutral winding, and a secondary measurement winding. A ground fault causes an imbalance between the primary current flowing through the primary winding and an induced voltage is generated across the terminals of the secondary winding to energize the trip relay.

In a manner also known per se, this second mechanism 3 is equipped with a device 11 for electrically testing the differential mechanism, which is housed in the second module 2 and has a test button 12 intended to be actuated by sliding between a raised rest position and a depressed operating position. The test device 11 further comprises a resistor 13 inserted in a test circuit connected between the interconnection tab of the link conductor 14 of the phase circuit and the connection conductor 15 of the primary neutral winding. The resistor 13 is connected in series to a first switch 16, which is activated by the second mechanism 3, and a second switch 17, which is controlled by the test button 12. The first switch 16 is formed by an end 18a of a leaf spring 18 carried on the link conductor 14 in the closed position. The test or second switch 17 comprises an end 18b of a leaf spring 18 intended to interact with the terminal wire 19 of the resistor 13 when the test button 12 is in the depressed position.

Both ends of the test circuit 11 are thus connected to the downstream sides of the phase and neutral contacts simultaneously.

In a manner known per se in differential test devices from the prior art, the resistor 13 is placed in the circuit when the two

switches

16, 17 are closed, i.e. in the standby state of the second mechanism 3, and when the test button 12 is in the depressed operating position. This results in a test current in the resistor, which is detected by the differential converter, causing the second mechanism 3 to trip, and then causing the first mechanism of the circuit breaker D to trip. The pivoting of the rotary plate 5 of the differential mechanism 3 causes the first switch 16 to open automatically, resulting in the interruption of the test current in the resistor 13, even if the test button 12 remains in the depressed position.

According to the invention, the apparatus comprises means for performing an electrical test of the differential trip device by tripping its mechanism without tripping the mechanism of the circuit breaker D.

For each of the two embodiments described and illustrated in figures 1 to 17 for the first embodiment and in figures 18 to 30 for the second embodiment, these means comprise a conveyor 22 rotatably mounted about an axis Y fixed with respect to the casing B of the device, said conveyor 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 to trip the latter by means of the pin 9 engaged to said conveyor 22. For this purpose, the plate 5 of the differential mechanism 3, the plate of the mechanism of the circuit breaker and the conveyor 22 are rotatably mounted about the same axis Y, the plate 5 of the differential mechanism 3 comprising a protrusion 23 extending parallel to the above-mentioned axis of rotation Y and able to interact with the conveyor 22 so as to enable the plate of the circuit breaker D to be driven by the plate 5 of the differential mechanism 3 through the conveyor 22.

These means also comprise blocking means 24, actuatable by the user, for fixing the transmitter 22 when performing the test, to prevent the differential trip command from being transmitted to the circuit breaker D, these fixing means being different for the two embodiments.

According to the first described embodiment, the fixing of this conveyor 22 is controlled by actuating the test button 12, the part 12b of the test button being in contact with the conveyor 22 to fix the conveyor when the test button 12 is actuated, and the end 12a of the test button interacting with one of the branches 18b of the leaf spring 18 of the test circuit to close the second switch 17 of the test circuit for the purpose of performing an electrical test.

According to the second described embodiment, the fixing of the conveyor 22 is controlled by a blocking means 24 specifically provided for this purpose, which blocking means 24 is introduced inside the device by the user and made to bear on the conveyor 22 to fix the latter. During the electrical test, the user must therefore act on both elements, namely the blocking means 24 and then the test button 12.

In both embodiments, the differential protection device comprises a first means, so that the above-mentioned transmitter 22 is in the rotation blocking position before reclosing the differential mechanism 3 after the test has been performed.

In a first embodiment, these means consist in the test button 12 being in the active position for blocking the conveyor 22 before reclosing the mechanism 3.

In the second embodiment, these means consist in the blocking means 24 being in a position to block the conveyor 22 in rotation before reclosing the differential 3.

In both embodiments, the differential module also comprises second means to enable the differential mechanism 3 to be reclosed without providing a tripping command to the differential mechanism by the test circuit during this closure, i.e. the test circuit must be in the open position before reclosing of the mechanism 3.

In a first embodiment, these second means comprise a system with a first pawl 25, a second pawl 26, the first pawl 25 being supported by the test button 12, the second pawl 26 being able to be driven by the plate 5 of the differential 3. These first pawl 25, second pawl 26 interact in the following manner. Actuation of the test button 12 in the direction to perform the test causes the first pawl 25 to displace until the first pawl 25 contacts the second pawl 26, after which the test button 12 causes the second pawl 26 to rotate in a clockwise direction through interaction of the first and

second pawls

25, 26. This rotation causes the first switch 16 to close by the interaction of the forked part 26a of the pawl 26 with the limb 18a of the leaf spring 18. At the same time, this displacement of the test button 12 causes the second switch to close, and thus the test circuit to close, the other first switch 16 of the test circuit to close. The differential mechanism 3 is therefore open, which leads to the following situation: the pawl 26 is driven in a clockwise direction by the plate 5 of the differential 3, so that the second pawl 26 is retracted with respect to the first pawl 25. The first pawl 25 passes under the second pawl 26, this retraction causing the first switch 16 of the test circuit to open by virtue of the fact that: the first pawl no longer applies pressure to the end 18a of the leaf spring, which causes it to return to the open position under the spring effect of the leaf spring 18.

After this retraction and the passage of the second pawl 26 over the first pawl 25, the user can reclose the differential mechanism 3 by actuating the manoeuvring handle N associated with the differential module 3. This produces a rotation of plate 5 of differential 3 in the anticlockwise direction, second pawl 26 sliding over first pawl 25 by means of a part 26b of the second pawl, said part being shaped so as to be able to cause this sliding. During this movement, the first switch 16 remains open, since the pressure generated by the fork-shaped part of the second pawl 26, which pressure is generated when the first pawl 25 is displaced, is relieved.

Maintaining the first switch 16 in the open state in this way ensures that the test circuit does not cause the differential mechanism 3 to trip again during the reclosing of the differential mechanism 3.

According to this embodiment, the first pawl 25 is rotatably mounted with respect to the test button 12 and comprises a tab 27 mounted in a correspondingly shaped recess 28 provided in the test button 12, said recess 28 having a slightly larger width than the tab 27 to allow the pawl 25 to rotate slightly inside the recess 28. A return spring 29 is mounted between the fixed part of the test button 12 and the first pawl 25 and is intended to return the first pawl 25 above the second pawl 26 when the test button 12 is released.

In the second embodiment, these second means consist in that the test button 12 is released and the second switch 17 is therefore opened before the differential 3 is reclosed (which closes the first switch 16). The test circuit is therefore open during the closing of the differential mechanism 3. This is made possible by the use of blocking means 24 which make it possible to fix the conveyor 22 independently of the test button 12, which enables the previously mentioned serialization.

The operation of the differential protection device according to the first described embodiment will be described below with reference to fig. 1 to 17.

In fig. 6 and 7, the differential protection device is in the open position. The two

switches

16, 17 of the test circuit are open, the test button 12 of the test circuit is not activated and the transmitter 22 for tripping the circuit breaker D is carried on the plate 5 of the differential mechanism 3, ready to transmit a tripping command to the circuit breaker D.

In fig. 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 conveyor 22 for tripping the circuit breaker D is carried on the plate 5 of the differential mechanism 3.

In fig. 10, in order to perform an electrical test of the differential mechanism 3, the test button 12 is actuated by pressing it into the device via a translational movement of the test button in the direction of the interior of the device. This results in a downward displacement, i.e. into the device, of the first pawl 25 carried by the test button 12. The first pawl 25 contacts the second pawl 26 and continued introduction of the test button 12 into the device causes the second pawl 26 to rotate slightly in a clockwise direction, the first pawl 25 being above the second pawl 26. This rotation of the second pawl 26 causes the first switch 16 to close, as previously described. This translational displacement of the test button 12 upon its actuation also causes the second switch 17 of the test circuit to close, called test contact, by the free end 12a of the test button 12 interacting with the branch 18b of the leaf spring 18 of the test circuit. By having the end 12b of the test button 12 bear on the conveyor 22, as shown in fig. 11, the displacement of the test button 12 also results in a rotational fixing of the conveyor 22 for tripping the circuit breaker D. This results in the circuit breaker D not being tripped when the test button 12 is actuated.

In fig. 12, the closure of the two

switches

16, 17 of the test circuit has caused the differential mechanism 3 to open, by the current that can cause the differential mechanism 3 to trip flowing through the circuit. When the differential mechanism 3 is opened in this way, the plate 5 of the differential mechanism 3 rotates in a clockwise direction, which causes the second pawl 26 to retract with respect to the first pawl 25, the second pawl 26 passing over the first pawl 25. This results in the first switch 16 or automatic switch contact of the test circuit being opened, as shown in fig. 13, by virtue of the fact that the first switch relieves the pressure exerted by the first pawl 25.

At this stage, the test button 12 must remain activated when the differential mechanism 3 is open, in order to keep the conveyor 22 fixed and prevent the circuit breaker D from tripping due to the open position of the differential mechanism 3.

As shown in fig. 14, the differential mechanism 3 is open in the test position and the conveyor 22 for tripping the circuit breaker D is held in its blocking position by the test button 12.

When the differential 3 is re-closed, as shown in fig. 15, and under the effect of the plate 5 of the differential 3 rotating in the anticlockwise direction, the second pawl 26 slides over the first pawl 25.

This movement of the second pawl 26 does not have any effect on the branch 18a of the spring 18 forming the automatic switch contact or first switch 16 and the switch therefore remains open during reclosing of the mechanism 3. This has the effect of preventing the differential mechanism 3 from reopening.

As shown in fig. 16 and 17, when the test button 12 is released, the first pawl 25 associated with this test button 12 retracts to pass again over the second pawl 26 of the plate 5, a position which enables the electrical test to be re-performed. The conveyor 22 also returns to bear on the plate 5 of the differential mechanism 3, under the effect of the return spring 30, a position such that, in the event of a differential fault, the circuit breaker can be tripped again by the conveyor.

The operation of the differential protection device according to the second embodiment will be described below with reference to fig. 21 to 30.

In fig. 21 and 22, the differential module is in the open position. The first switch 16, as well as the second switch 17, are in the open position.

In fig. 23, the differential module is in the closed position, the first switch 16 is in the closed position, and the second switch 17 is in the open position.

As shown in fig. 24, the trip transmitter 22 is carried on the plate 5 of the differential mechanism 3.

As shown in fig. 25, when the test is performed, the blocking device 24, which is separated from the test button 12, is introduced into the apparatus to fix the conveyor. The test button 12 is then pressed to close the second switch 17 and thus the test circuit, as shown in fig. 26. This causes the differential 3 to open, by the rotational travel of the plate 5 of the differential 3 in the anticlockwise direction (as shown in figure 27), and then the first or automatic switch contact 16 to open. Specifically, in this embodiment, the trigger is mechanically linked to the end of the leaf spring and controls the opening and closing of the first switch 16. As shown in fig. 28, the differential mechanism is open and the conveyor 22 is held in its blocking position by the blocking means 24.

When the test button 12 is released, the second contact 17 of the test circuit opens, while the blocking device 24 remains carried on the conveyor 22, as shown in fig. 29.

Then, as shown in fig. 30, the differential mechanism 30 is re-closed, which causes the main or first switch 16 of the test circuit, which is driven by the board, to close.

Due to the opening of the second switch 17 of the test circuit, during reclosing of the mechanism, the test circuit is switched off and is no longer able to send a trip command to the relay.

In this embodiment it is therefore necessary to release the test button 12 to open the second switch 17 before the mechanism recloses (which will result in the closure of the first switch 16). This is made possible by the fact that the test button and the blocking means are separated, which makes it possible to maintain the blocking means activated when the test button is released.

Due to the actuation of the blocking device 24, the test button 12 may be released to open the test circuit. This enables, in particular, the second mechanism to be reclosed when the test button is opened, thus preventing a tripping command from being given by the test circuit during this reclosing.

The blocking means 24 of the conveyor 22 can then be released, which makes it possible to release the conveyor 22 and, by means of the spring 30, to allow the return of the conveyor to a position in which it is carried on the plate 5 of the mechanism 3 and is ready to transmit a trip command to the circuit breaker.

According to the invention, the device thus produced has a simple design, both from an electrical point of view and from a mechanical point of view, so that the operation of the differential mechanism can be checked separately, without opening the power contacts of the circuit breaker.

Specifically, the first embodiment requires six additional components with respect to the circuit breaker that are not capable of providing this function, i.e. (these additional components are listed), while the second embodiment requires 3 or 5 additional components (these additional components are listed).

It will be noted that in the second embodiment, the conveyor will be able to be actuated, for example, by a button integrated in the circuit breaker or even a tool independent of the device and operated by the user.

It will be noted, however, that the test for tripping the circuit breaker may still be in the first embodiment if the user releases the test button when the differential mechanism is open.

Both the test of the differential mechanism 3 and the test of the associated circuit breaker D are then carried out, as is done in the prior art.

Likewise, in the second embodiment, when the blocking device is disengaged while the differential mechanism is still open, a test can be performed until the circuit breaker trips.

It will be noted that embodiments of the present invention require that the two operating handles (of the circuit breaker and of the differential mechanism respectively) are not joined together, as is often the case in this type of device.

For this reason, performing a differential test would require removing the mechanical link between the two joysticks when the mechanical link exists between the two joysticks.

The invention is of course not limited to the embodiments described and shown, which are given by way of example only.

The invention is applicable to any device comprising a differential module associated with at least one circuit breaker module, whether in the form of a plurality of independent modules housed respectively in different housings or even in the form of a single module housing a plurality of functions in the same housing.

On the contrary, the invention encompasses all technical equivalents of the means described, as well as combinations thereof, if these are implemented according to the spirit thereof.

Claims

1. A differential electrical switching apparatus, housed in an insulating casing which encloses a first switching chamber containing at least one electrical circuit with fixed contacts and movable contacts, a first mechanism for controlling the closing and opening of the above-mentioned contacts with manual control using a manoeuvring handle and with automatic control, a second differential protection chamber containing means for detecting differential faults in the electrical circuit to be protected, means for tripping the second mechanism, capable of causing the opening of a second mechanism when such a fault occurs and controlled by the above-mentioned means, transmission means for transmitting tripping commands to the first mechanism, and test circuits for electrical testing of the differential functions, intended to cause the tripping of said second mechanism when they are activated, said test circuits being actuated by test control means,

characterized in that the transmission means comprise a transmitter (22) mechanically linked to the first and to the second mechanism to be able to transmit to said first mechanism a tripping command sent by the differential tripping means to the second mechanism (3), and in that the differential electric switching device comprises means for fixing the transmitter (22) which are activated when said electric test is carried out, to prevent the transmission of the tripping command to said first mechanism during at least a portion of the duration of said electric test.

2. A differential electric switching device according to claim 1, characterized in that it comprises first means for fixing the transmitter (22) during said electric test until said second mechanism (3) is reclosed.

3. A differential electrical switching apparatus according to claim 1, characterized in that it comprises second means enabling reclosing of the second mechanism (3), the test circuit being in an open position.

4. A differential electric switching device according to any one of the preceding claims, characterized in that the test control means comprise a push button, called test button (12), which can be actuated by a user and is mounted so as to be free to move in translation with respect to the casing (B) of the differential electric switching device between two positions, which correspond respectively to the open position and the closed position of the second switch (17) of the test circuit.

5. A differential electrical switching apparatus according to claim 4 wherein the means for securing the conveyor (22) is carried by the test control means and is actuated upon activation of the test control means.

6. A differential electrical switching apparatus according to claim 5, characterized in that it comprises means for preventing the first switch (16) of the test circuit from reclosing during reclosing of the second mechanism (3) after a differential test has been performed.

7. A differential electrical switching apparatus according to claim 6 wherein the means for preventing reclosing of the first switch (16) comprises means for returning the first switch (16) to the open position and the second mechanism (3) comprises a plate (5) containing components which can be actuated by the test control means on their actuation to close the first switch (16) and to retract when the second mechanism (3) is open to permit return of the first switch (16) to the open position and to cause reclosing of the second mechanism (3), the first switch (16) remaining in the open position.

8. Differential electrical switching device according to claim 7, characterized in that these means for preventing the reclosing of the first switch (16) comprise a first pawl (25) rotatably mounted with respect to the test button (12) and a second pawl (26) engaged to the plate (5) of the second mechanism (3), so that at the beginning of the actuation of the test button (12) the first pawl (25) returns by means of a spring (29) over the second pawl (26), during the actuation of the test button (12) the first pawl (25) drives the plate (5) of the second mechanism (3) in the opening direction of the second mechanism (3), at the moment of opening of the second mechanism (3) the second pawl (26) being retractable to pass over the first pawl (25), the retraction enables the first switch (16) to be opened and maintained when the second mechanism (3) is re-closed so as not to re-close the first switch (16), the first pawl (25) being retractable when the test button (12) is released to pass again over the second pawl (26) so that a new test can be performed.

9. A differential electrical switching apparatus according to claim 4, characterized in that the means for fixing the conveyor (22) are carried by blocking means (24) actuated by the user and independent of the test control means.

10. A differential electric switching device according to claim 9, characterized in that said first switch (16) is controlled by said second mechanism (3), these second means comprising the following sequence for performing a test by a user: -bringing the blocking device (24) in an active blocking position, then activating a test control device, which causes the second switch (17) to close, the first switch (16) returning to the closed position, after which the second mechanism (3) opens under the effect of the closure of the test circuit, which causes the first switch (16), which was initially closed, to open, then the test control device fails, which causes the second switch (17) to open, and the second mechanism (3) to re-close, which causes the first switch (16) to close.

11. A differential electrical switching apparatus according to claim 9, characterized in that the blocking means (24) comprises a tool external to the apparatus or a push button integrated in the differential electrical switching apparatus.

12. A differential electrical switching device according to claim 6, characterized in that the first and second switches are formed by two free ends (18a, 18b) of a leaf spring (18) interacting with two fixed points of the test circuit, respectively.

13. A differential electrical switching device according to claim 8 wherein the second pawl (26) comprises: -a first fork-shaped part (26a) able to interact with an end (18a) of a leaf spring (18) belonging to a first switch (16), and-a second part (26b) able to slide on said first pawl (25) when said second mechanism (3) is reclosed.

14. A differential electrical switching apparatus according to any of claims 1-3 wherein the differential electrical switching apparatus is a single pole and neutral differential circuit breaker.

15. A differential electric switching device according to any one of the preceding claims 1-3, characterized in that the first and second mechanism (3) each comprise a plate (5), said conveyor (22), the plates of the first and second mechanism (3) being mounted about the same axis Y, the plate (5) of the second mechanism (3) comprising a projection (23) capable of interacting with the conveyor (22).