Polarized highly sensitive electromagnetic trip device for an electrical protection device and associated electrical protection device

Abstract

The invention relates to an electromagnetic trigger comprising a coil (1), an armature (2), comprising a single piece of armature (3) having a first polar face (4) and a second polar face (5) and having a U shape, a magnet (8), a movable paddle (9) mounted pivotally relative to the single piece of armature (3) at the level of a pivot joint (10) around a pivot point, a return element (11) having a first end (12) coupled to the armature (2) and a second end (13) coupled to the movable paddle (9), characterized in that the pivot joint (10) made of non-magnetic material is fixed to the first arm (6) of the single piece of armature (3) and is offset relative to the first arm (6) so that the pivot point is at a distance from the first and second polar faces (4, 5).

Description

[0001] The invention relates to the field of polarized high sensitivity electromagnetic trip units for electrical protection equipment and the field of electrical protection equipment fitted with such polarized high sensitivity electromagnetic trip units, in particular of the differential protection type.

[0002] The electromagnetic trip unit, also commonly called a relay, is an essential component of the differential function. It connects the electronic circuit of the differential function, which, along with a measuring toroid, detects differential faults, to the mechanical part consisting of the mechanical lock and the electrical contacts that enable the breaking. An electromagnetic trip unit typically consists of a magnetic circuit, most often in two parts: a fixed part and a moving part, a permanent magnet, a spring, and a coil that can be powered by an external electronic circuit.The choice of magnetic structure for the electromagnetic trip unit must meet very stringent specifications, requiring compact dimensions to optimize its integration into electrical protection equipment, electrical characteristics enabling robust and compact differential functions, immunity to electromagnetic and climatic environments, and mechanical stability. To allow for cost-competitive industrialization, the electromagnetic trip unit's structure must also optimize the use of high-grade magnetic materials and reduce the number of assembly steps.

[0003] The current transformer, the electronic circuit, and the high-sensitivity polarized electromagnetic trip unit are typically sized to meet regulatory specifications related to personal protection and also to comply with volumetric constraints in order to be integrated into the increasingly compact platforms of electrical protective equipment. The key to this compactness lies particularly in the size of the electromagnetic trip unit, its power output, and its stability. Indeed, an electromagnetic trip unit that provides stable activation at a low power level allows the use of a small current transformer.

[0004] Saturated shunt-type electromagnetic trip units are known for use in protective devices, preferably differential ones. A saturated shunt-type electromagnetic trip unit comprises a coil and an armature, preferably made of magnetic material. The armature is a single piece with a first pole face and a second pole face, and is U-shaped. A first arm has the first pole face, and a second arm has the second pole face. The second arm is surrounded by the coil. A magnet is attached to the armature, most often at a junction between the first and second arms. A movable paddle is pivotally mounted relative to the single armature piece at a pivot joint around a pivot point located on the first pole face. The electromagnetic trip unit also includes a return element coupled to the movable paddle.

[0005] This type of saturated shunt electromagnetic trigger offers the advantage of a very simple magnetic structure with a single armature. This results in simplified manufacturing and satisfactory robustness. However, it has the disadvantage of being rather bulky.

[0006] Document EP0829896A2 describes a magnetic trip unit for a residual current circuit breaker, comprising a magnetic circuit powered by a permanent magnet with a U-shaped armature and a pivoting pivoting armature at a pivoting edge, and a spring element designed to actuate the pivoting armature in the opposite direction to a force generated by the permanent magnet. This solution is particularly noteworthy because the spring element is a torsion spring with its winding axis aligned with the pivoting edge. This solution offers the advantage of a highly effective hinge, but at the expense of compactness. The armature comprises two V-shaped armature plates, and the permanent magnet is formed as a prism.As a result, the volume of the magnet and the thickness of the electromagnetic trigger are higher compared to the solutions described previously.

[0007] This type of electromagnetic shunt air gap trigger has the disadvantage of offering a two-part armature which is complex to industrialize, particularly due to the management of the air gap between the two armature pieces.

[0008] The present invention aims to overcome at least one of these drawbacks and seeks to propose a new high-sensitivity electromagnetic trigger structure with a small volume compared to the prior art known which makes it possible to meet the compactness constraints.

[0009] For this purpose, the invention relates to an electromagnetic trigger according to claim 1.

[0010] The invention also relates to an electrical protection device according to claim 11.

[0011] The invention will be better understood from the following description, which relates to several preferred embodiments, given by way of non-limiting examples, and explained with reference to the accompanying schematic drawings, in which: [ Fig. 1 ] there figure 1 represents a perspective view of an electromagnetic trigger in a first embodiment according to the invention, [ Fig. 2 ] there figure 2 represents a perspective view of the electromagnetic trigger of the figure 1 , [ Fig. 3 ] there figure 3 represents a side view of the electromagnetic trigger of the figure 1 , [ Fig. 4 ] there figure 4 represents a top view of the electromagnetic trigger of the figure 1 , [ Fig. 5 ] there figure 5 represents a perspective view of an electromagnetic trigger in a second embodiment according to the invention, [ Fig. 6 ] there figure 6 represents a perspective view of the electromagnetic trigger of the figure 5 not showing the cylinder heads, [ Fig. 7 ] there figure 7 represents a side view of the electromagnetic trigger of the figure 6 , [ Fig. 8 ] there figure 8 represents a top view of the electromagnetic trigger of the figure 6 , And [ Fig. 9 ] there figure 9 represents a top view of the electromagnetic trigger of the figure 6 .

[0012] An electromagnetic trip unit for a protective device, preferably a differential one, comprises at least: a coil 1, an armature 2, preferably of magnetic material, comprising a single armature piece 3 having a first polar face 4 and a second polar face 5 and having a U shape with a first arm 6 having the first polar face 4 and a second arm 7 having the second polar face 5, the second arm 7 being surrounded by said coil 1, the first arm 6 and the second arm 7 extending longitudinally in a first direction D1, a magnet 8 associated with said armature 2, a movable pallet 9 mounted pivotally relative to the single armature piece 3 at a pivot joint 10 around a pivot point P, a return element 11 having a first end 12 coupled to the armature 2 and a second end 13 coupled to the movable pallet 9.

[0013] According to the invention, the electromagnetic trigger is characterized in that: The pivot joint 10 made of non-magnetic material is fixed to the first arm 6 of the single armature piece 3 and is offset from the first arm 6 so that the pivot point P is at a distance from the first and second polar faces 4, 5.

[0014] This configuration maximizes the use of magnetic forces in the air gaps between the first / second polar faces 4, 5 and the moving paddle 9 by separating the pivot joint 10 from the first polar face 4. This increases the distance between the first polar face 4 and the pivot point P, thereby increasing the torque proportionally to the lever arm. The size of the magnetic circuit can be reduced, and consequently, the electromagnetic trigger can be more compact. Furthermore, the pivot joint 10 is no longer subjected to a magnetic field because it is made of a harder, non-magnetic material that better withstands endurance tests. This results in improved robustness.Industrialization is further improved since the single armature piece 3 has the advantage of eliminating assembly operations, particularly welding, unlike a prior art electromagnetic trigger with an armature made of two pieces separated by an air gap and joined by welding. The addition of a non-magnetic pivot joint 10 or offset hinge on the structure with a single armature 2 with a saturated shunt allows the magnetic and mechanical functions to be decoupled. This makes it possible to use a non-magnetic material with very high hardness, such as Inconel NiCr, which is four times harder than FeNi (a magnetic material) and will make the electromagnetic trigger more wear-resistant.Furthermore, the addition of the pivot link 10 allows the pivot point to be shifted, increasing the lever arm and thus, at constant torque, reducing the attractive forces between the moving blade 9 and the armature 2 at the pole faces 4 and 5. This reduces the size of the magnetic circuit and therefore the overall volume of the relay. However, this also reduces the torque delta (the decrease in torque when coil 1 is energized) and therefore risks decreasing the stability of the electromagnetic trigger during shock and vibration (risk of opening). One solution to compensate for this drawback is to add yokes on either side of the magnet 8 to concentrate the magnetic flux generated by the magnet 8 and saturate the shunt very locally, as detailed below.The advantage is seen on the torque delta / torque of the structure which will allow going from 10-15% without cylinder heads to 20-25% with cylinder heads and thus increase the torque delta which will compensate for the decrease in stability induced by the use of an offset hinge.

[0015] Preferably, the single reinforcement piece 3 includes an additional portion of reinforcement 14 which extends the first arm 6 at least in a second direction D2 called horizontal and being perpendicular to the first direction D1 and opposite the second arm 7, the additional portion of reinforcement 14 supporting the pivot joint 10 and being disposed under the pivot point P.

[0016] Advantageously, the addition of the additional portion of reinforcement 14 by the extension of the first arm 6 makes it possible to move the pivot joint 10 and the pivot point P away from the first polar face 4, without having to add an additional part separate from the first arm 6. This results in a simplification of industrialization.

[0017] Preferably, the additional portion of the armature 14 is made of magnetic material and has a notch 15 into which the magnet 8 is inserted.

[0018] Advantageously, the additional armature section 14 allows the magnet 8 to be integrated into the single armature piece 3, which also allows the magnetic field of the magnet 8 to be diverted into the additional armature section 14. This improves compactness without complicating industrialization. Indeed, the notch 15 has the advantage of being easy to manufacture, for example, by a cutting operation or similar process. The single armature piece 3 has the advantage of eliminating the need for assembly operations, particularly welding. Finally, in this arrangement, the pivot point P is located above the magnet 8 and at a distance from the first polar face 4.

[0019] Preferably, the magnet 8 and the notch 15 extend longitudinally along the second direction D2 and the inlet 15a of the notch 15 is opposite the first and second arms 6, 7.

[0020] Advantageously, this arrangement facilitates the insertion of the magnet 8 and consequently the manufacture of the electromagnetic trigger.

[0021] Preferably, the notch 15 includes a longitudinal slot 16 extending longitudinally in the second direction D2 in which the magnet 8 is totally housed, the magnet 8 preferably having a parallelepiped shape, preferably rectangular, and the longitudinal slot 16 is extended by a through hole 17, preferably circular or triangular.

[0022] Preferably, the electromagnetic trigger further comprises a first breech and a second breech 19 resting respectively on the first external face and the second external face 21 of the additional portion of armature 14, which cover at least the magnet 8 inserted in the notch 15.

[0023] Advantageously, this arrangement improves performance, particularly the stability of the electromagnetic trigger. The difference in torque between the magnetic and the magnetic shunt in the configuration with the shunt can reach 20%, compared to 10% in the version without the shunt. Adding magnetic shunts on either side of magnet 8 directs the magnetic flux of magnet 8 into the saturated shunt, thus optimizing the magnetic circuit seen by coil 1. This increases the difference between the torque at zero current and the torque at the moment the relay is triggered. This parameter is commonly referred to as the difference between the torque at zero current and the torque at the moment the relay is triggered.

[0024] Preferably, the electromagnetic release includes at least one hinge support 22 mounted on the additional armature portion 14 and the hinge support 22 including a first coupling end 23 coupled to the first end 12 of the return element 11 and a second coupling end 24 coupled directly or indirectly to the movable pallet 9.

[0025] Advantageously, the additional reinforcement portion 14 also supports the hinge support 22 to which the return element 11 extending along the first direction D1 is coupled. Thus, the return element 11 can be coupled to the reinforcement 2.

[0026] The electromagnetic trigger preferably has a thickness between 7 and 9 millimeters.

[0027] Preferably, the return element 11 is arranged longitudinally along a first direction D1 called vertical substantially parallel to the first arm 6. The return element 11 can have a tolerance angle between 0 degrees and 10 degrees with respect to the first direction D1 in this case also the return element 11 is considered to extend along the first direction D1 called vertical, this angle being considered small.

[0028] Advantageously, the return element 11 extends along the first direction D1, called vertical, substantially parallel to the first arm 6, which allows the mobile pallet 9 to be pressed against the first and second polar faces 4, 5 of the frame 2 in the closed position while creating an opening torque for the mobile pallet 9.

[0029] The return element 11 is preferably a tension spring.

[0030] The reinforcement 2 consists of a single piece of reinforcement 3.

[0031] The single reinforcement piece 3 is preferably formed from at least one plate.

[0032] The single armature piece 3 has a U-shape with the first arm 6 and the second arm 7 which are joined by a connecting segment 25. The first arm 6 has the first polar face 4. The second arm 7 is surrounded by the coil 1 and has the second polar face 5.

[0033] The first polar face 4 and the second polar face 5 are preferentially coplanar.

[0034] Preferably, the magnet 8 is permanent and is made of a ferromagnetic material for example an AINiCo alloy, or ferrite.

[0035] Magnet 8 preferably has the shape of a rectangular parallelepiped or a truncated pyramid with a square or rectangular base (not shown) or cylindrical base (not shown) or prism (not shown).

[0036] The magnetization direction of magnet 8 can be: in the vertical direction, i.e. along the first direction D1, or in the vertical direction, i.e. in a direction perpendicular to the first and second directions D1, D2.

[0037] The mobile pallet 9 is mounted to pivot relative to the reinforcement 2 at the pivot joint 10 around a pivot point P. The pivot joint 10 is fixed to the first arm 6 of the single reinforcement piece 3, preferably via the additional reinforcement portion 14, and is offset relative to the first arm 6.

[0038] The pivot joint 10 preferably includes a third face 26 relative to which the movable pallet 9 pivots. The first polar face 4, second polar face 5, and third face 26 are preferably coplanar.

[0039] The pivot joint 10 is made of non-magnetic material, for example Inconel NiCr.

[0040] The pivot joint preferably has a parallelepiped shape.

[0041] The pivot joint 10 rests on an upper face 27 of the additional portion of reinforcement 14 and is aligned with the ends 28, 29 of the first and second arms 6, 7.

[0042] Preferably, in the untriggered position of the electromagnetic trigger, the movable paddle 9 is in contact with the first polar face 4, the second polar face 5 and the third face 26 so as to close the magnetic circuit comprising said armature 2 and the movable paddle 9. In the so-called triggered or open position illustrated in the figures, the movable paddle 9 is pivoted and is at a distance from the first polar face 5, and the second polar face 6.

[0043] The mobile pallet 9, for example, has the shape of a bar with a rectangular or square section, preferably straight.

[0044] As illustrated in the figures, the movable pallet 9 can be covered by a sheet 30 at its end resting on the third face 26. The movable pallet 9 is coupled indirectly or directly to the return element 11 preferably at this end.

[0045] As illustrated in the figures, the return element 11 is preferably coupled indirectly by the first end 11 to the frame 2 via the hinge support 22. The return element 11 is coupled directly by the second end 13 to the movable pallet 9 or the return element 11 is coupled indirectly by the second end 13 to the movable pallet 9 via the sheet 30. The return element 11 is arranged longitudinally along the first direction D1 which is said to be vertical.

[0046] As illustrated in the figures, the additional reinforcement portion 14 is part of the single reinforcement piece 3. The additional reinforcement portion 14 is preferably planar and formed within the plate of the single reinforcement piece 3. The additional reinforcement portion 14 is preferably in the same plane as the first arm 6. The additional reinforcement portion 14 forms an extension of the first arm 6 in this plane. The additional reinforcement portion 14 extends on the side opposite the second arm 7 lengthwise along the second direction D2 perpendicular to the first direction D1 and extends vertically along the first direction D1. The height h2 of the additional portion 14 is less than the height h1 of the first arm 6, such that the end 28 of the first arm 6, which bears the first polar face 4, protrudes beyond the upper face 27 of the additional portion 14.The pivot joint 10 has a height approximately equal to that of the end 28 of the first arm 6 which carries the first polar face 4.

[0047] As illustrated in the figures, the additional armature portion 14 preferably incorporates the magnet 8 in the notch 15. The additional armature portion 14 further comprises an end face 31 which is opposite the first and second arms 6, 7 and which includes the inlet 15a of the notch 15. The notch 15 extends longitudinally in the second direction D2 and has a length l2 greater than or equal to the length l1 of the additional armature portion 14. The notch 15 may extend into the first arm 6. The height h3 of the notch 15 extends along the first direction D1 and corresponds to a portion of the height h2 of the additional armature portion 14. The notch 15 is located approximately in the middle of the additional armature portion 14.

[0048] As illustrated in the figures, the notch 15 can be a longitudinal slot 16 substantially median and which has a shape complementary to that of the magnet 8.

[0049] As illustrated in the figures, the through hole 17 is preferably located on the additional portion of reinforcement 14 and on the first arm 6, and predominantly at the level of the additional portion of reinforcement 14.

[0050] The first and second breechblocks 19 are optional. The first and second breechblocks 19 preferably cover the magnet 8 inserted in the notch 15 and preferably the through hole 17.

[0051] The first cylinder head is preferably in the form of a flat plate.

[0052] The second breechblock 19 is preferably in the form of a flat plate.

[0053] Preferably, the armature 2, the first breechblock and second breechblock 19 and the movable pallet 9 are made of magnetic materials with high permeability, such as FeNi or iron.

[0054] The hinge support 22 is preferably fixed to the additional portion of the frame 14 at the end face 31

[0055] The hinge support 22 is preferably a plate with a U-shaped cutout forming the second coupling end 24 and a portion bent perpendicular to the plate or a hook forming the first coupling end 23.

[0056] THE figures 1 à 4 The diagram illustrates the electromagnetic trigger in the first embodiment according to the invention. It comprises the coil 1, the armature 2, made of magnetic material, in the form of the single armature piece 3, the movable paddle 9, the return element 11, and the pivot joint 10. The single armature piece 3 has the first polar face 4 and the second polar face 5 and is U-shaped, with the first arm 6 and the second arm 7 joined by the connecting segment 25. The second arm 6 is surrounded by said coil 1. The first arm 6 and the second arm 7 extend longitudinally along a first direction D1. The magnet 8 is integrated into the single armature piece 3.The pivot joint 10, made of non-magnetic material, is fixed to the first arm 6 of the single armature piece 3 via the additional armature portion 14, which is part of the single armature piece 3 and offset from the first arm 6 so that the pivot point P is at a distance from the first and second polar faces 4 and 5. In this first embodiment, the notch 15 is median and takes the form of the longitudinal slot 16, which terminates in the circular through hole 17 that overlaps the first arm 6. The magnet 8, which is inserted into the longitudinal slot 16, has the shape of a parallelepiped bar. The magnetization direction of the magnet 8 is vertical, i.e., along the first direction D1.

[0057] THE figures 5 à 9The diagram illustrates the electromagnetic trigger in the second embodiment according to the invention. In this second embodiment, the notch 15 is central and takes the form of the longitudinal slot 16, which terminates in the triangular through hole 17, with the apex of the triangle overlapping the first arm 6. The magnet 8, which is inserted into the longitudinal slot 16, is parallelepiped-shaped. Furthermore, the electromagnetic trigger is provided with the first and second breechblocks 19 in the form of flat plates that cover both the magnet 8 and the notch 15. The magnetization direction of the magnet 8 is along the depth, that is, in a direction perpendicular to the first and second directions D1, D2.

[0058] The invention also relates to an electrical protection device comprising an electromagnetic trigger, characterized in that the electromagnetic trigger is according to the invention.

[0059] Differential electrical equipment can be, for example, of the type of differential circuit breaker called RCBO, differential switch called RCCB, differential block called AOB.

[0060] Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

1. Electromagnetic trip unit for a protective device, preferably a differential one, comprising at least: - a coil (1), - an armature (2), preferably made of magnetic material, comprising a single armature piece (3) having a first polar face (4) and a second polar face (5) and having a U-shape with a first arm (6) comprising the first polar face (4) and a second arm (7) comprising the second polar face (5), the second arm (7) being surrounded by said coil (1), the first arm (6) and the second arm (7) extending longitudinally in a first direction (D1), - a magnet (8) associated with said armature (2), - a movable paddle (9) pivotally mounted relative to the single armature piece (3) at a pivot joint (10) about a pivot point (P), - a return element (11) having a first end (12) coupled to the armature (2) and a second end (13) coupled to the movable paddle (9),the electromagnetic trigger is, characterized in that - the pivot joint (10) in non-magnetic material is fixed to the first arm (6) of the single armature piece (3) and is offset from the first arm (6) so that the pivot point (P) is at a distance from the first and second polar faces (4, 5).

2. Electromagnetic trigger according to claim 1, characterized in that the single reinforcement piece (3) includes an additional portion of reinforcement (14) which extends the first arm (6) at least in a second direction (D2) called horizontal and being perpendicular to the first direction (D1) and opposite to the second arm (7), the additional portion of reinforcement (14) supporting the pivot joint (10) and being disposed under the pivot point (P).

3. Electromagnetic trigger according to claim 2, characterized in thatthe additional portion of armature (14) is made of magnetic material and has a notch (15) into which the magnet (8) is inserted.

4. Electromagnetic trigger according to any one of claims 2 to 3, characterized in that the magnet (8) and the notch (15) extend longitudinally along the second direction (D2) and in that the entry (15a) of the notch (15) is opposite the first and second arms (6, 7).

5. Electromagnetic trigger according to claims 3 and 4, characterized in that the notch (15) includes a longitudinal slot (16) extending longitudinally in the second direction (D2) in which the magnet (8) is fully housed, the magnet (8) preferably having the shape of a parallelepiped, preferably rectangular, and in that the longitudinal slot (16) is extended by a through hole (17) preferably circular or triangular.

6. Electromagnetic trigger according to claims 3 and 4 or according to claim 5, characterized in that it further comprises a first breech and a second breech (19) resting respectively on the first external face and the second external face (21) of the additional portion of armature (14), which cover at least the magnet (8) inserted in the notch (15).

7. Electromagnetic trigger according to any one of claims 2 to 5, characterized in that it includes at least one hinge support (22) mounted on the additional portion of the frame (14) and the hinge support (22) comprising a first coupling end (23) coupled to the first end (12) of the return element (11) and a second coupling end (24) coupled directly or indirectly to the movable pallet (9).

8. Electromagnetic trigger according to any one of claims 1 to 7, characterized in thatThe electromagnetic trigger has a thickness of between 7 and 9 millimeters.

9. Electromagnetic trigger according to any one of claims 1 to 8, characterized in that the return element (11) is arranged longitudinally along a first direction (D1) called vertical substantially parallel to the first arm (6).

10. Electromagnetic trigger according to any one of claims 1 to 9, characterized in that the return element (11) is a tension spring.

11. Electrical protective equipment comprising an electromagnetic trip unit, characterized in that the electromagnetic trigger is according to any one of claims 1 to 10.

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