High thermal efficiency electric switch and method for interrupting electric current
10347439 · 2019-07-09
Assignee
Inventors
Cpc classification
H01H9/40
ELECTRICITY
H01H19/56
ELECTRICITY
International classification
H01H19/56
ELECTRICITY
H01H9/40
ELECTRICITY
Abstract
An electric switch includes a first and a second connection terminal for connecting the switch to an external circuit; a first switch assembly, which includes two or more electric breaker elements connected in series to one another and to the first and the second connection terminal; a second switch assembly, which includes at least one delayed electric breaker element connected in parallel to the first switch assembly. A moving actuator is made of insulating material and is associated with the first and the second switch assembly to open or close them. The moving actuator is movable between a closed switch position in which electrical continuity is established between the first and the second connection terminal, and an open position in which current flow between said terminals is prevented.
Claims
1. An electric switch comprising: a first and a second connection terminals for connecting the switch to an external circuit; a first switch assembly comprising two or more electric breaker elements connected in series to one another and to the first and the second connection terminals; a second switch assembly comprising at least one delayed electric breaker element connected in parallel to the first switch assembly, wherein the second switch assembly is adapted so that it has less electrical resistance than the first switch assembly; and a moving actuator made of insulating material associated with the first and the second switch assembly to open or close them, wherein the moving actuator is movable between a closed switch position in which electrical continuity is established between the first and the second connection terminals, and an open position in which current flow between said terminals is prevented, wherein the second switch assembly is configured for being closed in the switch closing operation after the first switch assembly closes, such that when the second switch assembly is closed, the first switch assembly is short-circuited, and wherein the first switch assembly is constructed such that the two or more electric breaker elements open and close simultaneously.
2. The electric switch according to claim 1, wherein the electric breaker elements of the first switch assembly comprise two fixed contacts and one moving contact that can be contacted on the fixed contacts in a sliding manner, and wherein the at least one delayed electric breaker element of the second switch assembly comprises two fixed contacts and one moving contact that can be connected with the two fixed contacts, and wherein the second switch assembly has fewer electric breaker elements connected in series between the connection terminals than the first switch assembly, such that the second switch assembly has less electrical resistance than the first switch assembly.
3. The electric switch according to claim 2, wherein the second switch assembly is configured such that the path the moving contact of the second switch assembly must travel until contacting with its respective fixed contacts is longer than the path that the moving contacts of the first switch assembly must travel until contacting with its respective fixed contacts, such that in the electrical switch closing operation, the second switch assembly closes after the first switch assembly closes.
4. The electric switch according to claim 2, wherein the moving contacts of the first switch assembly are a substantially sinusoidal-shaped or substantially S-shaped metal plate.
5. The electric switch according to claim 1, configured so that the moving actuator can be moved with at least one linear movement component along an axis (X).
6. The electric switch according to claim 1, configured so that the moving actuator can rotate about an axis (X) and on a plane transverse to said axis.
7. The electric switch according to claim 1, wherein the moving contacts of the first and the second switch assembly are mounted in said moving actuator, such that they can move jointly with same.
8. The electric switch according to claim 1, comprising a casing made of electrically insulating material, and wherein the connection terminals and the fixed contacts of the first and the second switch assembly are mounted in said casing, and wherein the moving actuator is movably mounted in the casing.
9. The electric switch according to claim 1, wherein the moving actuator is an elongated slide and is linearly movable along an axis (X), and is arranged longitudinally according to the direction of said axis (X), and wherein the moving contacts of the first and the second switch assembly have two ends and are mounted in the slide, such that a first end of each moving contact projects from a first side face of the slide, and a second end of each moving contact projects from a second side face of the slide opposite the first face, and wherein the fixed contacts of the first and the second switch assembly are facing one another in pairs and placed on opposite sides of the slide in order to be contacted by its associated moving contact.
10. The electric switch according to claim 1, wherein the moving actuator is a rotor having an elongated body which is movably mounted inside a casing, and wherein the switch incorporates means for rotating the rotor inside the casing about an axis (X) without axial movement, and wherein the moving contacts of the first switch assembly are mounted in said rotor and are jointly movable with the rotor.
11. The electric switch according to claim 10, wherein the moving contacts of the first switch assembly are identical and are mounted in a same angular position in the rotor with respect to the axis (X), and wherein each moving contact has a first and a second end and is configured such that said ends can be accessed from diametrically opposing points outside the rotor with respect to the axis (X).
12. The electric switch according to claim 10, wherein a first group of fixed contacts of the first switch assembly are aligned according to a straight line parallel to the axis (X) in one side of the rotor, and a second group of fixed contacts of the first switch assembly are aligned according to a straight line parallel to the axis (X) in the other side of the rotor, and wherein one of the fixed contacts of the first group is connected with a connection terminal, and another one of the fixed contacts of the second group is connected with another connection terminal.
13. The electric switch according to claim 10, wherein the moving contacts of the first switch assembly are a substantially sinusoidal-shaped or substantially S-shaped metal plate.
14. The electric switch according to claim 1, wherein the moving actuator comprises a first rotor in which the moving contacts of the first switch assembly are mounted, and a second rotor in which the at least one moving contact of the second switch assembly is mounted, wherein the first rotor is helically movable with respect to said axis (X), and wherein the second rotor is mounted coaxially to the first rotor with respect to said axis (X) and is rotatable about said axis (X) on one and a same plane, and wherein the first and the second rotor are coupled to one another such that can rotate at a same time about the axis (X).
15. The electric switch according to claim 14, wherein the moving contacts of the first switch assembly are identical and are mounted in a same angular position in the rotor with respect to the axis (X), and wherein each moving contact has a first and a second end and is configured such that said ends can be accessed from diametrically opposing points outside the rotor with respect to the axis (X).
16. The electric switch according to claim 14, wherein the moving contacts of the first switch assembly are a substantially sinusoidal-shaped or substantially S-shaped metal plate.
17. A method for controlling electric current flow through an electric line using the electric switch defined in claim 1, which comprises: connecting in series in said line the first switch assembly formed by the two or more electric breaker elements connected to one another in series, connecting the second switch assembly in parallel to the first switch assembly, wherein said second switch assembly has less electrical resistance than the first switch assembly, simultaneously closing the breaker elements of the first switch assembly to allow current flow through the electric line, keeping the second switch assembly open, and closing the second switch assembly after an established time period to short-circuit the first switch assembly, such that the electric current in the line then flows through the second switch assembly.
18. The method according to claim 17, which further comprises opening the second switch assembly while the breaker elements of the first switch assembly are closed, such that the current in the line then flows in its entirety through the first switch assembly, and then simultaneously opening the breaker elements of the first switch assembly to interrupt current flow through the electric line.
19. The method according to claim 17, wherein the second switch assembly comprises at least one electric breaker element connected in parallel to the first switch assembly, and wherein the electric breaker elements of the first and the second switch assembly respectively comprise at least two fixed contacts and one moving contact that can be connected with the associated fixed contacts, and wherein the method comprises simultaneously moving the moving contacts of the electric breaker elements of the first and the second switch assembly.
20. The method according to claim 17, which further comprises simultaneously moving each moving contact of the electric breaker elements of the first switch assembly linearly along an axis X, or helically with respect to an axis X, or rotationally on one and a same plane and with respect to an axis X.
21. The method according to claim 17, which further comprises moving the at least one moving contact of the second switch assembly simultaneously with the moving contacts of the first switch assembly, and wherein the moving contacts of the first and the second switch assembly move linearly along an axis X, or wherein the moving contacts of the first and the second switch assembly move helically or rotationally with respect to an axis X, and the moving contact of the second switch assembly moves rotationally on one and a same plane and on said axis X.
22. The method according to claim 17, which comprises actuating the first and the second switch assembly by means of one and the same moving actuator common to both switch assemblies, and wherein the first and the second switch assembly are part of the same switching device and are mounted inside one and a same casing.
Description
DESCRIPTION OF THE DRAWINGS
(1) To complement the description being made and for the purpose of helping to better understand the features of the invention according to a preferred practical embodiment thereof a set of drawings is attached as an integral part of said description where the following is depicted with an illustrative and non-limiting character:
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PREFERRED EMBODIMENT OF THE INVENTION
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(22) Each of the breaker elements (2a, 2b, 2c, 3) of the switching device is formed by two fixed contacts (2a, 2b, 2c, 3) interconnected with the remaining fixed contacts as seen in the drawing, and a moving contact (2a, 2b, 2c, 3) that can be connected to and disconnected from its respective fixed contacts.
(23) All the moving contacts (2a, 2b, 2c, 3) are mounted in one and the same body called moving actuator (not depicted in
(24) Any technique or means can be used to obtain delayed connection of the delayed breaker element (3) with respect to the three breaker elements (2a, 2b, 2c), which will also depend on each type of switch in which the invention is implemented. Said delay is preferably achieved by making the maximum gap between the moving contact (3) and the fixed contacts (3) of the delayed breaker element (3) larger than the gap between each moving contact (2a, 2b, 2c) of the breaker elements (2a, 2b, 2c) and its respective fixed contacts (2a, 2b, 2c, 3), as illustrated in
(25)
(26) For the switch closing operation, the method comprises first closing the first switch assembly (1) and keeping the second switch assembly (4) open, and after an established time period after the first switch assembly (1) closes, closing the second switch assembly (4) such that the current (I) then flows through the second switch assembly (4).
(27) Furthermore, the method of the invention comprises actuating the first and the second switch assembly by means of one and the same operating element, specifically by means of a moving actuator common to both switch assemblies. Therefore, successive connection of the first and the second switch assembly is obtained in the same operation, i.e., with a single movement, so both switch assemblies can be operated in a manner conventional with one and the same mechanism external to the device.
(28) The moving contacts of the first and the second switch assembly move at the same time, however the invention enables the type of movement to be different for each switch assembly. Therefore, in a preferred embodiment the method of the invention comprises moving the moving contacts of the first and the second switch assembly simultaneously with a linear movement component along an axis (X). In another preferred embodiment, the method of the invention comprises moving the moving contact (3) rotationally on one and the same plane and about an axis (X), whereas the moving contacts of the first switch assembly simultaneously move helically with respect to an axis (X), or alternatively in another preferred embodiment of the invention, the moving contacts of the first and the second switch assembly move simultaneously by rotating them with respect to an axis (X) but without moving forward along the axis.
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(30) Each moving contact (2a, 2b, 2c) of the first and the second switch assembly (1, 4), is mounted in the slide (7) transverse to said axis (X), and such that a first end of the moving contacts projects from a first side face of the slide, and a second end of the moving contacts projects from a second side face of the slide opposite the first face. Preferably, all the moving contacts (2a, 2b, 2c) have the same shape and size, and consist of a straight elongated metal plate.
(31) The fixed contacts (2a, 2b, 2c, 3) are mounted in a fixed position of the casing (8) of the switch and arranged in pairs opposite one another on different sides of the slide (7) and arranged for being contacted by the respective moving contact (2a, 2b, 2c, 3). The moving contacts (2a, 2b, 2c) and their respective fixed contacts (2a, 2b, 2c, 3) are configured and positioned such that they come into contact but in a sliding manner, i.e., they contact one another at the same time that they slide as the slide moves. The slide (7) is arranged between the fixed contacts.
(32) It can be seen in
(33) The movement of the slide (7) in a switch closing operation follows the sequence of
(34) It can now be seen more clearly in this embodiment that said delay in closing the delayed contact (3) is achieved by suitably placing the fixed and moving contacts with respect to one another to make the maximum gap (d2) that the moving contact (3) of the second switch assembly must travel until contacting with its fixed contacts (3) is greater than the maximum gap (d1) that each moving contact (2a, 2b, 2c) of the first switch assembly (1) must travel until contacting with their respective fixed contacts (2a, 2b, 2c).
(35) In other words, the path or time from the furthest or maximum point that the moving contact of the second switch assembly must travel until contacting with its fixed contacts is longer than the path (from the furthest or maximum point) that the moving contacts of the first switch assembly must travel until contacting with their fixed contacts, such that in the electrical closing operation the second switch assembly closes after the first switch assembly closes.
(36) In other embodiments of the invention, the delay in closing the delayed contact (3) can be obtained by changing the position and/or shape of the moving contact of the second switch assembly.
(37) Finally, in the position of
(38) In the switch opening operation, the movement of the slide and the connections are opposite those described above, i.e., with a sequence of movements from the position of
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(41) In this embodiment, the actuator is formed by two parts, a first rotor (15) and a second rotor (23) both coupled to one another and simultaneously movable, but with different movements as will be described below. The moving contacts of the first switch assembly are mounted in the first rotor (15), and the moving contact of the second switch assembly is mounted in the second rotor (23).
(42) The first rotor (15) is an elongated body placed longitudinally in the direction of the axis X, and is preferably formed by two parts (15, 15) coupled to one another. The first rotor (15) is mounted inside the casing (8, 8) such that it is able to slide over an inner surface thereof and move in a helicoidal manner with respect to said axis X, i.e., the switch has means for making the rotor (15) move with a linear movement component with respect to the axis X and simultaneously with a rotational movement component with respect to the same axis X.
(43) The second rotor (23) is in the form of a reel and is mounted coaxially to the first rotor (15) with respect to the axis X, and is likewise mounted inside the casing (8, 8) such that it is able to slide over an inner surface thereof. Unlike the first rotor (15), this second rotor (23) is configured together with the casing such that the linear forward movement on the axis X is prevented, i.e., it can only rotate about the axis (X), staying in one and the same plane without moving forward along the axis.
(44) The first and the second rotor (15, 23) are coupled to one another such that each one can perform the movements described above, and such that the first and the second rotor are integral in the rotational movement, i.e., they rotate at the same time about the axis (X), however the first rotor (15) can move forwards and backwards longitudinally on the axis (X), whereas axial movement of the second rotor (23) is prevented. This coupling between both rotors and the relative movement between both is illustrated in
(45) The coupling between the first and the second rotor (15, 23) is a male-female coupling and is formed by a cavity (25) existing in the first rotor (15) and a prolongation (24) projecting from the second rotor (23) and introduced in said cavity (25), where the cavity and the prolongation are arranged axially on the axis (X) and have a matching shape, as is more clearly seen in
(46) It can be seen in the sequence of
(47) Such coupling between both rotors on one hand enables the first and the second switch assembly (1, 4) to be operable at the same time by means of the same operating mechanism, and on the other hand, since both the first and the second switch assembly (1, 4) have different functionalities, it enables being able to optimize the design of their contacts for the specific function they have to perform. In that sense, it can be observed that the moving contacts (2a, 2b, 2c) of the first switch assembly (1) are a thin metal plate since the contact surface with the respective fixed contacts should be very small to make it easier to quench arcs.
(48) On the other hand, the moving contact (3) of the second switch assembly (4) is formed by two planar metal plates (30, 30) superimposed in a matching position which are mounted in the second rotor (23), such that the ends of these plates project from the rotor forming respective clamps at each end used for gripping by applying pressure on the respective fixed contacts (3, 3) of the second switch assembly. This configuration of the second switch assembly (4) is optimal for functionality because in the current conduction permanent state, there should be maximum contact surface between the terminals to make current flow easier.
(49) For the same purpose, there is a pair of strips (31, 31) mounted in the second rotor (23) and placed to apply pressure (due to their elastic property) respectively on the ends of respective metal plates (30, 30) against the fixed contacts (3, 3) and thereby assure proper contact between both elements at all times.
(50) In this embodiment a disc-shaped wall (20) made from an insulating material, preferably forming an integral part of the second rotor (23) and configured such that it defines inside the casing (8) and on each of its sides respective chambers insulated from one another by the wall (20) so that the first and the second switch assembly (1, 4) are housed respectively in said chambers (21, 22), is arranged, thereby preventing the electric arc from being able to hop from one switch assembly to the other since they are separated by the wall (20).
(51) The aforementioned means for obtaining helicoidal movement of the first rotor (15) can be obtained by configuring the rotor and the stator as if they were a screw and a nut, respectively, coupled by means of threading. Alternatively, the means for the helicoidal movement can be obtained by means of an external actuation mechanism (16) coupled to the rotor and configured to produce said helicoidal movement.
(52) Another aspect of the invention relates to an actuation mechanism (16) for converting rotational movement into helicoidal movement to produce the helicoidal movement of the first rotor (15). Said mechanism (16) is formed by a fixed body (32) having a through cavity (33) extending along an axis (X), and said body provided with two guide surfaces (34) parallel to one another and arranged in an inclined manner with respect to said axis (X), said guide surfaces (34) being arranged around said through cavity (33). A moving rod (35) is movably housed inside said through cavity, the moving rod being provided with a lug (36) projecting in the radial direction with respect to an axial axis of the rod, where said lug is arranged tightly between said guide surfaces, such that it can slide on them, contacting with both surfaces. That mechanism (16) is also mounted in the casing (8, 8) and during use it is operated by means of another conventional external mechanism (not depicted) for actuating such switches, which applies a rotation torque on the rod (35) which is transformed into helicoidal movement by the mechanism (16).
(53) On the other hand, the switch incorporates a group of deionizing plates (17) placed close to the fixed and moving contacts and close to the gas exhaust windows (14) of the casing.
(54) The moving contacts (2a, 2b, 2c) of the first switch assembly (1) are mounted in the rotor (15) and are therefore moved by the rotor as well following a helicoidal path. Preferably, as shown in
(55) On the other hand, all the fixed contacts of the two switch assemblies (1, 4), are conveniently mounted in fixed positions of the casing (8, 8) for being contacted by the respective moving contacts.
(56) Another aspect of the invention relates to the shape of the moving contacts (2a, 2b, 2c) of the first switch assembly, which is shown in
(57) Unlike the embodiment of
(58) The pairs of fixed contacts (2a, 2b, 2c) are placed on a plane (Y), as can more clearly be seen in
(59) The fixed contacts (2a, 2b, 2c) are in the form of a plate, and one of them is connected with the connection terminal (5) and another one is connected with the other connection terminal (6). In this embodiment, there are three fixed contacts on one side of the axis X, another three on the other side of the axis X, and five moving contacts.
(60) The pair of fixed contacts (3) of the delayed breaker element (3) is connected respectively with the terminals (5, 6) and has one end in the form of a tongue suitable for being introduced into the ends in the form of a clamp of the moving contact (3) described above. Another characteristic aspect of these fixed contacts (3) is their displaced or shifted position in relation to the position of the fixed contacts (2a, 2b, 2c) of the first switch assembly, because one of these fixed contacts (3) is aligned on a plane (Z) positioned on one side of the plane (Y) and parallel to same, whereas the other fixed contact (3) is aligned on a plane (R) and parallel to same, positioned on the other side of the plane (Y). The moving contact (3) of the delayed breaker element (3) is placed in the same angular position as the moving contacts (2a, 2b, 2c, 2d, 2e), as can be observed in
(61) Said displaced position of the fixed contacts (3) makes the delayed breaker element (3) close after the breaker elements of the first switch assembly. In other embodiments, that same function can be obtained in another way, for example by moving back the position of the moving contact (3) and aligning the fixed contacts (3) with the fixed contacts of the first switch assembly.
(62) The helicoidal movement of the moving contacts (2a, 2b, 2c, 2d, 2e) is depicted in the sequence of
(63) In
(64) In
(65) In
(66) In
(67) In
(68) The sequence of
(69) In other embodiments, it may be of interest for the first rotor to not move helically, but rather to simply rotate on the axis (X) without moving longitudinally. That is the case of the embodiment shown in
(70) In this embodiment, the first and the second rotor are completely integral with one another because both move in the same way, rotating on the axis (X) without axial movement, so they functionally act like one and the same body. Therefore, in a practical embodiment a single rotor (15) can be arranged in which the moving contacts of the first and the second switch assembly are mounted, as shown by way of example in
(71) Otherwise, operation of the switch of
(72) The invention therefore achieves a helicoidal or angular elongation of the length of the electric arc in a small space, which means that for one and the same nominal interruption current, the switch can be smaller when compared with a switch from the state of the art.
(73) As a result of the helicoidal or angular movement tangential speed of the interruption point is increased depending on the radius of rotation, thereby increasing the interruption speed in a simple manner, without requiring complex mechanisms and with a small number of parts, so manufacturing the switch is very simple.
(74) One of the advantages of this embodiment is that since there is not contact or impact between the rotor and any other component of the switch, the rotor can be manufactured with materials such as glass or porcelain, which are highly insulating materials compared with plastic insulating materials.
(75) The various embodiments and alternatives herein described can be combined with one another, giving rise to other embodiments, such as those obtained with the multiple combinations of the attached claims, for example.