Improved switchgear or contactor with high arc extinction capability

Abstract

The present invention relates to an improved switchgear or contactor device (1) with high arc extinction capability, particularly for industrial and railway applications where high currents must be switched on and off, said switchgear or contactor device (1) comprising in a housing (10): - a switch base portion (2) containing an electrical switchgear (35) of a low voltage drive portion (4) acting on moving contacts (21, 22); - a high voltage portion (5) containing said moving contacts (21, 22) driven towards and away from each other with respect to a mutual contact position, said moving contacts (21, 22) being mounted at respective contact ends of an elbow mechanism (30) movable by the low voltage drive portion (4), and - a top arc barrier extinction portion (3) covering said high voltage portion (5), wherein hardware means (40) are provided in the vicinity of said moving contacts (21, 22) to influence an arc (29) occurring when the moving contacts (21, 22) moving towards and away from each other switch on and off the current.

Description

Technical Field

[0001] The present invention relates to an improved switching device or contactor with high arc extinguishing capability, which is particularly suitable for industrial and railway applications.

[0002] More specifically, but not exclusively, the present invention relates to a contactor device for industrial and / or railway applications, such as those requiring high switching capability to connect and disconnect high DC currents to control electric motors, lighting, heating, capacitor banks, thermal evaporators, and other electrical loads. Background Technology

[0003] As is well known in this particular field of knowledge, a contactor is a remote control switch containing an electromagnetic actuator, which can be used in many industrial or railway applications where switching operations must be performed at a relatively high frequency to connect and disconnect high AC or DC currents.

[0004] Generally speaking, a contactor can be considered a switching device used in high-current and high-voltage applications, regardless of the electrical load being driven.

[0005] However, to illustrate the operating conditions of these types of contactors and the range of current values ​​involved, it should be noted that these devices must be able to effectively switch current in a range of at least 400A to 1800A and in an operating voltage range of 1000V to 4000V.

[0006] Those operating ranges even involve a single pole of the contactor, but in many applications, however, a two-pole or three-pole configuration must be provided.

[0007] A contactor of known structure typically comprises fixed contacts, movable contacts, and at least a contactor coil. In a normally open device, when sufficient starting current flows through the contactor coil, the contactor reacts and connects the load to the load circuit.

[0008] To maintain the contactor in this state, a holding current must flow continuously through it. Once the holding current is disconnected, the contactor disengages. The energy stored in the contactor coil is dissipated in the freewheeling circuit, or better yet, in a fast and appropriate overvoltage protection device (such as Varistor or Transil).

[0009] High-quality and high-performance contactors require an arc-extinguishing section, also known as an arc-damping section, to properly extinguish any arcs that may be generated in the high-voltage section of the switch where movable contacts are located.

[0010] One of the main problems encountered in the manufacture of switching devices for high-current and high-voltage applications is the correct dimensional accuracy of the arc-extinguishing section.

[0011] This design phase is particularly critical because sometimes it is necessary to expand and extend the arc barrier section according to the version of the switchgear; in other words, according to the operating current or voltage that the switchgear must manage.

[0012] Furthermore, when contactors are used in low-current applications, the arc extinction phase is a practical problem.

[0013] In practice, contactors are typically designed to switch high currents, and when the switching current is below a predetermined threshold (e.g., only a few amperes), the magnetic field generated in the arc-blowing coil is insufficient to cause the arc to circulate around the arc-extinguishing chamber. Such a current, insufficient to cause the arc to circulate around the arc-extinguishing chamber, is defined as a "low (switching) current." This current is also known as the "critical current."

[0014] The technical problem upon which this invention is based is to provide an improved switching device or contactor for high-current or high-voltage switching applications, the improved switching device or contactor having structural and functional features to allow for more effective dissipation of arcs that may be generated during the opening or closing phase of movable contacts, thereby giving the device a higher arc-extinguishing capability.

[0015] Another object of the present invention is to provide a switching device that has higher reliability and longer service life due to its higher efficiency during the possible arc breaking phase.

[0016] Another object of the present invention is to provide a switching device that can be made of materials with reasonable industrial costs. Summary of the Invention

[0017] The solution based on the present invention is to provide a hardware device that can extinguish the electric arc when the contactor switch is at a low current.

[0018] These hardware devices preferably include magnetic elements positioned near the moving contacts of the contactor to generate a magnetic field sufficient to at least partially circumvent and extinguish arcs generated when low switching currents are involved. Advantageously, those magnetic elements are permanent magnets.

[0019] Based on the above-described solution and according to one aspect of the invention, the technical problem is solved by an improved switching device or contactor, which has high arc-extinguishing capability and includes, within a protective housing:

[0020] - A switch base portion, the switch base portion comprising an electrical switching device that acts on a low-voltage drive portion of a moving contact;

[0021] - A high-voltage section comprising movable contacts driven relative to each other and away from each other at mutually contacting positions, the movable contacts being mounted at corresponding contact ends of the elbow mechanism, the elbow mechanism being movable by a low-voltage drive section; and

[0022] - The top arc extinguishing section covering the high-voltage portion.

[0023] Its features include:

[0024] A hardware device disposed near the moving contacts to influence the arc that occurs when the moving contacts move toward and away from each other to make or break current.

[0025] Advantageously, the hardware device includes a magnetic element positioned close to the moving contact to generate a magnetic field sufficient to at least partially circumvent the arc when low switching currents are involved.

[0026] More specifically, advantageously, the magnetic element is a permanent magnet.

[0027] Furthermore, advantageously, the magnetic element is positioned at each lateral side of each moving contact.

[0028] It should be noted that each of the magnetic elements is advantageously configured as a disk, which is supported in a fixed position on the side of the corresponding moving contact when the moving contact is in the rest or open position.

[0029] Advantageously, the contactor of the present invention comprises at least four magnetic elements, two for each moving contact.

[0030] It should be understood that, advantageously, the hardware device functions to orient the electric arc toward the top arc partition, and the hardware device primarily functions when the low current flowing through the arc-blowing coil is insufficient to generate a suitable electromagnetic force.

[0031] Advantageously, the arc flow channel is disposed above each corresponding moving contact in the open or stopped position of each corresponding moving contact, and the hardware device including the magnetic element is positioned on both sides of each arc flow channel.

[0032] Each arc flow channel is advantageously formed of a flat metal plate extending above a corresponding moving contact and curved laterally on both sides to have opposing flanges, the opposing flanges partially and laterally protecting the corresponding moving contact; the magnetic element is positioned on both sides of the opposing flanges.

[0033] Further features and advantages of the switching or contactor device of the present invention will become apparent from the following description, given by way of non-limiting example with reference to the accompanying drawings. Attached Figure Description

[0034] - Figure 1 A perspective view of a switching device or contactor implemented according to the present invention is shown;

[0035] - Figure 2 Show Figure 1 A front view of a switching device or contactor device, wherein the side cover has been removed;

[0036] - Figure 3 Show Figure 1 A three-dimensional schematic diagram of the switching device, in which the side cover has been removed;

[0037] - Figure 4 Show Figure 2 and 3 A front enlarged schematic diagram of the upper center part of the contactor device;

[0038] - Figure 5 A top view schematic diagram of a single-pole contactor according to the present invention is shown, wherein the arc diaphragm portion is removed and the upper arc extinguishing portion is visible;

[0039] - Figure 6 Show Figure 5 A side view of the movable contacts of the contactor portion, viewed from the center point of the contactor; and

[0040] - Figure 7 A perspective view of different arc partition portions according to the present invention is shown. Detailed Implementation

[0041] Referring to the accompanying drawings, a switching device or contactor device implemented according to the present invention is shown generally and schematically by reference numeral 1.

[0042] Specifically, but not exclusively, contactor 1 is specifically configured for industrial or rail applications, such as those requiring high-frequency switching operations to connect and disconnect high DC currents to control electric motors, lighting, heating, capacitor banks, thermal evaporators, and other electrical loads.

[0043] To illustrate the operating conditions and current ranges involved for these types of contactors, it should be noted that these devices must be able to effectively switch currents ranging from at least 400A to 1800A and operating voltages between 1000V and 4000V. For example, the LTX series line contactors are constructed to operate at high rated voltages, high thermal currents, and where high breaking capacity (up to 4kV) is required.

[0044] These operating ranges can even extend to a single pole of the contactor. However, in many applications, although not shown in the accompanying drawings, bipolar and / or tripolar configurations must be provided, which can be achieved by connecting multiple single poles side by side due to the modular single-pole structure.

[0045] In the following text, we will only disclose the structure of the single-pole module, because the same principle can be used on each pair of moving contacts even when installed in a double-pole or triple-pole contactor.

[0046] The module has a housing or enclosure 10 that protects and covers all moving parts of the contactor device 1. The housing 10 is made of a synthetic plastic material having a predetermined isolation factor and a high tracking index (CTI). Such a housing 10 has a bottom flange 13 and contains an internal frame 20 that supports the various moving parts of the contactor 1.

[0047] It should be noted that fixed terminal power contacts 11 and 12 are provided for contactor 1. These fixed contacts 11 and 12 protrude from opposite lateral sides of housing 10; however, other arrangements may be used.

[0048] The terminal power contacts 11, 12 are respectively associated with corresponding internal moving contacts 21, 22 disposed inside the contactor device 1, as will be explained below. Advantageously, the creepage distance and clearance distance between the moving contacts 21 and 22 have been broadly sized for safe applications in polluted environments, but the narrow profile of the housing 10 is particularly conceived for applications where space is a critical issue.

[0049] The contactor 1 of the present invention is configured for use in electrical equipment that operates under conditions of severe shocks and vibrations typically occurring on the vehicle body of a traction vehicle. However, nothing prevents the use of this contactor 1 in all applications where high AC or DC currents must be switched on and off, such as line contactors, power switches or converters, traction motors, electromagnetic brakes, and heating / air conditioning systems.

[0050] Contactor 1 includes a switch base portion 2 and an upper arc-extinguishing portion 3. The innovative design of this invention (LTX circuit) combines traditional arc diaphragm (ceramic fin) technology with a new arc-extinguishing system. The ceramic arc diaphragm can withstand the highest rated current, and the new arc-extinguishing system ensures high reliability at critical currents.

[0051] The switch base portion 2 is common to each different modular contactor 1 and corresponds to the main structure of the housing 10, while the upper arc-extinguishing portion 3 can be considered as the top cover of the housing 10, which may have different dimensions depending on the different power categories and voltage ranges that the contactor should provide. The switch base portion 2 contains an electrical switching device 35.

[0052] like Figure 7 As shown, the upper arc-extinguishing section 3 can be structurally different depending on the different voltage ranges that must be handled and the corresponding arc diaphragm type and energy capacity that should be completely and safely extinguished.

[0053] The arc-extinguishing section 3 for a voltage value of 1000V can have Figure 1 , 2 The structure shown in Figure 3 may be used, but for higher voltage values ​​up to 3000V, the arc extinguishing section may require a larger or thicker extinguishing section and a larger polarity extension.

[0054] According to the present invention, a hardware device 40 is provided in the switch base portion 2 of the contactor 1 for attracting an electric arc when the contactor 1 switches at a relatively low current. Figure 4 , 5 And in Figure 6, such an electric arc is schematically shown with reference numeral 29.

[0055] These hardware devices 40 include magnetic elements 41, 42 positioned near the moving contacts 21, 22 of the contactor 1 to generate a magnetic field 18 sufficient to partially circumvent and extinguish such an arc 29, particularly when low switching currents are involved.

[0056] Advantageously, those magnetic elements 41 and 42 are permanent magnets.

[0057] Moreover, the magnetic elements 41, 42 are positioned at each lateral side of each moving contact 21, 22.

[0058] It should be noted that each of the magnetic elements 41 and 42 is configured as a disk, and when the moving contacts 21 and 22 are in the stopped or open position, the disk is supported in a fixed position on the side of the corresponding moving contacts 21 and 22.

[0059] The illustrated embodiment of contactor 1 includes at least four magnetic elements 41, 42, and two moving contacts 21, 22.

[0060] It should be understood that the hardware device functions to direct the electric arc toward the top arc barrier, and the hardware device primarily functions when the low current flows through the main contact.

[0061] These magnetic elements 41, 42 are in an inclined position that is substantially perpendicular to the corresponding moving contacts 21, 22 and supported in the housing 10 at a predetermined distance of a few millimeters from the arc channels 23, 24.

[0062] exist Figure 2 The diagram shows the internal schematic structure of the switch base portion 2, which includes the electrical switching device 35.

[0063] Conceptually, the switching part 2 can be considered as being divided into a low-voltage part 4 and a high-voltage part 5 located above the low-voltage part 4. The low-voltage part 4 is configured as a switch for driving the movement of contacts 21 and 22 inside the upper high-voltage part 5.

[0064] The contactor 1 of the present invention is a monostable element, and the monostable element is provided with normally open contacts according to the needs of most customers.

[0065] The moving contacts 21 and 22 inside the upper high-voltage section 5 abut against each other to allow high DC current to pass through or flow. Advantageously, the electrical contacts 21 and 22 move symmetrically toward and away from each other.

[0066] The contactor 1 includes a pair of contacts 21 and 22 that are driven to move reciprocally and symmetrically toward and away from each other relative to a central contact position or abutment position.

[0067] like Figure 2 and 3 As shown, each movable contact 21 or 22 is positioned at the end of a corresponding elongated arm 25, 26 of the elbow mechanism 30. Arms 25, 26 are made of a conductive material, such as metal.

[0068] Above the contacts 21 and 22, but still part of the switch base portion 2, there are corresponding arc flow channels 23 and 24.

[0069] The arc channels 23, 24 are typically configured to help dissipate the arc 29 formed during the opening phase of the moving contacts 21, 22. Depending on the application, the arc channels may or may not be installed.

[0070] Each of the arc channels 23, 24 is electrically connected to a corresponding dissipation or arc-blowing coil 51, 52. Each coil 51, 52 is located at the shoulder of each moving contact 21, 22 of each arm 25, 26.

[0071] Each arc flow channel 23 or 24 is formed of a flat metal plate that extends above the corresponding moving contact 21 or 22 when the corresponding moving contact 21 or 22 is in the open or stopped position. Figure 6 As shown, the upper flat metal plate is bent on two lateral sides to have opposing flanges 44, 45, which partially and laterally protect the corresponding moving contacts 21 or 22.

[0072] Lateral metal flanges 44 and 45 represent bypass elements, which can attract the arc flow path according to the direction of DC current, such as... Figure 6 The arc-shaped curve in Figure 29 is shown.

[0073] Advantageously, each magnetic element 41 or 42 is located outside the corresponding flange 44 or 45 on the side of the moving contact 21 or 22.

[0074] Furthermore, polar extensions 50, i.e., metal plates, are provided on both sides of the moving contact elements 21 and 22. Figure 5 Only one plate 50 is shown because only half of the housing 10 is shown, but it should also be assumed that there is a corresponding plate in parallel position on the other side of the housing relative to the contacts 21, 22.

[0075] For the sake of completeness, we will now disclose the other parts of contactor 1 used for switching operations.

[0076] Figure 2 and 3 The elbow mechanism 30 shown includes a pair of legs 31 and 32, which engage at one end in a sliding hinge 33 that is movable along a vertical slot 19 of the frame 20. The legs 31 and 32 are made of an insulating material, such as a thermosetting material.

[0077] Each of the outriggers 31 and 32 has its opposite ends hinged to the corresponding ends of the arms 25 and 26 of the moving contacts 21 and 22, respectively. More specifically, each end of the arms 25 and 26 opposite to the moving contacts 21 and 22 is connected to the corresponding end of the outriggers 31 and 32.

[0078] Each arm 25 or 26 is pivotally supported in the frame 20 at a position roughly corresponding to one-third of the arm's total longitudinal length via corresponding pivots 27, 28.

[0079] The outriggers 31, 32 and arms 25, 26, together with corresponding hinge joints 33, form the elbow mechanism 30, which allows one of the moving electrical contacts 21 and 22 to be driven toward the other, and vice versa. The rods 31, 32 and arms 25, 26 are formed by a pair of identical parallel members connected together somewhat like truss beams.

[0080] Between each of the pivots 27 and 28 and the corresponding fixed terminal power contact 11 or 12, there are forks 47 and 48 made of a conductive material, such as metal.

[0081] Those fork arms 47, 48 are substantially connected to fixed terminal power contacts 11 and 12 to provide electrical continuity between the moving electrical contacts 21, 22 and the fixed terminal contacts 11, 12.

[0082] The elbow mechanism 30 is actuated by the low-voltage drive section 4, which will be disclosed below.

[0083] The hinge joint 33 is provided with a central annular elastic element 39, which contacts the actuating end of the low-voltage drive section 4 and can be considered as a buffer between the actuating end and the entire elbow mechanism 30. The hinge joint 33 is pushed along the vertical slot 19 by a sliding guide 39, which is not visible in the figures.

[0084] The low-voltage drive section 4 includes a coil 6 powered by a low-voltage reference potential (not shown), which is of a conventional type and driven by a suitable switching actuator.

[0085] The coil 6 acts on the rod 7, which extends horizontally and parallel to the bottom flange 13 of the contactor housing 10 inside the switch base portion 2. The rod 7 moves against the action of an elastic element 8 (e.g., a compressed, elongated spring).

[0086] The free end or distal end 14 of lever 7 is connected to one end of operating lever 15, which is pivotally mounted on fulcrum 16, which is fixed together with or integrated with the internal frame 20 of the switch base portion 2 of contactor 1.

[0087] The operating lever 15 has a first arm connected to the free distal end 14 of the lever 7 and another arm or second arm that moves freely about the fulcrum 16 when the operating lever 15 is actuated by the coil 6 and the lever 7.

[0088] The free end of the second arm acts on the hinge joint 33 of the elbow mechanism 30.

[0089] Finally, it should be noted that circuit 49 is configured to supply relevant voltage values ​​to coil 6 according to the different needs of the low-voltage drive section of the actuator. This circuit 49 is generally a voltage level converter suitable for receiving multiple different voltage values. According to this embodiment, two types of electromagnets or coils 6 have been considered: a high-voltage coil and a low-voltage coil with a control card to control the starting and holding currents. This electronic control of the main coil allows for a combination of high closing power and reduced power consumption during the holding phase.

[0090] Based on the foregoing description, the function of the contactor device 1 of the present invention is obvious.

[0091] According to the solution based on the present invention, there are no fixed contacts in the contactor device 1. Instead, there is a pair of movable contacts 21, 22, which are driven toward and away from each other relative to their contact positions.

[0092] According to the set initial conditions, the electromagnet 6 of the low-voltage drive section 4 is biased to move the lever 7, which engages with one end of a two-armed operating lever 15 pivotally hinged to the fulcrum 16.

[0093] The movement of lever 7 causes the free end of operating lever 15 acting on sliding hinge 33 of elbow mechanism 30 to move. Sliding hinge 33 moves freely up and down or axially along slot of frame 20 to push up or down, and this movement pushes the entire elbow mechanism 30 to provide corresponding closure or opening of the moving contacts 21, 22.

[0094] The structure of the doubly symmetrically moving contacts 21, 22 of the present invention allows for a physical spacing of at least 73 mm between the contacts, which allows for a reduction in the risk of electric arcing and makes the switching of the contactor device of the present invention particularly reliable in terms of insulation characteristics.

[0095] Contacts 21 and 22 open at twice the speed, and elbow mechanism 30 also ensures a greater distance between them.

[0096] The magnetic elements 41 and 42, located on both sides of the opposing flanges 44 and 45 of the arc flow channels 23 and 24, primarily allow the arc to circulate toward the top arc partition 3 when low switching currents are involved.

[0097] The contactor described in this invention can also be used as a switch in high AC current applications.

[0098] In the preceding lines, directional terms such as "forward," "backward," "front," "rear," "upward," "downward," "above," "below," "upward," "downward," "top," "bottom," "side," "vertical," "horizontal," "vertical," and "lateral," as well as any other similar directional terms, refer only to the device as shown in the figures and do not relate to any possible use of the device. Accordingly, when used to describe a contactor in an upright vertical position on a horizontal surface, these directional terms have only the meaning of identifying a part of the device relative to another part, as shown in the figures.

[0099] When used herein, the term "comprising" and its derivatives are intended to be open-ended terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers, and / or steps. This concept also applies to words with similar meanings, such as the terms "having," "comprising," and their derivatives.

[0100] Furthermore, when used in the singular, the terms “component,” “segment,” “part,” “section,” and “element” can have a dual meaning of a single part or multiple parts.

Claims

1. An improved switching device or contactor device (1) with high arc-extinguishing capability, said switching device or contactor device (1) comprising, within a housing (10): - Switch base portion (2), the switch base portion (2) includes an electrical switching device (35) that acts on a low voltage drive portion (4) on moving contacts (21, 22). - A high-voltage section (5), the high-voltage section (5) comprising moving contacts (21, 22) driven relative to each other and away from each other at their respective contact positions, the moving contacts (21, 22) being mounted at corresponding contact ends of the elbow mechanism (30), the elbow mechanism (30) being movable by the low-voltage drive section (4); and - The top arc extinguishing part (3) covering the high voltage part (5). The characteristic feature is that the switching device or contactor device (1) comprises: Hardware device (40) disposed near the moving contacts (21, 22) to influence the arc (29) generated when the moving contacts (21, 22) connect and disconnect current as they move toward and away from each other. The corresponding arc flow channels (23, 24) are disposed above each corresponding moving contact (21, 22) in the open or stopped position, and the hardware device (40) is a magnetic element (41, 42) positioned on both sides of each arc flow channel (23, 24). The magnetic elements (41, 42) are positioned on each lateral side of each moving contact (21, 22).

2. The improved switching device or contactor device (1) according to claim 1, characterized in that, The hardware device (40) includes magnetic elements (41, 42) positioned close to the moving contacts (21, 22) to generate a magnetic field sufficient to partially circumvent the arc (29) when low switching currents are involved.

3. The improved switching device or contactor device (1) according to claim 2, characterized in that, The magnetic elements (41, 42) are permanent magnets.

4. The improved switching device or contactor device (1) according to claim 2 or 3, characterized in that, The magnetic elements (41, 42) are positioned on one side of each moving contact (21, 22).

5. The improved switching device or contactor device (1) according to claim 2 or 3, characterized in that, Each of the magnetic elements (41, 42) is configured as a disk, which is supported in a fixed position on the side of the corresponding moving contact (21, 22) when the moving contact is in the stopped or open position.

6. The improved switching device or contactor device (1) according to claim 1, characterized in that, It includes at least four magnetic elements (41, 42) and two contacts (21, 22) for each movement.

7. The improved switching device or contactor device (1) according to claim 1, characterized in that, The hardware device (40) functions to cause the electric arc to circumvent the top arc extinguishing portion (3).

8. The improved switching device or contactor device (1) according to claim 1, characterized in that, The hardware device (40) primarily functions when it is necessary to disconnect low current.

9. The improved switching device or contactor device (1) according to claim 1, characterized in that, Each arc flow channel (23, 24) is electrically connected to a corresponding arc-blowing coil (51, 52) located at the shoulder of each moving contact (21, 22).

10. The improved switching device or contactor device (1) according to claim 1 or 9, characterized in that, Each arc flow channel (23, 24) is formed of a flat metal plate extending above the corresponding moving contact (21, 22) and curved laterally on both sides to have opposing flanges (44, 45), which partially and laterally protect the corresponding moving contact (21, 22); the magnetic elements (41, 42) are positioned on both sides of the opposing flanges (44, 45).

11. The improved switching device or contactor device (1) according to claim 2 or 3, characterized in that, The magnetic elements (41, 42) are supported in the housing (10) in an inclined position perpendicular to the corresponding moving contacts (21, 22).

12. The improved switching device or contactor device (1) according to claim 1, wherein the improved switching device or contactor device (1) is used for switching high DC current.

13. The improved switching device or contactor device (1) according to claim 1, characterized in that, The improved switching or contactor device (1) is used in industrial and railway applications where high currents must be switched on and off.

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