CH719477A2 - Differential lock for electrical differential protection device and electrical differential protection device. - Google Patents

Abstract

The invention relates to a differential lock (1) for an electrical device for differential protection comprising a trigger (6) for triggering in a triggered position said switching lock of the electrical device for differential protection in the event of a differential fault, said trigger ( 6) being movable between an armed position (PA) in which said trigger (6) is arranged to be at a distance from the switching lock and the triggered position in which said trigger (6) activates the switching lock. Said differential lock (1) is characterized in that said trigger (6) is capable and intended to be moved from the triggered position to the armed position (PA) under the effect of the movement of a first movable contact in the event of opening of a first pair of contacts and a second pair of contacts, said differential lock (1) comprises reset means (8) capable and intended to be moved under the effect of the movement of a second movable contact in case of opening of said first pair of contacts and said second pair of contacts and being configured to move a push button (5) of an electromagnetic relay (4) from an extended position to a retracted position (PR) in case opening of said first pair of contacts and said second pair of contacts. The invention also relates to an electrical differential protection device.

Description

The present invention relates to the field of differential locks for electrical differential protection devices and relates to the field of electrical differential protection devices comprising such differential locks, for example molded case differential circuit breakers.

[0002] Voltage-independent electrical differential protection devices in modular format use dedicated parts which are arranged so as to create a reset kinematics of the electromagnetic relay, when the electrical differential protection device is in the closed position, c i.e. when the contact pairs are open. These parts in the form of springs and moving parts require space dedicated to their operation, which is a disadvantage.

[0003] We thus already know voltage-independent differential circuit breakers in modular format capable of resetting the electromagnetic relay, but which do not have a differential lock.

[0004] The present invention aims to overcome these drawbacks and to propose a solution making it possible to reset an electromagnetic relay and to reset a differential lock following the detection of a differential fault.

[0005] To this end, the invention relates to a differential lock for an electrical differential protection device, said electrical differential protection device comprising at least: a first current line comprising at least a first pair of contacts comprising a first movable contact and a first fixed contact, a second current line comprising at least a second pair of contacts comprising a second movable contact and a second fixed contact, a switching lock arranged to switch said first pair of contacts and said second pair of contacts, a relay electromagnetic comprising a push button, the electromagnetic relay being configured to be closed in the absence of a differential fault in a closed position in which the push button is in a retracted position and to be opened in the event of a differential fault in a position of opening in which the push button is in an extended position, so as to trigger a trigger of said differential lock, the differential lock comprising at least: a trigger for triggering said switching lock of the electrical differential protection device in a triggered position in the event of a differential fault, said trigger being movable between an armed position in which said trigger is arranged to be at a distance from the switching lock and the triggered position in which said trigger activates the switching lock, said differential lock is characterized in that that: said trigger is capable and intended to be moved from the triggered position to the armed position under the effect of the movement of the first movable contact in the event of opening of said first pair of contacts and said second pair of contacts, said lock differential comprises reset means capable and intended to be moved under the effect of the movement of the second movable contact in the event of opening of said first pair of contacts and said second pair of contacts and being configured to move the push button of the relay electromagnetically from the extended position to the retracted position in the event of opening of said first pair of contacts and said second pair of contacts.

[0006] The invention also relates to an electrical device for differential protection, preferably a differential circuit breaker, said electrical device for differential protection comprising at least - a first current line comprising at least a first pair of contacts comprising a first movable contact and a first fixed contact, - a second current line comprising at least a second pair of contacts comprising a second movable contact and a second fixed contact, - a switching lock arranged to switch said first pair of contacts and said second pair of contacts, - an electromagnetic relay comprising a push button, the electromagnetic relay being configured to be closed in the absence of a differential fault in a closed position in which the push button is in a retracted position and to be opened in the event of a differential fault in a position opening in which the push button is in an extended position, so as to trigger a trigger of said differential lock, said electrical differential protection device comprising a differential lock according to the invention.

[0007] The invention will be better understood, thanks to the description below, which relates to several preferred embodiments, given by way of non-limiting examples, and explained with reference to the appended schematic drawings, in which: [ Fig. 1] Figure 1 represents a perspective view of a differential lock according to the invention and an electromagnetic relay for an electrical device for differential protection according to the invention in which the electromagnetic relay is in the closed position, the push button of the electromagnetic relay is in a retracted position and the differential lock trigger is in the armed position, [Fig. 2] Figure 2 represents a side view of the differential lock according to the invention and the electromagnetic relay for an electrical differential protection device according to the invention shown in Figure 1, [Fig. 3] Figure 3 represents a sectional and perspective view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the closed position, the first pair of contacts and the second pair of contacts are closed and the differential lock trigger is in the armed position, [Fig. 4] Figure 4 represents a sectional view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the closed position, the first pair of contacts and the second pair of contacts are closed and the trigger the differential lock is in the armed position, [Fig. 5] Figure 5 represents a perspective view of the differential lock according to the invention and the electromagnetic relay for an electrical device for differential protection according to the invention in which the electromagnetic relay is in the open position, the push button of the relay electromagnetic is in an extended position and the differential lock trigger is in the triggered position, [Fig. 6] Figure 6 represents a side view of the differential lock according to the invention and the electromagnetic relay for an electrical differential protection device according to the invention shown in Figure 5, [Fig. 7] Figure 7 represents a sectional and perspective view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the open position, the first pair of contacts and the second pair of contacts are closed and the differential lock trigger is in the triggered position following the detection of a differential fault, [Fig. 8] Figure 8 represents a sectional view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the open position, the first pair of contacts and the second pair of contacts are closed and the trigger of the differential lock is in the triggered position following the detection of a differential fault, [Fig. 9] Figure 9 represents a perspective view of the differential lock according to the invention and the electromagnetic relay for an electrical device for differential protection according to the invention in which the electromagnetic relay is in the closed position, the push button of the electromagnetic relay is in a retracted position under the effect of the means for resetting the differential lock and the trigger of the differential lock is in the pre-armed position, [Fig. 10] Figure 10 shows a side view of the differential lock according to the invention and the electromagnetic relay for an electrical differential protection device according to the invention shown in Figure 9, [Fig. 11] Figure 11 represents a sectional and perspective view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the closed position, the first pair of contacts and the second pair of contacts are open and the differential lock trigger is in the pre-armed position, and [Fig. 12] Figure 12 represents a sectional view of the electrical differential protection device according to the invention in which the electromagnetic relay is in the closed position, the first pair of contacts and the second pair of contacts are open and the trigger the differential lock is in the pre-armed position.

The invention relates to a differential lock 1 for an electrical differential protection device 2.

[0009] As illustrated in Figures 3, 4, 7, 8, 11 and 12, said electrical differential protection device 2 comprises at least: – a first current line comprising at least a first pair of contacts comprising a first contact movable and a first fixed contact, - a second current line comprising at least a second pair of contacts comprising a second movable contact C2 and a second fixed contact, - a switching lock 3 arranged to switch said first pair of contacts and said second pair of contacts, – an electromagnetic relay 4 comprising a push button 5, the electromagnetic relay 4 being configured to be closed in the absence of a differential fault in a closing position in which the push button 5 is in a retracted position PR and to be opened in the event of a differential fault in an opening position in which the push button 5 is in a PS output position, so as to trigger a trigger 6 of said differential lock 1.

The differential lock 1 comprises at least: - a trigger 6 for triggering in a triggered position PD said switching lock 3 of the electrical differential protection device 2 in the event of a differential fault, said trigger 6 being movable between a position armed PA in which said trigger 6 is arranged to be at a distance from the switching lock 3 and the triggered position PD in which said trigger 6 activates the switching lock 3.

[0011] According to the invention, said differential lock 1 is characterized in that: said trigger 6 is capable and intended to be moved from the triggered position PD to the armed position PA under the effect of the movement of the first movable contact in the event of opening of said first pair of contacts and said second pair of contacts, said differential lock 1 comprises reset means 8 capable and intended to be moved under the effect of the movement of the second movable contact C2 in the event of opening of said first pair of contacts and said second pair of contacts and being configured to move the push button 5 of the electromagnetic relay 4 from the output position PS to the retracted position PR in the event of opening of said first pair of contacts and said second pair of contacts.

[0012] Advantageously, the differential lock 1 according to the invention advantageously makes it possible to re-engage the trigger 6 in the event of opening of said first pair of contacts and said second pair of contacts following the detection of a differential fault . Indeed in this case, the trigger 6 is moved from the triggered position PD (Figures 5 to 8) towards the armed position PA, preferably passing through an intermediate position called pre-armed (Figures 9 to 12) under the effect of the movement of the first movable contact (not shown) during the opening of said first pair of contacts and said second pair of contacts. In the armed position (Figures 1 to 4), the trigger 6 is configured not to activate the switching lock 3, in particular being at a distance from it. In the triggered position (Figures 5 to 8), the trigger 6 is configured to actuate the switching lock 3 by being in particular in mechanical connection with it. Indeed, when releasing the trigger 6, it will preferably pivot and come into contact with another trigger of the switching lock 3. Preferably the trigger 6, under the action of a second torsion spring 21 described below, will in turn rotate the other trigger of the switching lock 3 and thus cause the opening of the first and second pairs of contacts. More advantageously, the differential lock 1 according to the invention makes it possible to reset the electromagnetic relay 4 of the electrical differential protection device 2 integrating such a differential lock 1, in the event of opening of said first pair of contacts and said second pair of contacts following the detection of a differential fault. Indeed and as illustrated in Figures 5 to 12, said differential lock 1 comprises reset means 8 of the electromagnetic relay 4 which are moved under the effect of the movement of the second movable contact C2 during the opening of said first pair of contacts and said second pair of contacts. These rearming means 8 make it possible more particularly to move the push button 5 of the electromagnetic relay 4 from the output position PS (Figures 5 to 8) towards the retracted position PR (Figures 9 to 12) when opening said first pair of contacts and said second pair of contacts. As a result, the energy coming from the opening of said first pair of contacts and said second pair of contacts of the electrical differential protection device 2 according to the invention makes it possible both to reengage the differential lock 1 and to reset the electromagnetic relay 4. In other words, the differential lock 1 according to the invention is configured to reset the electromagnetic relay 4 and to be reset thanks to the energy coming from the opening of said first pair of contacts and said second pair of contacts of the electrical differential protection device 2.

The first current line of the electrical differential protection device 2 which comprises the first pair of contacts is preferably a neutral current line. The second current line of the electrical differential protection device 2 which comprises the second pair of contacts is preferably a phase current line. This example is not limiting, the opposite is also possible.

Preferably, said differential lock 1 comprises locking means 7 configured to, in a locked position PV, immobilize the trigger 6 in the armed position PA (Figures 1 to 4) and in an unlocked position PDV (Figures 5 to 8) , release the trigger 6 to allow it to move from the armed position PA to the triggered position PD. The locking means 7 are capable and intended to be moved from the locked position PV to the unlocked position PDV under the effect of the movement of said push button 5 of the electromagnetic relay 4 from the retracted position PR to the output position PS.

Advantageously, as illustrated in Figures 1 to 4, in the locked position PV, the locking means 7 make it possible to freeze the position of the trigger 6 in the armed position PA. As illustrated in Figures 5 to 8, in the unlocked position PDV, the locking means 7 do not make it possible to freeze the position of the trigger 6 in the armed position PA, the latter can thus freely move towards the triggered position PD.

[0016] In this case, preferably said reset means 8 are capable and intended to move the locking means 7 from the locked position PV to the unlocked position PDV under the effect of the movement of the push button 5 of the electromagnetic relay 4 of the retracted position PR to the extended position PS.

[0017] Advantageously and as illustrated in Figures 1 to 8, the reset means 8 are configured to be moved by the push button 5 when it passes from the retracted position PR to the extended position PS to cause the movement of the means locking 7 from the locked position PV (figures 1 to 4) to the unlocked position PDV (figures 5 to 8).

[0018] Preferably and as illustrated in Figures 1 to 4, the locking means 7 comprise a pawl comprising a hook 9 arranged to engage in a locking portion 10 of complementary shape which the trigger 6 comprises in the PV locked position of the locking means 7.

Advantageously, in the armed position PA of the trigger 6 and in the locked position PV of the locking means 7, illustrated in Figures 1 to 4, the hook 9 of the pawl and the locking portion 10 cooperate to prevent movement of the trigger 6. On the contrary and as illustrated in Figures 5 to 8, in the triggered position PD of the trigger 6 and in the unlocked position PDV of the locking means 7, the hook 9 of the pawl and the locking portion 10 are disengaged and do not cooperate more, so as to authorize the movement of the trigger 6.

[0020] Preferably and as illustrated in the figures, the reset means 8 comprise a reset cam 11 comprising an actuation portion 12 capable and intended to be arranged substantially opposite said push button 5 and to be struck by the push button 5 of the electromagnetic relay 4 when moving from the retracted position PR (figures 1 to 4) to the output position PS (figures 5 to 8).

[0021] Advantageously, and as illustrated in Figures 1 to 8, the reset cam 11 interacts with the push button 5 and moves under the effect of the movement of the push button 5 from the retracted position PR to the extended position PS .

[0022] Preferably, the pawl comprises an actuation arm 13 located substantially opposite the actuation portion 12 and the actuation portion 12 is configured to actuate the actuation arm 13 to disengage the hook 9 from the locking portion 10 when moving from the locked position PV (Figures 1 to 4) to the unlocked position PDV (Figures 5 to 8) of the locking means 7.

[0023] Advantageously and as illustrated in Figures 1 to 8, the reset cam 11 can also actuate the actuating arm 13 of the pawl using the actuation portion 12 to move the locking means 7 from the locked position PV to the unlocked position PDV following the movement of push button 5 from the retracted position PR to the extended position PS and thus authorize the movement of trigger 6.

[0024] Preferably and as illustrated in the figures, the reset means 8 comprise a deformable member 14 mechanically connected to the reset cam 11 and said deformable member 14 is capable and intended to be actuated by a projecting element of the contact holder 15 of the second movable contact C2 in the event of opening of said first pair of contacts and said second pair of contacts so as to cause the movement of the actuation portion 12 to move the push button 5 of the electromagnetic relay 4 from the output position PS (figures 5 to 8) towards the retracted position PR (figures 9 to 12).

Advantageously, as illustrated in particular in Figures 9 to 12, the reset means 8 are provided with a deformable member 14 which can be actuated by a projecting element of the contact holder 15 in the event of opening of said first pair of contacts and said second pair of contacts. This deformable member 14 makes it possible to cause the movement of the reset cam 11 and more particularly of the actuation portion 12 to move the push button 5 of the electromagnetic relay 4 from the output position PS to the retracted position PR and thus reset the electromagnetic relay 4.

Preferably, said deformable member 14 comprises at least one flexible blade, preferably made of steel.

[0027] Preferably and as illustrated in Figures 1, 5 and 9, the differential lock 1 comprises a wall 16 on which the pawl is pivotally mounted by a first pivot connection 17, on which the reset cam 11 is pivotally mounted by a second pivot link 18 and on which the trigger 6 is pivotally mounted by a third pivot link 19.

This design has the advantage of providing a differential lock 1 according to the invention adopting the form of a subassembly which is particularly compact.

Furthermore, the wall 16 can also carry the electromagnetic relay 4.

Advantageously, the pawl can pivot thanks to the first pivot link 17.

The reset cam 11 can pivot thanks to the second pivot link 18.

The trigger 6 can pivot thanks to the third pivot link 19.

Preferably, the differential lock 1 comprises a first torsion spring 20 mounted around the first pivot link 17 and a second torsion spring 21 mounted around the third pivot link 19.

Advantageously, the first torsion spring 20 makes it possible to exert a torque on the locking means 7 in the locked position PV and to allow the automatic return of the locking means 7 from the unlocked position PDV to the locked position PV.

[0035] Advantageously, the second torsion spring 21 makes it possible to exert a torque on the trigger 6 in the armed position PA and to allow the automatic return of the trigger 6 from the pre-armed position PPA (Figures 9 to 12) towards the armed position PA (Figures 1 to 4), when the switching lock 3 is switched for example using the lever 22 and the first and second pairs of contacts are closed.

[0036] Preferably, the trigger 6 comprises a portion 23 which can be struck by a projecting element of the contact holder (not visible) of the first movable contact in the event of opening of said first pair of contacts and said second pair of contacts so as to cause the trigger 6 to move towards the pre-armed position PPA (Figures 9 to 12). In the pre-armed position, the trigger 6 is in an intermediate position between the armed position PA and the triggered position PD, in which the trigger 6 is actuated by the switching lock 3.

Preferably, the electromagnetic relay 4 of the electrical differential protection device 2 is monostable. The electromagnetic relay 4 preferably has a low impedance, for example between 46 and 76 Ohms.

The present differential lock 1 according to the invention is particularly suitable for an electrical differential protection device 2 of the voltage-independent differential circuit breaker type which integrates such an electromagnetic relay 4 with low impedance. Indeed, this type of electromagnetic relay 4 requires a differential lock 1 in the case where the electromagnetic relay 4 does not have sufficient energy to unlock the switching lock 3 of the electrical differential protection device 2.

[0039] The invention also relates to an electrical differential protection device 2, preferably a differential circuit breaker, said electrical differential protection device 2 comprising at least – a first current line comprising at least a first pair of contacts comprising a first movable contact and a first fixed contact, – a second current line comprising at least a second pair of contacts comprising a second movable contact C2 and a second fixed contact, – a switching lock 3 arranged to switch said first pair of contacts and said second pair of contacts, – an electromagnetic relay 4 comprising a push button 5, the electromagnetic relay 4 being configured to be closed in the absence of a differential fault in a closing position in which the push button 5 is in a retracted position PR and to be open in the event of a differential fault in an opening position in which the push button 5 is in a PS output position, so as to trigger a trigger 6 of said differential lock 1.

[0040] In accordance with the invention, the electrical differential protection device 2 is characterized in that it comprises a differential lock 1 according to the invention and as described previously.

Preferably, said electrical differential protection device 2 is in modular format. Said electrical differential protection device 2 is preferably contained in a modular housing of width equal to one module, or preferably equal to 18 millimeters.

Preferably, said electrical differential protection device 2 is a differential circuit breaker.

The differential circuit breaker is for example independent of the network voltage or the power source.

As illustrated in Figures 3, 4, 7, 8, 11 and 12, the differential lock 1 according to the invention is preferably positioned relative to the switching lock 3 in the immediate vicinity of the latter, for example next to it.

The electromagnetic relay 4, the differential lock 1 and the switching lock 3 are substantially aligned in a longitudinal direction X of the electrical differential protection device 2.

Figures 1 to 4 illustrate the differential lock 1 in the armed position, that is to say with the trigger 6 in the armed position PA, to which a torque is applied via the second torsion spring 21, and which is retained by the pawl of the locking means 7 in the PV locked position.

As illustrated in Figures 5 to 8, if a differential fault is present, the electromagnetic relay 4 will open causing the push button 5 to come out in the PS output position, for example over a stroke of 1.5 millimeters. The push button 5 will come into contact with the reset cam 11 of the reset means 8, then the reset cam 11 will rotate the pawl of the locking means 7 so as to pass them into the unlocked position PDV under the effort of the push button 5. The pawl of the locking means 7 will rotate until the balance between the latter and the trigger 6 is broken. The trigger 6 will then pivot to the triggered position PD and come into contact with the switching lock 3. The latter, under the action of the trigger 6, will in turn unlock and the first and second pairs of contacts will start to open.

As illustrated in Figures 9 to 12, when the first and second pairs of contacts open, the first and second movable contacts will respectively activate the trigger 6 and the reset cam 11 of the reset means 8. The energy coming from the springs of the first and second pairs of contacts and the spring of the contact holders 15 will make it possible to generate a movement of the trigger 6 and the reset cam 11. More precisely, the movement of the first movable contact will rotate the trigger 6 until it returns to the hooking position or pre-armed position PPA, that is to say that its position will allow the pawl to be positioned so as to retain the trigger 6. The movement of the second movable contact C2 will rotate the reset cam 11 via the deformable member 14 and thus bring in the push button 5 of the electromagnetic relay 4 until the latter closes. The deformation of the deformable member 14 will ensure that the push button 5 is always pushed back to its starting position, that is to say the retracted position PR and also to limit the force seen by the push button 5 and therefore by the different parts of the electromagnetic relay 4 in order to extend its lifespan.

The switching lock 3 of the electrical differential protection device 2 will then continue its opening movements of the first and second pairs of contacts and the lever 24 will return to the OFF position. As long as the first and second pairs of contacts are open and therefore the electrical differential protection device 2 is in the OFF position, the first movable contact and the second movable contact C2 will continue to exert a force respectively on the trigger 6 and the reset cam 11. This state of position of the parts will make it possible to maintain a constant and controlled effort on the push button 5 of the electromagnetic relay 4 in order to guarantee that the latter remains in the closed position. The lifespan of the electromagnetic relay 4 will thus be increased because its polar surfaces will be protected from any possible pollution or oxidation.

[0050] When the electrical differential protection device 2 is reset to the ON position, the first and second pairs of contacts will close and release the parts of the differential lock 1 to allow it to trigger the electrical device. differential protection 2 if a new leakage current fault appears.

[0051] Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims (12)

1. Differential lock (1) for an electrical differential protection device (2), said electrical differential protection device (2) comprising at least: – a first current line comprising at least a first pair of contacts comprising a first movable contact and a first fixed contact, – a second current line comprising at least a second pair of contacts comprising a second movable contact (C2) and a second fixed contact, – a switching lock (3) arranged to switch said first pair of contacts and said second pair of contacts, – an electromagnetic relay (4) comprising a push button (5), the electromagnetic relay (4) being configured to be closed in the absence of a differential fault in a closing position in which the push button (5) is in a position retracted (PR) and to be opened in the event of a differential fault in an opening position in which the push button (5) is in an extended position (PS), so as to trigger a trigger (6) of said differential lock ( 1), the differential lock (1) comprising at least: – a trigger (6) for triggering in a triggered position (PD) said switching lock (3) of the electrical differential protection device (2) in the event of a differential fault, said trigger (6) being movable between an armed position (PA) in which said trigger (6) is arranged to be at a distance from the switching lock (3) and the triggered position (PD) in which said trigger (6) activates the switching lock (3), said differential lock (1) is characterized in that: said trigger (6) is capable and intended to be moved from the triggered position (PD) to the armed position (PA) under the effect of the movement of the first movable contact in the event of opening of said first pair of contacts and said second pair of contacts, said differential lock (1) comprises reset means (8) capable and intended to be moved under the effect of the movement of the second movable contact (C2) in the event of opening of said first pair of contacts and said second pair of contacts and being configured to move the push button (5) of the electromagnetic relay (4) from the extended position (PS) to the retracted position (PR) in the event of opening of said first pair of contacts and said second pair of contacts . 2. Differential lock according to claim 1, characterized in that said differential lock (1) comprises locking means (7) configured to, in a locked position (PV), immobilize the trigger (6) in the armed position PA and in a unlocked position PDV, release the trigger (6) to allow it to move from the armed position (PA) to the triggered position (PD), the locking means (7) being capable and intended to be moved from the locked position (PV) to the unlocked position (PDV) under the effect of moving said push button (5) of the electromagnetic relay (4) from the retracted position (PR) to the extended position (PS). 3. Differential lock according to claim 2, characterized in that said reset means (8) are capable and intended to move the locking means (7) from the locked position (PV) to the unlocked position (PDV) under the effect of moving the push button (5) of the electromagnetic relay (4) from the retracted position (PR) to the extended position (PS). 4. Differential lock according to any one of claims 2 to 3, characterized in that the locking means (7) comprise a pawl comprising a hook (9) arranged to engage in a locking portion (10) of complementary shape that includes the trigger (6) in the locked position (PV) of the locking means (7). 5. Differential lock according to any one of claims 1 to 4, characterized in that the reset means (8) comprise a reset cam (11) comprising an actuation portion (12) capable and intended to be arranged substantially opposite said push button (5) and to be impacted by the push button (5) of the electromagnetic relay (4) when passing from the retracted position (PR) to the extended position (PS). 6. Differential lock according to claims 3, 4 and 5, characterized in that the pawl comprises an actuating arm (13) located substantially opposite the actuation portion (12) and in that the actuation portion (12) is configured to actuate the actuating arm (13) to disengage the hook (9) from the locking portion (10) when moving from the locked position (PV) to the unlocked position (PDV) of the means of lock (7). 7. Differential lock according to any one of claims 5 to 6, characterized in that the reset means (8) comprise a deformable member (14) mechanically connected to the reset cam (11) and in that said deformable member (14) is capable and intended to be actuated by a projecting element of the contact holder (15) of the second movable contact (C2) in the event of opening of said first pair of contacts and said second pair of contacts so as to drive the movement of the actuation portion (12) to move the push button (5) of the electromagnetic relay (4) from the extended position (PS) to the retracted position (PR). 8. Differential lock according to claim 7 characterized in that said deformable member (14) comprises at least one flexible blade, preferably made of steel. 9. Differential lock according to any one of claims 5 to 8, characterized in that it comprises a wall (16) on which the pawl is pivotally mounted by a first pivot connection (17), on which the reset cam ( 11) is pivotally mounted by a second pivot link (18) and on which the trigger (6) is pivotally mounted by a third pivot link (19). 10. Differential lock according to any one of claims 5 to 9, characterized in that it comprises a first torsion spring (20) mounted around the first pivot connection (17) and a second torsion spring (21) mounted around the third pivot link (19). 11. Electrical differential protection device (2) preferably a differential circuit breaker, said electrical differential protection device (2) comprising at least – a first current line comprising at least a first pair of contacts comprising a first movable contact and a first fixed contact, – a second current line comprising at least a second pair of contacts comprising a second movable contact (C2) and a second fixed contact, – a switching lock (3) arranged to switch said first pair of contacts and said second pair of contacts, – an electromagnetic relay (4) comprising a push button (5), the electromagnetic relay (4) being configured to be closed in the absence of a differential fault in a closing position in which the push button (5) is in a position retracted (PR) and to be opened in the event of a differential fault in an opening position in which the push button (5) is in an extended position (PS), so as to trigger a trigger (6) of said differential lock ( 1), said electrical differential protection device (2) comprising a differential lock (1) according to any one of claims 1 to 10. 12. Electrical differential protection device (2) according to claim 11, characterized in that said electrical differential protection device (2) is in modular format.