EP4109486A1

EP4109486A1 - Safety device and three-pole base

Info

Publication number: EP4109486A1
Application number: EP21756447.5A
Authority: EP
Inventors: Pablo Paunero Quijada
Original assignee: Talleres Electromecanicos L Pinazo SA
Current assignee: Talleres Electromecanicos L Pinazo SA
Priority date: 2020-02-19
Filing date: 2021-02-18
Publication date: 2022-12-28
Also published as: ES1243729Y9; ES1243729U; WO2021165561A1; EP4109486A4; ES1243729Y1

Abstract

Safety device and three-pole base. The device (1) comprising a series switch element (104) with a fuse (103), the switch (103) having an open state and a closed state; a manual actuator (105) for opening and closing the switch element (104); measuring means (106) for measuring at least one operational parameter of the device (1); and a control module (107) for performing a disabling when the operational parameter meets a predetermined condition; wherein said disabling comprises acting on the switch element (104) in order to move the switch element (104) from the closed state to the open state.

Description

Field of the Invention

The invention is comprised in the field of electrical installations, particularly in the field of electric distribution panels comprising three-pole fuse bases.
More specifically, the invention relates to an electrical safety device configured to be installed in a three-pole fuse base, comprising two terminals between which there is defined an electrical branch, said branch being provided with a fuse configured to cut off the passage of electric current in said branch in the case of blowing.
The invention also relates to a corresponding three-pole fuse base.

State of the Art

In the field of electrical installations, the use of fuses intended for blowing when the intensity of the current exceeds a threshold, thereby cutting off the passage of current, is common. This blowing is generally not instantaneous, but rather requires said threshold to be exceeded for a given time window. Therefore, by selecting fuses with the appropriate characteristics, it is possible to create safety elements which impede the circulation of too high currents which could cause damage or accidents downstream. Particularly, in the field of low-voltage installations, three-pole fuse bases, in which three of said fuses are inserted, are used.
Such devices have an enhanced safety, given that they represent a physical cut-off in situations of excessive current. However, they have the drawback of having to replace the fuse, once blown, with a new one, which increases maintenance costs. Furthermore, in cases in which it is necessary to cut off the electrical power to perform operations with the lines, an operator must physically remove the fuse, in order to thereby cut off the passage of current.
For these reasons, alternative solutions to fuses, for example circuit breakers, have also emerged. These devices are calibrated to cut off the current under specific conditions, usually by means of bimetals. They have the advantage of allowing a resetting after a cut-off, generally by means of a manual actuator, or else by means of a motorized remote control, which largely reduces maintenance costs in comparison with fuses.
However, both devices based on fuses and devices based on circuit breakers have the drawback of the difficulty in adapting the same device for different current cut-off situations. Furthermore, the usual breakers are not particularly suited to the voltage and current conditions in low-voltage installation distribution centers. Particularly, the safety level offered by said breakers can be lower than that offered by fuses.
Accordingly, an electrical safety device which allows a high safety level and which, at the same time, lowers maintenance costs and provides flexibility in terms of the selection of the line cut-off criteria, is advisable.

Description of the Invention

The purpose of the invention is to provide an electrical safety device of the type indicated above, which allows the problems set forth above to be overcome.
This purpose is achieved by means of an electrical safety device of the type indicated above, characterized in that it further comprises:

a switch element, provided in said branch and connected in series with said fuse, said switch element having a closed state in which it allows the passage of electric current, and an open state in which it impedes the passage of electric current;
a manual actuator, configured to move said switch element from said closed state to said open state and vice versa;
measuring means, configured to measure at least one operational parameter of said safety device; and
a control module, configured to perform a disabling in the event that said at least one operational parameter meets a predetermined condition, wherein said disabling comprises acting on said switch element in order to move said switch element from said closed state to said open state.

The switch element and the fuse are thereby connected in series. Therefore, the switch element acts as a first cut-off line, whereas the fuse provides added safety: even if the switch would fail, if the current is excessive, the fuse will perform its function and cut off the line. In turn, disabling of the switch element is controlled by means of the control module, which allows one and the same device to be used for different predetermined conditions, for example, different current thresholds, temperature thresholds, etc. Said predetermined condition is based on an operational parameter measured in the device itself by the measuring means. Accordingly, under normal operation, the line is cut off by means of the switch element, based on a predetermined condition which can be adapted to each installation, thereby providing flexibility to the device. Given that in this normal operation, there is no blowing of the fuse, it is not necessary to replace said fuse in the event of a cut-off, thereby minimizing maintenance costs. Nor is it necessary for an operator to remove the fuse in order to cut off the line, given that the manual actuator allows this operation by acting on the switch element.
Moreover, should any element, for example, the switch element or the control module, fail and the line is not cut off, the fuse provided in the device will blow. The safety level of the device is thereby equivalent to that of the fuses used in the art, but including the technical advantages described above during normal operation.
Preferably, said control module is further configured to perform a resetting, which comprises acting on said switch element, in order to move said switch element from said open state to said closed state, which allows the possibility of resetting the device again without the need for an operator to physically go to the location where the device is used for resetting by operating said manual actuator.
Preferably, said control module is further configured to start said resetting when a predetermined resetting time has elapsed since said disabling. This allows automatic resetting once a predetermined time has elapsed, providing the device with autonomy, allowing, in an autonomous manner, the device to be reset and allow the passage of current through the line without needing the intervention of an operator. This type of functionality is particularly advantageous in situations, such as those in which current peaks, for example, due to lightning striking, take place.
Preferably, said control module is further configured to retry at least once if a disabling takes place immediately after said resetting, thereby increasing the autonomy of the device with respect to the resetting. Preferably, the total number of retries is limited to a predetermined value of retries, such that retries are not performed if the conditions causing the line to be cut off are maintained for a prolonged period, which generally implies that it is not an isolated problem.
Preferably, said operational parameters comprise an electric current measurement in said branch, and said predetermined condition comprises at least one of the conditions where:

said electric current measurement exceeds a threshold current; and
said electric current measurement exceeds a threshold current during a threshold time.

The first condition is met when a current threshold value is exceeded, whereas the second condition requires a threshold current to be exceeded for a time window. Both threshold currents can be different. The device can thereby be disabled in the case of isolated current peaks and/or when there is a prolonged increase in current. Preferably, for the second condition, said threshold time depends on said threshold current, such that the higher the threshold current is, the lower the threshold time is.
Preferably, said measuring means comprise a first toroidal current transformer arranged surrounding an electrical conductor of said branch. This allows a current measurement to be taken on the current circulating through the branch through the current induced in said toroidal transformer. The measurement does not need any bypass circuit of the branch itself, nor does it require other elements to be placed in series. Furthermore, the current in the measuring circuit is isolated from the current circulating through the branch, which improves safety and particularly minimizes the risk of an excessive current being able to cause damage in the measuring means.
Preferably, said device further comprises a second toroidal current transformer configured to electrically power said control module, such that external power supply for the device is not needed. Furthermore, similarly to the case of the measurement through the first toroidal transformer, the supply circuit emerging from the second toroidal transformer to supply power to the device is electrically isolated from the main branch, thereby increasing device safety and robustness.
Preferably, said operational parameters further comprise at least one of:

a temperature measurement;
a current measurement; and
a voltage measurement.

This allows said predetermined condition to be adapted to the physical and operating conditions in which the device can be found, which involves an increased safety and greater flexibility in determining when the device should be disabled, it even being possible for the predetermined condition to combine several of said measurements, which would be impossible in the devices currently known in the art.
Preferably, said control module further comprises remote connection means configured to at least one of:

sending said operational parameters; and
receiving commands.

It is thereby possible to remotely monitor the operation of the device and/or to remotely send orders to the control module for said module to perform specific actions. This increases safety and facilitates equipment maintenance, potentially minimizing the cost of said maintenance or minimizing the time needed for maintenance operations.
Preferably, said commands comprise at least one of:

a configuration command;
a command for starting said disabling; and
a command for starting said resetting;

Preferably, said configuration command comprises at least one of:

a command for modifying said predetermined condition, which allows the conditions in which the device must be disabled automatically to be modified;
a command for modifying said predetermined resetting time, which allows the automatic resetting to be reprogrammed in order to increase or decrease the necessary time; and
a command for modifying said predetermined value of resetting retries, which allows the device to be adapted to different conditions.

The orders for configuration furthermore allow the remote and preferably centralized modification of parameters such as those herein set forth. This has the additional advantage that, should it be necessary to comply with different regulations over time, it is not necessary to physically act on or replace the device, but rather simply send the corresponding orders for remote configuration.
Preferably, said switch element comprises a vacuum interrupter of the type comprising:

a bottle, in which two electrical contacts are provided arranged in a vacuum medium;
a first fixed terminal, attached to a first fixed rod, which communicates with the interior of said bottle and is attached to one of said electrical contacts;
a second mobile terminal, attached to a second mobile rod, which communicates with the interior of said bottle and is attached to the other one of said electrical contacts;

Vacuum interrupters, sometimes called vacuum bottles, are elements that have frequently been used in medium- or high-voltage applications. However, their use in low-voltage applications with high current intensities, as in the case of the three-pole fuse bases, is unknown. Therefore, an object of the invention relates to the use of vacuum interrupters as a switch element for electrical safety devices configured to be installed in three-pole bases. This type of switch has the advantage that the distance that the elements thereof must move for opening and closing the passage of current is very short in comparison with switches of another type, such as breakers based on bimetals. The reason is the high electric strength of the vacuum inside the bottle, which minimizes the occurrence of electric arcs. This short distance allows the resulting safety device not to require large mechanical movements either and the operating time of vacuum interrupters to be very rapid in comparison with other known alternatives. Other additional advantages of vacuum interrupters in comparison to other switches known for low-voltage environments consist of said interrupters having a lower weight and cost, requiring less maintenance, and having a longer service life.
Preferably, said device further comprises a controllable actuator configured to move said second terminal from said proximal position to said distal position or vice versa; wherein said control module is configured to act on said switch element by means of said controllable actuator. The vacuum interrupter requires a mechanical action on its second mobile terminal to move it to the open or closed position. The use of a controllable actuator allows this mechanical action to be performed, whereas the control electronics of the control module is in charge of determining when said action is necessary.
Preferably, said controllable actuator comprises:

a rocker lever, configured to rock about a rocking shaft between a first rocking position and a second rocking position, said lever having a first segment on a first side of the shaft and a second segment on a second side of the shaft, opposite said first side;
operating means, configured to act on said lever from said second segment for moving said lever between said first rocking position and said second rocking position and vice versa;
securing means, arranged in said first segment and configured to secure said lever to said second mobile terminal, such that, in said first rocking position, said second terminal is in said proximal position, and in said second rocking position, said second terminal is in said distal position; and
locking means, configured to lock said second terminal in said proximal position when said lever is in said first rocking position.

The lever rocks about a shaft, and the operating means move said lever from one of the sides of the shaft. The skilled person will understand that the terms "first segment" and "second segment" are interchangeable in an equivalent manner. The same applies for "first side" and "second side". In that sense, when the operating means move the lever from a segment in one direction, said lever performs a seesaw-type movement about the shaft, moving the other segment of the lever in the opposite direction. The securing means secure the second mobile terminal, which allows the movement applied from the operating means to correspond to a movement of the second terminal from its proximal position to its distal position, or vice versa. It is thereby possible to cause the vacuum interrupter to move from the closed state to the open state, or vice versa. In the first rocking position, the second terminal is in the proximal position and the vacuum interrupter is in the closed state, whereas, in the second rocking position, the second terminal is in the distal position and the vacuum interrupter is in the open state. The arrangement by means of the rocker lever likewise allows the operating means to be arranged parallel to the bottle, which provides flexibility to the design of the device, particularly so that it can be used in three-pole fuse bases. Lastly, the function of the locking means is to impede the vacuum interrupter from unexpectedly opening, by means of locking the terminal in its proximal position. Indeed, in cases such as, for example, when there is an isolated current peak, a force that tends to separate the electrical contacts inside the bottle of the vacuum interrupter can be induced. If the separation is sufficiently rapid and the distance is large, the main effect is the disabling of the vacuum interrupter. However, in other cases, there can be overheating and said electrical contacts can even melt. These effects make it necessary to later replace the damaged device and can even cause situations of risk. The locking means overcome these problems, given that they impede the electrical connectors from moving away from one another, as they impede movement of the second terminal.
Preferably, said operating means comprise at least one electromagnet. Each electromagnet is controlled by the control means to move one side of the lever. This solution does not need any supplementary mobile parts, such as gears, motors, etc., whereby the reliability and service life are high. Preferably, two electromagnets are arranged separated by an access space, which facilitates the assembly of the device. In particular, the first terminal of the vacuum interrupter can be connected to one of the bars of a three-pole fuse base provided on the bottom of said base, which would make difficult to assemble the device on said base, if there is not said access space. Preferably, the lever is a planar part with a C-shaped side in which each end is operated by one of said electromagnets and the inner space leaves said access space free.
Preferably, each of said at least one electromagnet is further provided with a permanent magnet configured to maintain the position of said rocker lever in the event of losing electrical power in said electromagnet. The electromagnet thereby only needs to be operated, when the lever needs to be moved to one rocking position or the other. This lowers the power consumption of the device and prolongs its service life.
Preferably, said manual actuator comprises:

an actuator rod, arranged in a parallel direction with respect to said second mobile terminal of said vacuum interrupter and movable in said parallel direction, having a distal end relative to said vacuum interrupter and a proximal end relative to said vacuum interrupter;
a push button, secured to said actuator rod at said distal end;

Preferably, said securing means comprise:

a bushing, integral with said rocker lever, provided with a central through hole which said second terminal passes through and with lateral holes; and
a pin, arranged passing through said second terminal and extending perpendicular thereto and parallel to said rocking shaft, passing through said lateral holes.

The central through hole is configured with sufficient clearance to allow the second terminal to pass therethrough both in the first rocking position and in the second rocking position. By way of a preferred example, with a second cylindrical terminal, the central through hole has an oval shape with a minor axis parallel to the rocking shaft and a major axis perpendicular thereto. A similar consideration applies for the lateral holes and the pin. These configurations with the bushing and pin allow the rocking movement of the lever to be converted into a linear movement transmitted to the second terminal, which is needed for moving said terminal between its proximal and distal positions.
Preferably, said locking means comprise:

a mobile part comprising a body provided with a latch on a first side of the body, said mobile part being movably arranged along a straight line which is perpendicular to said second terminal and to said rocking shaft, between a locking position and a release position, or vice versa;
a spring, attached to said mobile part on a second side of the body opposite said first side of the body; and
a locking hole provided in said bushing and facing said latch in said first rocking position;

Therefore, in the release position, the latch is outside of the locking hole and the spring is in its standby position. In contrast, in the locking position, the spring is in a working position. In the context of the document, working position of the spring means that position in which said spring is subjected to a force that elastically deforms said spring. By way of non-exclusive examples, in the case of a draught spring, the working position corresponds to an elongated position, whereas, in the case of a compression spring, the working position corresponds to a compressed position. Therefore, in said locking position, the spring tends to pull the mobile part in the direction corresponding to the standby position of the spring, which tends to move the latch away from the hole. This has the effect that, if there is no element pushing the mobile part, the spring itself unlocks the locking means, whereby the second terminal tends to move towards its distal position to open the switch. On the other hand, when the lever moves from its second rocking position to its first position, the lower pushing portion is coupled to the upper pushing portion provided in the mobile part. The complementary ramp shape of both pushing portions has the effect of converting the rocking movement of the lever into a linear pushing of the part towards the second terminal. The pushing continues until, upon reaching the first rocking position, the latch is introduced in the locking hole, and the locking means impede the opening of the switch. In that sense, a linear pushing of the second terminal itself that tried to move said second terminal towards its distal position would be blocked by the latch and the locking hole. In contrast, a movement of the lever towards its second rocking position releases the force exerted by the lower pushing portion of the lever against the upper pushing portion of the mobile part, and the spring pulls said mobile part to release the latch from the locking hole. The result is an effective locking against undesired opening, but without the need to apply a large amount of energy for locking or unlocking. Accordingly, manual actuation is facilitated, and the energy requirements for the actuation controlled by the control module lessen.
Preferably, said mobile part further comprises:

a spring rod, having a first end attached to said body on said second side of the body, and a second end opposite said first end; and
a flange, attached to said spring rod at said second end;

Preferably, said vacuum interrupter is arranged vertically, such that said second mobile terminal is arranged, so as to be movable in the vertical direction, and wherein said fuse is arranged above said vacuum interrupter. In the context of the document, and unless otherwise indicated, directions will be understood as being relative to the attached figures. Fuse bases generally have a limitation imposed on their dimensions, particularly, in terms of the width of the fuses connected thereto. Usually, this limitation is imposed by the installation company, or a limitation is imposed by the regulations. The location of the fuse on the switch element allows the use of relatively wide components which would not comply with said imposition if they were arranged laterally. It is thereby possible to replace the current fuses in three-pole fuse bases with devices such as the device of the invention.
The invention also relates to a three-pole fuse base provided with at least one electrical safety device according to any of the forms described above.
The invention also comprises other detailed features illustrated in the detailed description of an embodiment of the invention and in the attached figures.

Brief Description of the Drawings

The advantages and features of the invention are apparent from the following description in which, in a non-limiting manner with respect to the scope of the main claim, preferred embodiments of the invention are disclosed in reference to the figures.

Figure 1 shows a perspective view of a three-pole fuse base provided with three safety devices according to an embodiment of the invention.
Figure 2 shows a safety device such as the one used in the fuse base of Figure 1 in an isolated manner.
Figure 3 is a detailed side view of the safety device of Figure 2, in which the external casing has been eliminated in order to see the internal elements.
Figure 4 is a perspective view corresponding to Figure 3.
Figure 5 is a detailed perspective view of the same device of Figure 4, in which the fuse has been eliminated.
Figure 6 is a detailed top view of the device of Figure 5, in which the connector emerging from the vacuum interrupter has furthermore been eliminated.
Figure 7 is a detailed side view of part of the safety device with the switch in the closed position and the rocker lever in the first rocking position. The walls of the vacuum interrupter have been eliminated to enable viewing the internal terminals.
Figure 8 is a side view equivalent to Figure 7 but with the switch in the open position and the rocker lever in the second rocking position.
Figure 9 and Figure 10 are detailed sides views of the safety device of the invention. Figure 9 shows the rocker lever in the first rocking position and the latch introduced in the locking hole, whereas Figure 10 shows the rocker lever in the second rocking position and the latch removed from the locking hole.

Detailed Description of Embodiments of the Invention

The figures show a first embodiment of the electrical safety device 1 of the invention, as well as of a corresponding three-pole fuse base 2.
Particularly, the device 1 of the invention is configured to be installed in a three-pole fuse base 2 such as the one in Figure 1, in which the base 2 is provided with three of said devices 1. Figure 2 shows the device 1 in an isolated manner. The device 1 comprises two electric terminals 101, 102 between which there is defined an electrical branch. In the embodiment shown in Figure 1 and Figure 2, the device comprises an external casing made of an electrically insulating material. The device 1 comprises a control module 107 arranged in an area of the casing configured to accept said control module 107. The functionality of the control module is described hereinbelow. Given that said external casing impedes viewing the rest of the internal components, for the sake of clarity, in the remaining Figures 3 to 10 said external casing has been eliminated. Likewise, the figures are simplified depictions of the device 1, and thus they do not show elements such as the internal wiring.
Figure 3 and Figure 4 show the main internal elements of the device 1 of the invention. Particularly, the figures show how the branch defined between the two terminals 101, 102 is provided with a fuse 103 intended to cut off the passage of electric current in said branch in the case of blowing. In the case of the example, the fuse is a blade fuse with a rated current value of 400 A, although in other embodiments of the device 1, fuses of other current values, suited to the type of application for which the safety device 1 is intended, are used.
The device 1 further comprises a switch element 104 provided in the branch and connected in series with the fuse 103. The switch element 104 of the example is a vacuum interrupter 150 with rated values of 400 A, 440 V, and 25 kA, effective for a 1-second short-circuit. The vacuum interrupter 150 has a closed state in which it allows the passage of electric current, and an open state in which it impedes the passage of electric current. The current, thereby, passes through the branch if both the fuse 103 and the vacuum interrupter 150 allow the passage. Such vacuum interrupters 150 are known, and thus, only the most relevant elements to understand the invention are described. The vacuum interrupter 150 of the example comprises a cylindrical bottle 155 depicted vertically in the figures. Inside said bottle 155, there are two electrical contacts 151, 152 arranged in a vacuum medium. Two terminals 153 and 154 emerge from the upper and lower ends of the bottle 155, from the central axis of the bottle 155. A first terminal 153 is fixed, whereas the second terminal 154 is mobile and can be moved vertically in a direction which coincides with the axis of the bottle 155 and is perpendicular to an outer surface of said bottle 155; in the example of the figures, said outer surface is the upper surface of the bottle 155. Therefore, the second terminal 154 can be moved vertically between a proximal position, in which the electrical contacts 151, 152 of the interior of the bottle 155 are in electrical contact and the vacuum interrupter 150 is in the closed state, and a distal position, in which the electrical contacts 151, 152 are separated and said vacuum interrupter 150 is in said open state.
In the case of the first exemplary embodiment, the terminals 153 and 154 are provided with screws to be able to attach them to busbars, although other equivalent forms of connection are possible, for example, a welded connection. The first terminal 153 is attached to an electric terminal 102 of the device 1, whereas the second terminal 154 is attached to the fuse 103 by means of a C-shaped conductive copper bar segment, conferring to it sufficient flexibility to absorb the vertical movements of the second terminal 154. As can be observed in Figures 3 and 4, the vacuum interrupter 150 is arranged vertically, such that the second mobile terminal 154 is arranged so as to be movable in the vertical direction, and the fuse 103 is arranged above said vacuum interrupter 150.
Figures 3 and 4 show how the safety device 1 also comprises measuring means, in this case, a first toroidal current transformer 106 arranged surrounding an electrical conductor of said branch emerging from the fuse 103 towards one of the electric terminals 101 of the device 1. This toroidal transformer 106 is configured to measure at least one operational parameter of the safety device 1. In the case of the example, said parameter is a measurement of the current circulating through the branch. For the sake of clarity, the electrical connections between the toroidal transformer 106 and the control module 107 are not depicted in the figures. Said control module 107 is configured to disable the device 1, in the event that the operational parameter, in this case the current measurement, meets a predetermined condition. For the first embodiment, a selector provided in the device 1 allows an operator to be able to previously determine a threshold current value in the range of 160-400 A. In the particular case of the first embodiment, said selector is a potentiometer connected to the control module 107, although other equivalent forms can be provided. Therefore, the predetermined condition is for the electric current measurement to exceed said selected threshold current during a threshold time of 0.1 second. The disabling performed by the control module 107 comprises acting on the switch element 104, in this case, the vacuum interrupter 150, in order to move said switch element 104 from the closed state to the open state.
Figure 5 shows the device 1 without the fuse 103 or the measuring means 106 such that other components can be observed more clearly. As shown in the figure, the device 1 further comprises a manual actuator 105 comprising an actuator rod 110 and a push button 111. The actuator rod 110 is arranged in a vertical direction, parallel to the second mobile terminal 154 of the vacuum interrupter 150 and movable in said direction. It has a distal end, away from the vacuum interrupter 150, and a proximal end, close to the vacuum interrupter 150. The push button 111 is secured to the actuator rod 110 at its distal end. The manual actuator 105 is configured to move the switch element 104 from the closed state to the open state and vice versa. The way this opening and closing of the switch element 104 is performed by the manual actuator 105 in the first embodiment is described below.
Figure 5 also shows that the device 1 further comprises a controllable actuator. Said controllable actuator is configured to move the second mobile terminal 154 of the vacuum interrupter 150 corresponding to the switch element 104 from its proximal position to its distal position or vice versa. In turn, the control module 107 is configured to act on the switch element 104 by means of said controllable actuator. The controllable actuator comprises a rocker lever 160 which, for the first embodiment, is a planar part with a C-shaped side. Figure 6 shows a detailed top view which shows the arrangement of the rocker lever 160, which is configured to rock about a rocking shaft 161 between a first rocking position and a second rocking position. Figure 5 and Figure 6 depict said rocking shaft 161 as a discontinuous line superimposed on the figure. The lever 160 has a first segment 162 on a first side of the shaft 161 and a second segment 163 on a second side of the shaft 161, opposite said first side. The proximal end of the actuator rod 110 of the manual actuator 105 is assembled secured to the first segment 162 of the lever 160, such that a movement of said manual actuator 105 moves the lever 160 and vice versa. The controllable actuator also comprises operating means 170 configured to act on said lever 160 from the second segment 163 for moving said lever 160 between the first rocking position and the second rocking position and vice versa. In the case of the embodiment herein described, the operating means 170 comprise two electromagnets 171 separated by an access space 172 which vertically coincides with the free space left by the C shape of the rocker lever 160. In that sense, each of the two ends of the second segment 163 of the lever 160 is operated by one of said electromagnets 171, leaving the access space 172 free, which allows accessing from above the anchoring point of the lower electric terminal 102 of the device 1. Each electromagnet 171 is further provided with a permanent magnet configured to maintain the position of said rocker lever 160 in the event of losing electrical power in said electromagnet 171.
The controllable actuator also comprises securing means 180 arranged in the first segment 162 of the lever 160 and securing said lever 160 to the second mobile terminal 154 of the vacuum interrupter 150. Therefore, in the first rocking position, the second terminal 154 is in the proximal position, and in the second rocking position in which the vacuum interrupter 150 is closed, the second terminal 154 is in the distal position in which the vacuum interrupter 150 is open. In the embodiment of the figures, the securing means 180 comprise a bushing 181 integral with the rocker lever 160 and provided with a central through hole 182 that the second terminal 154 passes through. Figures 7, 8, 9, and 10 show how the bushing 181 has lateral holes 183 with an ellipsoid shape. A pin 184 is arranged passing through the second terminal 154 and the bushing 181, to the lateral holes 183 thereof. Particularly, the pin 184 extends perpendicular to the second terminal 154 and parallel to the rocking shaft 161.
Figure 7 and Figure 8 are detailed side views of the device 1. To facilitate comprehension of the operation of the vacuum interrupter 150, the walls of said vacuum interrupter 150 and of the bottle 155 have been eliminated in said figures such that the internal elements are visible. Figure 7 corresponds to the device 1 with the rocker lever 160 in the first rocking position, whereby the second terminal 154 is in the proximal position, and the switch element 104 is closed. In contrast, in Figure 8, the rocker lever 160 is in the second rocking position, whereby the second terminal 154 is in the distal position, and the switch element 104 is open. The two electrical contacts 151 and 152 of the vacuum interrupter 150 can be seen in Figure 7 and 8, these contacts are actually arranged in a vacuum medium inside the bottle 155, but they are herein visible, because said bottle 155 has been eliminated in these figures. The first fixed terminal 153 is attached to a first fixed rod, which communicates with the interior of said bottle 155 and is attached to one of said electrical contacts 151. The second mobile terminal 154 is attached to a second mobile rod, which communicates with the interior of said bottle 155 and is attached to the other one of said electrical contacts 152. Therefore, when the second terminal 154 is in the proximal position, like in Figure 7, the electrical contacts 151, 152 are in contact and the vacuum interrupter 150 is in the closed state, allowing the passage of electric current. In contrast, when the second terminal 154 is in the distal position, like in Figure 8, the electrical contacts 151, 152 are separated and the vacuum interrupter 150 is in the open state, impeding the passage of electric current therethrough.
Figure 9 and Figure 10 are detailed views of the attachment area between the second terminal 154 and the rocker lever 160. Figure 9 corresponds to the device 1 with the switch element 104 closed, whereas Figure 10 corresponds to the device 1 with the switch element open. In said figures, it can be observed how the controllable actuator further comprises locking means which are configured to lock the second terminal 154 in the proximal position when the lever 160 is in the first rocking position, which corresponds to the situation shown in Figure 9. Particularly, said locking means comprise a mobile part 190 with a body 191 provided with a latch 192 on a first side of the body 191, which has been depicted on the right side in the figures. The mobile part 190 is movably assembled along a straight line which is perpendicular to the second terminal 154 and to the rocking shaft 161, and in the figures this straight line corresponds to a horizontal straight line. Figure 9 shows the mobile part 190 in a locking position, and Figure 10 shows it in a release position. The mobile part 190 is movable between both positions. Likewise, the mobile part 190 is attached to a spring 196 on a second side of the body 191 opposite the first side of the body, and in the figures this side corresponds to the left side. A locking hole 193 facing the latch 192 in the first rocking position shown in Figure 9 is provided in the bushing 181 of the securing means 180. In the situation shown in said figure, the latch 192 is introduced into the locking hole 193. Figure 9 depicts the tip of the latch 192 and the locking hole 193 by means of discontinuous lines, given that they would otherwise be concealed in the detailed side view. Likewise, in Figure 9 the spring 196 is in a working position which, for the case of the first embodiment, corresponds to a compressed position. In contrast, in the situation shown in Figure 10, in which the lever 160 is in the second rocking position and the mobile part 190 is in the release position, the latch 192 is removed from the locking hole 193, and the spring 196 is in a standby position.
Figures 9 and 10 show that the mobile part 190 further comprises a spring rod 198 and a flange 199. The spring rod 198 is attached to the body 191 at its first end, depicted on the right, and to the flange 199 at its second end, depicted on the left. Therefore, the spring 196 is arranged around the spring rod 198, between the flange 199 and the body 191 of the mobile part 190. Furthermore, for the first embodiment, the mobile part 190 is arranged inside a box-shaped guide structure 120. The walls of said guide structure 120 appear in as a cutaway section in Figures 9 and 10. Inside said guide structure 120, guiding stops 197 are shaped as internal walls perpendicular to the direction of movement of the mobile part 190. These guiding stops 197 limit the movement of the mobile part 190 along the horizontal straight line perpendicular to the second terminal 154, impeding lateral movements. The guiding stops 197 close to the spring 196 further serve to compress the spring 196 between said guiding stops 197 and the flange 199, when said spring 196 is in the working position shown in Figure 9.
It can be seen in Figures 9 and 10 that the body 191 of the mobile part 190 further comprises an upper pushing portion 194 in the form of a ramp that ascends towards said second terminal 154, on the right in the figures. Moreover, the rocker lever 160 is provided with a lower pushing portion 195 in the form of a ramp complementary to the upper pushing portion 194 of the mobile part. Figure 10 shows that, in the second rocking position of the lever 160, the lower pushing portion 195 of the lever 160 is removed from the upper pushing portion 194 of the mobile part 190. In this situation, the spring 196 tends to expand to its standby position, driving the mobile part 190 and removing the latch 192 from the locking hole 193, as can be seen in Figure 10. When the lever 160 moves from the second rocking position shown in Figure 10 to the first rocking position shown in Figure 9, the lower pushing portion 195 contacts the upper pushing portion 194 and starts to push it. The shape of the ramps results in the presence of a horizontal component of the driving force going towards the second terminal 154, depicted on the right in the figures. The mobile part 190 is thereby driven to the locking position in which the latch 192 is introduced into the locking hole, as shown in Figure 9. When the device 1 is in this position, an eventual pushing of the second terminal 154 in the vertical direction will be blocked due to the interaction of the latch 192 with the lower wall of the locking hole 193, thereby producing a secure closure. In contrast, a movement performed on the rocker lever 160, for example, due to the actuation of the electromagnets 171 or the manual actuator 105, separates the lower pushing portion 195 attached to the lever 160 from the upper pushing portion 194 of the mobile part, and the spring 196 itself pushes the mobile part 190 towards the position shown in Figure 10. Therefore, the locking only affects the movements initiated by the vertical movement of the second terminal.
Other embodiments of the safety device 1 which share many of the features of the first embodiment described above are described below. Therefore, only the different elements will be described hereinafter.
In a second embodiment not shown in the figures, the device 1 further comprises a second toroidal current transformer configured to electrically power said control module 107 and said electromagnets 171.
In a third embodiment, the operational parameters comprise an electric current measurement in the branch, and the predetermined condition corresponds to the situation, in which said electric current measurement exceeds a threshold current without taking into account the time by which said threshold is exceeded.
In a fourth embodiment, the operational parameter further comprises a temperature measurement.
In a fifth embodiment, said operational parameter further comprises a voltage measurement. Still other embodiments use an operational parameter comprising current, voltage, and temperature measurements.
In a sixth embodiment, the control module 107 is further configured to perform a resetting, which comprises acting on said switch element 104, in order to move said switch element 104 from said open state to said closed state. The control module 107 starts the resetting when a predetermined resetting time has elapsed since said disabling, which is a value that can range between 5 and 180 seconds. Furthermore, the control module 107 is configured to carry out up to 5 retries if a disabling takes place immediately after said resetting.
In a seventh embodiment, the control module 107 further comprises a transmitter and a receiver configured to send operational parameters and for receiving commands. The commands comprise orders for configuration, for starting the disabling, for starting the resetting. In some embodiments, the command for starting the resetting includes the predetermined values of retries. Some examples of orders for configuration are modification of the predetermined condition, modification of the predetermined resetting time, or modification of the number of retries.

Claims

An electrical safety device (1) configured to be installed in a three-pole fuse base (2), comprising two terminals (101, 102) between which there is defined an electrical branch, said branch being provided with a fuse (103) configured to cut off the passage of electric current in said branch in the case of blowing;
wherein said device (1) further comprises:
- a switch element (104), provided in said branch and connected in series with said fuse (103), said switch element (104) having a closed state, in which it allows the passage of electric current, and an open state, in which it impedes the passage of electric current;

- a manual actuator (105), configured to move said switch element (104) from said closed state to said open state and vice versa;

- measuring means (106), configured to measure at least one operational parameter of said safety device (1); and

- a control module (107), configured to perform a disabling in the event that said at least one operational parameter meets a predetermined condition, wherein said disabling comprises acting on said switch element (104), in order to move said switch element (104) from said closed state to said open state;

characterized in that said switch element (104) comprises a vacuum interrupter (150) of the type comprising:
- a bottle (155), in which two electrical contacts (151, 152) are provided arranged in a vacuum medium;

- a first fixed terminal (153), attached to a first fixed rod, which communicates with the interior of said bottle (155) and is attached to one of said electrical contacts (151, 152);

- a second mobile terminal (154), attached to a second mobile rod, which communicates with the interior of said bottle (155) and is attached to the other one of said electrical contacts (151, 152);

wherein said second terminal (154) is movable in a direction perpendicular to said bottle (155) between a proximal position, in which said electrical contacts (151, 152) are in contact and said vacuum interrupter (150) is in said closed state, and a distal position, in which said electrical contacts (151, 152) are separated and said vacuum interrupter (150) is in said open state;

said device (1) further comprising a controllable actuator configured to move said second terminal (154) from said proximal position to said distal position or vice versa; wherein said control module (107) is configured to act on said switch element (104) by means of said controllable actuator; said controllable actuator comprising:
- a rocker lever (160), configured to rock about a rocking shaft (161) between a first rocking position and a second rocking position, said lever (160) having a first segment (162) on a first side of the shaft (161) and a second segment (163) on a second side of the shaft (161), opposite said first side;

- operating means (170), configured to act on said lever (160) from said second segment (163) for moving said lever (160) between said first rocking position and said second rocking position and vice versa;

- securing means (180), arranged in said first segment (162) and configured to secure said lever (160) to said second mobile terminal (154), such that in said first rocking position, said second terminal (154) is in said proximal position, and in said second rocking position, said second terminal (154) is in said distal position; and

- locking means, configured to lock said second terminal (154) in said proximal position when said lever (160) is in said first rocking position.
The device (1) according to claim 1, characterized in that said control module (107) is further configured to perform a resetting, which comprises acting on said switch element (104), in order to move said switch element (104) from said open state to said closed state.
The device (1) according to claim 2, characterized in that said control module (107) is further configured to start said resetting when a predetermined resetting time has elapsed since said disabling.
The device (1) according to any one of claims 2 or 3, characterized in that said control module (107) is further configured to retry at least once if a disabling takes place immediately after said resetting, the total number of retries preferably being limited to a predetermined value of retries.
The device (1) according to any one of claims 1 to 4, characterized in that said operational parameters comprise an electric current measurement in said branch, and said predetermined condition comprises at least one of the conditions where:
- said electric current measurement exceeds a threshold current; and

- said electric current measurement exceeds a threshold current during a threshold time.
The device (1) according to claim 5, characterized in that said measuring means (106) comprise a first toroidal current transformer, arranged surrounding an electrical conductor of said branch.
The device (1) according to any one of claims 1 to 6, characterized in that it further comprises a second toroidal current transformer, configured to electrically power said control module (107).
The device (1) according to any one of claims 1 to 7, characterized in that said operational parameters further comprise at least one of:
- a temperature measurement;

- a current measurement; and

- a voltage measurement.
The device (1) according to any one of claims 1 to 8, characterized in that said control module (107) further comprises remote connection means configured to at least one of:
- sending said operational parameters; and

- receiving commands.
The device (1) according to claim 9, characterized in that said commands comprise at least one of:
- a configuration command;

- a command for starting said disabling; and

- a command for starting said resetting;
wherein said command for starting said resetting preferably comprises said predetermined value of retries.
The device (1) according to claim 10, characterized in that said configuration command comprises at least one of:
- a command for modifying said predetermined condition;

- a command for modifying said predetermined resetting time; and

- a command for modifying said predetermined value of resetting retries.
The device (1) according to any one of claims 1 to 11, characterized in that said operating means (170) comprise at least one electromagnet (171), preferably two electromagnets (171) separated by an access space (172).
The device (1) according to claim 12, characterized in that each of said at least one electromagnet (171) is further provided with a permanent magnet, configured to maintain the position of said rocker lever (160) in the event of losing electrical power in said electromagnet (171).
The device (1) according to any one of claims 1 to 13, characterized in that said manual actuator (105) comprises:
- an actuator rod (110) arranged in a parallel direction with respect to said second mobile terminal (154) of said vacuum interrupter (150) and movable in said parallel direction, having a distal end relative to said vacuum interrupter (150) and a proximal end relative to said vacuum interrupter (150);

- a push button (111) secured to said actuator rod (110) at said distal end;
said proximal end being assembled secured to said first segment (162) of said rocker lever (160), such that a movement of said manual actuator (105) moves said lever (160) and vice versa.
The device (1) according to any one of claims 1 to 14, characterized in that said securing means (180) comprise:
- a bushing (181), integral with said rocker lever (160), provided with a central through hole (182) which said second terminal (154) passes through and with lateral holes (183); and

- a pin (184), arranged passing through said second terminal (154) and extending perpendicular thereto and parallel to said rocking shaft (161), passing through said lateral holes (183).
The device (1) according to claim 15, characterized in that said locking means comprise:
- a mobile part (190) comprising a body (191) provided with a latch (192) on a first side of the body, said mobile part (190) being movably arranged along a straight line which is perpendicular to said second terminal (154) and to said rocking shaft (161), between a locking position and a release position, or vice versa;

- a spring (196) attached to said mobile part (190) on a second side of the body opposite said first side of the body; and

- a locking hole (193) provided in said bushing (181) and facing said latch (192) in said first rocking position;

said locking means configured such that, in said first rocking position, when said mobile part (190) is in said locking position, said latch (192) is introduced into said locking hole (193), and said spring (196) is in a working position; and such that in said release position, said latch (192) is removed from said locking hole (193), and said spring (196) is in a standby position;

wherein said body (191) further comprises an upper pushing portion (194) in the form of a ramp that ascends towards said second terminal (154), and wherein said rocker lever (160) is provided with a lower pushing portion (195) in the form of a ramp complementary to said upper pushing portion (194) configured so that, in said second rocking position, said lower pushing portion (195) is removed from said upper pushing portion (194) and when said lever (160) moves from said second rocking position to said first rocking position, said lower pushing portion (195) pushes said upper pushing portion (194), driving said mobile part (190) to said locking position.
The device (1) according to claim 16, characterized in that said mobile part (190) further comprises:
- a spring rod (198) having a first end attached to said body (191) on said second side of the body, and a second end opposite said first end; and

- a flange (199) attached to said spring rod (198) at said second end;

said spring (196) being arranged around said spring rod (198), between said flange (199) and said body (191);

said device (1) further comprising guiding stops (197) arranged for limiting the movement of said mobile part (190) along said straight line; wherein, in said working position, said spring (196) is compressed between said flange and said guiding stops (197).
The device (1) according to any one of claims 1 to 17, characterized in that said vacuum interrupter (150) is arranged vertically, such that said second mobile terminal (154) is arranged so as to be movable in the vertical direction, and wherein said fuse (103) is arranged above said vacuum interrupter (150).
A three-pole fuse base (2) provided with at least one electrical safety device (1) according to any one of claims 1 to 18.