EP1724803B1

EP1724803B1 - Electronic device to be associated with an electrical apparatus

Info

Publication number: EP1724803B1
Application number: EP06425294A
Authority: EP
Inventors: Fabrizio Fabrizi; Marcello Re; Daniele Novati
Original assignee: BTicino SpA
Current assignee: BTicino SpA
Priority date: 2005-05-17
Filing date: 2006-05-03
Publication date: 2010-04-21
Anticipated expiration: 2026-05-03
Also published as: EP1724803A3; ATE465506T1; ITMI20050901A1; EP1724803A2; DE602006013747D1

Abstract

An electronic device (500) is described to be connected to an electrical installation and to be operatively associated with an electrical apparatus (100). The electronic device allows detecting an operative condition of the electric installation (for example, a failure) and generating a corresponding command signal based to which an operative condition of the electrical apparatus is changed. The electronic device is housed in an enclosure (501) independent of a further enclosure (107) of the electrical apparatus, and is provided with means for reversibly fixing the enclosure to the further enclosure.

Description

The present invention relates to an electronic device to be associated with an electrical apparatus, such as, by way of non-limiting example, a safety device.
Safety devices (such as, for example, automatic circuit-breakers, ground fault circuit interrupters, automatic ground fault circuit interrupters) fitted in an installation may cause inefficiencies if their action is ill-timed. Tripping is frequent phenomenon, i.e. the ill-timed opening of ground fault interrupters, due to ground leakage currents either resulting from transient surges on the power line (direct or indirect lightning striking) or temporary failure of the insulation.
If the installation place is not guarded, the safety device is not manually closed after it has tripped in a ill-timed manner, thereby severe inefficiency may occur, such as: failure of alarm operation, safety systems, pump systems or switching off of freezers with deterioration of the food contained therein.
These problems have been addressed and partially solved by modules to be associated with the safety devices, which are able to reset and then automatically close the devices at a preset time after tripping. Particularly, a known reset module comprises an inner kinematism acting on the manual lever of the safety device and a thermal actuator acting on the kinematism when the safety device has tripped, in order that the kinematism actuates the resetting.
Reset modules are known comprising an electronic device therein, which is suitable to detect the installation failure and lock out the reset module by signalling this locked-out condition to the outside. In this locked-out condition, the automatic resetting of the safety device is prevented of an actual installation failure.
A drawback with the conventional resetting modules being provided with the electronic device is that they cannot be adapted to the varying typologies of safety devices to which they have to be associated.
Document WO 2004/047137 A (D1) describes a release device whose housing can be arranged in an adjacent manner to the switch housing of a motor protection switch.
The object of the present invention is to allow monitoring the condition of the installation which does not suffer from the above-cited prior art drawback.
The object of the present invention is achieved by an electronic apparatus such as described in the annexed claim 1. Preferred embodiments of said apparatus are described in the dependent claims 2 to 20. The object of the present invention is also an electrical assembly such as defined in the dependent claim 21.
In order to better understand the present invention and appreciate the advantages thereof, some exemplary embodiments thereof will be described below, with reference to the annexed drawings, in which:

Fig. 1 shows a perspective view of a control device assembled to a safety device, according to a preferred embodiment of the invention;
Fig. 2 is a perspective view of an example of said safety device;
Fig. 3 is a schematic view of a circuit board of said control device and the main blocks of said safety device;
Fig. 4 schematically shows several electromechanical parts of said control device;
Fig. 5 is a perspective view of an enclosure for said control device;

With reference to the annexed figures, in which similar or identical components are designated with the same numerals, an electrical assembly 300 will be described in accordance with an exemplary embodiment of the invention.
Fig. 1 shows the electrical assembly 300, in the assembled configuration, comprising an electrical device 100 that is operatively associated with a control electronic device 500.
The electrical apparatus 100 is preferably a safety electrical device, such as of a conventional type. As illustrated in the diagram from Fig. 3, the safety device 100 is provided with input terminals Li and Ni (such as a phase terminal and a neutral one) for connection to a power network NW and output terminals Lo and No for connecting the safety device to an external electrical circuit which is outlined in the figure as a load LD (such as a household electrical installation).
The safety device 100 is such as to adopt a closed state in which the load LD is connected to the power network NW and an open state in which the load LD is disconnected from the power network NW.
The safety device 100 can be, for example, one of the following conventional circuit breakers: automatic circuit-breaker, ground fault circuit interrupter, automatic ground fault circuit interrupter (such as a magneto-thermal ground fault interrupter). In Fig. 3 an automatic ground fault circuit interrupter has been outlined, which comprises a contact breaker 400 and an automatic circuit-breaker 600.
Referring back to Fig. 1 (which shows a ground fault circuit interrupter 100), the safety device 100 comprises a respective enclosure made of insulating material 107 and a first drive lever 112 (e.g., a handle) that can be manually displaced between two different positions to switch the safety device from the closed state to the opened state, and vice versa, in a manual manner. The insulating body 107 houses electro-mechanical means (not shown, as know per se) therein, which automatically cause the opening thereof with the consequent displacement of the first drive lever 112, following the detection of a failure in the load LD such as, for example, a ground leakage current or a short-circuit. Furthermore, this safety device 100 has on a side wall 107' thereof, in a manner known per se, an aperture 110 (seen only in the view from Fig. 2) in which a pivot can be inserted from the outside such as to be coupled with a coupling and releasing mechanism (not shown, as being conventional) housed in the enclosure 107 to cause the switching of the device 100. On the side wall 107' there are also formed apertures 115 for mounting to the control device 500.
An upper wall 102 and a lower wall 103 of the safety device 100 are provided with terminals 109 for further input Li and Ni and output Lo and No phase and neutral conductors that are connected to the control device 500.
With reference to Fig. 3, 4, and 5 , the control electronic device 500 comprises an insulating enclosure body 501, such as including two portions to be fixed by means of screws or rivets (not shown), which engage within seats 502.
It should be noted that the control device 500 is a module separated from the safety device 100, since the enclosure 501 is independent from the enclosure 107 of the safety device 100. The enclosure 501 of the control device 500 is provided with reversible fixing means allowing the same to be coupled and uncoupled to/from the enclosure 107 of the safety device. These fixing means comprise, for example, clips 550 (Fig. 5) to be inserted in apertures 115 (Fig. 2) being formed in the enclosure body 107 of the safety device 100. One or more of said clips 550 is fixed to a respective support element 551 to be inserted in a seat of the enclosure 501 and to be fixed thereto by means of a respective screw.
As can be seen in Fig. 1, the enclosure 501 is provided with a first plurality of terminals 503 for connection with the phase Li and neutral Ni input conductors, which are taken from the safety device 100 and thus connect the control device to the power network NW.
Furthermore, the enclosure 501 is provided with a second plurality of terminals 503' for connection to the phase Lo and neutral Lo conductors, which output from the safety device 100 and thus connect the control device to the load LD. Advantageously, a terminal of the second plurality of terminals 503' is connected by means of a conductor PE to a safety circuit (i.e. the earth), if present. The terminals of the first plurality 503 can also be used to send suitable command signals to the reset module, if provided, which are transmitted by remote control units (by means of terminals C1 and C2 illustrated in Fig. 3), in order either to open and close the safety device 100 or monitor the load LD.
The control device 500 is capable of detecting an operative condition of the load LD and generate a corresponding command signal based on which an operative condition of the safety device can be changed. In greater detail, and in accordance with the embodiment in question, the control device 500 comprises control electronic means 50 (Fig. 3 and 4), which are connected to the load LD and being such that either a failure condition or normal condition of the load is detected, and in the former case, a command signal Sr is generated, which is provided on a corresponding power line.
Furthermore, the control device 500 is provided with actuating means, which are at least partially enclosed within said enclosure 501 and can be coupled to the safety device 100, which are intended to receive the command signal Sc and act on the safety device in order to change the operative condition thereof.
The control electronic means 50 will be considered first, which are shown in Fig. 3 and preferably provided on a printed circuit board that is completely housed within the enclosure 501. This circuit board 50 comprises a check electronic block 51 (MEAS) communicating with a central block or unit 52 (µC) managing the entire board 50 and, advantageously, a power supply device 53.
The power supply device 53 is connected to the input phase and neutral conductors Li and Ni to receive alternating current (such as, 50 Hz frequency) from the network NW and includes a rectifier circuit that converts it to direct current and provides the circuit board 50 with a suitable voltage value. Preferably, this power supply device 53 is provided with a safety transformer allowing the load LD to be suitably insulated from the power network NW. In other words, the isolating transformer allows preventing the circuit board 50 from placing the network NW and the load LD in contact with each other, i.e. transferring the voltages of the network to the load. This isolating transformer is particularly advantageous because, when the safety device 100 is opened, it prevents the network voltages from being transferred to the load of the circuit board thereby allowing maintenance operations to be carried out on the load in total safety.
Advantageously, a fuse FU is provided on the input phase conductor Li to protect the circuit board from high currents from the network NW, which may damage it.
The check block 51 and central unit 52 are connected to the output of the power supply device 53.
The check block 51, which can be provided with technologies known in the art, is connected to an output of the load LD (by means of the conductors Lo and No) and is capable of carrying out measurements of electrical parameters of the load LD.
The check block 51 is further capable of detecting whether the safety device 100 has turned to the open state, because it detects the lack of electric voltage on the load LD. When this situation occurs (the safety device 100 is open), the check circuit (driven by the central unit 52) starts one or more measurements on the load LD to evaluate whether it is experiencing an actual failure condition or if the safety device 100 has been opened due to a temporary cause (such as due to an ill-timed tripping of the safety device).
For example, the check block 51 is capable of carrying out a direct current measurement of the impedance between phase conductor Lo and neutral conductor No of the load LD. Advantageously, when the safety circuit is provided (grounding GND), the check block 51, by means of the conductor PE, can carry out (either alternatively or in addition to the above measurement) an alternating current measurement (at a suitable frequency) of impedance between the output phase and neutral conductors Lo and No and the safety circuit. Furthermore, the control device can carry out a measurement of the leakage current by applying a voltage, between the output phase Lo and output neutral No conductors and the safety circuit, respectively.
These measured values of the impedances or leakage current can be provided in the form of corresponding data to the central unit 52.
The central unit 52 (for example, an integrated microcontroller) receives these data and compares them with reference electrical parameters that have been previously stored therein. When the impedance values resulting from the comparison are consistent with a condition of failure, the central unit 52 activates the command signal Sc. Advantageously, the central unit 52 also acts as an interface with the user and is equipped with a communication port CP, such as of the serial type, for the remote monitoring of the load LD and exchange of information concerning the measurements that have been carried out.
According to a preferred embodiment of the invention, the check block 51 is also capable of carrying out a measurement of the maximum electrical voltage provided by the power network NW and sending corresponding data to the central unit 52 that provides to activate the command signal SC if the measured voltage exceeds a maximum reference value. This measurement of the maximum voltage is particularly useful for protecting single-phase users connected in three-phase installations, because in these installations the interruption of the neutral implies that an overvoltage exists between the phases and the neutral as a function of the type of single-phase loads that are distributed between the neutral and phases. The interruption of the neutral can be due to accidental causes (opening of the main switch pole, interruption of conduits, interruption of cable joints, or the like) and the resulting overvoltage is the cause of considerable damages to the electrical equipment.
Reference will be now made to the above-cited actuating means which, as stated above, are intended to receive the command signal Sc (activated by the central unit 52) and act on the safety device 100 to change the operative condition thereof. According to the particular example described herein, the actuating means comprise a release device to be mechanically connected to the safety device 100 such that the switching from the opened condition to the closed condition is inhibited when the command signal indicates that a failure condition of the load has been detected.
In greater detail, this release device comprises a first contact-breaker 54, an energizable coil actuator 55 (for brevity, the "release coil" herein below) and a rotating rocker body 56 (Fig. 3 and 4).
The first circuit-breaker 54 is preferably an electronic circuit-breaker (for example, a TRIAC) connected to the network NW and having an output connected (by means of a first contact 57) to the release coil 55. The first circuit-breaker 54 can be driven by means of the command signal Sc described above and, for example, is closed when said command signal is activated.
The release coil 55, when electrical current flows therethrough (i.e. when both the first circuit-breaker 54 and first contact 57 are closed), generates such a magnetic field that a rod-like element 58 cooperating with the rocker body 56 is translated.
As illustrated in Fig. 4, the rocker body 56 is free to perform limited rotations about a pivot 59 and supports a motion transmission element, such as particularly, a pin 60. This pin 60 projects outside the enclosure 501 of the control device 500 for insertion in the opening 110 (Fig. 2) of the safety device 100. The pin 60 is such as to be engaged with the release mechanism included in the enclosure 107 of the safety device 100, thereby causing the switching of the latter due to the rotation of the rocker body 56.
Preferably, the control device 500 further comprises a second drive lever 522 that can be rotated about a pivot 523 and held, when no further action has to be taken, in the closed position (Fig. 1) together with a helical spring wound on the pivot 523 and having ends 524 and 525. The end 524 of the spring is a part of a contact 61, which, when closed (i.e. the contact 61 being in the position of Fig. 4 and the safety device 100 being in the opened condition) connects an output terminal of the check block 51 to the output neutral conductor No, thereby allowing said measurements to be taken.
The second drive lever 522 is mechanically connected to the first drive lever 112 of the safety device 100, such as by means of a projecting element 530 of the second lever 522 which inserts within a side cavity of the first lever 112.
The control device 500 is advantageously provided with a front push-button PA that can be accessed from the outside, which allows the same to be opened/closed in order to deactivate/activate the action of the command signal Sc. Furthermore, different devices signalling the condition of the control device 500 can be provided. For example, the enclosure 501 of the control device 500 is provided with a first LED (Light Emitting Diode) 526 signalling a short-circuit and a second LED 527 signalling a ground failure. A sound signal device (to be activated by the central unit 52, similar to the LEDs 526 and 527) may also be provided, which warns the user about the presence of a permanent failure. This sound signal can be useful when the control device 500 is installed in a junction box located in a decentred area. The sound signal can be silenced by acting on the front push-button PA or eliminating the failure condition. The sound signal can be used to identify the failure occurring on the installation (i.e. according to the example, the load LD), by removing the plugs of the users or sectioning the parts of the installation until the failure area is identified, and the sound signal turns off. The central unit 52 is preferably capable of storing the failure signallings such that, even in case of temporary absence of voltage from the power network NW, the failure is signalled when the voltage is restored.
With reference to the operation of the electrical assembly 300, an initial condition will be considered in which the safety device is closed (drive lever 112, as in Fig. 1). In this case, the check block 51 of the control device 500 detects that the voltage is present on the load LD and arranges itself in a rest condition.
When the safety device 100 is opened (either by manual opening, opening due to an actual failure or ill-time opening), the check block 51 of the control device 500 does not detect the voltage on the load LD and activates, automatically and under the management of the central unit 52, the control of the condition of the load LD.
The check block 51 then carries out either all or some of the above measurements (impedances or leakage currents) to define the corresponding electrical parameters. These electrical parameters are then provided to the central unit 52 that (by running a pre-stored software) compares with reference values, which are set by the current standards, for example. This condition corresponds to Fig. 4, in which the second drive lever 522 is seen lowered and the contact 61 is closed.
If , following this comparison, the central unit 52 identifies one or more anomalous values in the electrical parameters, and believes that an actual failure has occurred, it activates the command signal Sc.
This command signal Sc closes the first electronic circuit-breaker 54. The central unit 51 can further activate the signalling devices listed above. When a user closes the safety device 100 by acting manually on the first drive lever 112, the mechanism inside the safety device 100 by means of the pin 60 causes the rotation of the rocker body 56 (arrow F1) which causes the first contact 57 to close.
In this condition, the release coil 55 is powered by the network NW, as both the first circuit-breaker 54 and first contact 57 are closed (see Fig. 3). The release coil 55 is rapidly powered such as to cause, by means of the rod-like element 58, the rotation of the rocker body 56 in the opposite direction.
This rotation of the rocker body 56 (arrow F2) moves the pin 60 such that the safety device 100 is rapidly re-opened, thereby preventing the latter from being manually closed and preventing that, in this attempt of closure (carried out in the presence of a failure) the power contacts (block 600) of the safety device close by causing a short-circuit current or ground failure to flow. In Fig. 3, the interaction between the release coil 55 and the contacts of the circuit-breaker 600 is symbolically schematized with an arrow F.
It should be noted that, according to a variant embodiment of the invention, alternatively to the safety device 100, the modular control device 500 can be associated with a reset module (for example of a known type) which is intended to reset the safety device.
It should be observed that using a control device 500 provided in the form of an independent module has the advantage that it can be structurally coupled with several safety devices or other types of electrical apparatuses (having a standardized shape). For example, with already installed electrical switchboards, due to the versatility of the inventive control device, the safety device can be implemented to the control device, with clear consequences on cost reduction. In addition, due to the modularity of the inventive control device, there is no need to modify and complicate either the structure of the known safety devices or the manufacturing techniques therefor.
As already stated in the above description, other relevant advantages relate to the use of the isolating transformer and the possibility of providing a maximum voltage protection. Furthermore, the following advantageous aspect are reported:

the measurement carried out on the installation (load LD) by means of the safety conductor PE allows using the control device 500 in phase-to-phase and phase-to-neutral systems;
the exclusion of the check concerning the ground failure current can be carried out simply by avoiding to connect the safety conductor PE;
the control device of the invention can be also used for the remote release function.

Obviously, to the electrical assembly according to the present invention, those skilled in the art, aiming at satisfying contingent and specific requirements, may carry out a number of modifications and variations, all being however contemplated within the scope of protection of the invention, such as defined in the annexed claims.

Claims

A control electronic device (500) to be connected to an external electrical circuit (LD) and to be operatively associated with an electrical apparatus (100), said device comprising first terminals (Li, Ni) to be connected to a power network (NW) of the device (500) and second terminals (Lo, No) to be connected to the electrical circuit (LD), the device allowing an operative condition of the electrical circuit to be detected and a corresponding command signal (Sc) to be generated based on which an operative condition of the electrical apparatus can be changed, said device being housed in an enclosure (501) independent of a further enclosure (107) of the electrical apparatus, and provided with means (550,551) for reversibly fixing said enclosure to the further enclosure,
said enclosure (501) including control electronic means (50) to be electrically connected to the electrical circuit (LD) in order to detect the operative condition thereof, and generate the command signal (Sc) when a failure condition has been detected,
characterized in that
said control electronic means (50) comprise:
- a check electronic block (51) to carry out measurements of electrical parameters of said electrical circuit (LD),

- a central electronic block (52) to compare data corresponding to said electrical parameters with reference electrical parameters and generate the command signal (Sc),
and in that
said check block (51) is capable of carrying out a measurement of the electric voltage being provided by the power network (NW) and the central electronic block (52) is capable of generating a command signal when the measured voltage exceeds a maximum reference value.
The device (500) according to claim 1, further comprising actuating means (54, 55, 56, 60), which are at least partially enclosed in said enclosure and can be coupled with the electrical apparatus, the actuating means being intended to receive the command signal and act on said electrical apparatus to change the operative condition thereof.
The device (500) according to claims 1, wherein said control electronic means (50) are connected between the first (Li, Ni) and second (Lo, No) terminals and include a power supply device (53) provided with a safety transformer to insulate the electric circuit (LD) from the power network (NW) .
The device (500) according to claim 3, wherein the power supply device (53) further includes a rectifier circuit to provide the control electronic means (50) with direct voltage.
The device (500) according to claim 1, wherein said electrical apparatus is a safety electronic device (100) including terminals being connected to a power network (NW) and such as to adopt a closed condition in which the electrical circuit is connected to the power network and an open condition in which the electrical circuit is disconnected from the power network.
The device(500) according to claim 2 and 5, wherein said actuating means include a release device (55, 58, 56, 60) to be mechanically connected to the safety device (100) to inhibit the manual switching of the same from the opened state to the closed state when said command signal (Sc) indicates that a failure condition of the electrical circuit has been detected.
The device (500) according to claim 1, wherein said electrical circuit (LD) is provided with at least one phase conductor (Lo), and a neutral conductor (No) and said check block (51) is such as to carry out a direct current measurement of the impedance between phase conductor and neutral conductor.
The device (500) according to claim 7, wherein said electrical circuit (LD) is further provided with a ground safety circuit (and) and the check block (51) is connected to the safety circuit such as to be able to carry out a direct current measurement of the impedance between said phase and neutral conductors and the ground circuit.
The device (500) according to claim 8, wherein the check block (51) is connected to the safety circuit such as to be able to carry out a measurement of the ground leakage current.
The device (500) according to claim 1, wherein the check block (51) is such as to carry out said measurements of the electrical parameters after the lack of electrical voltage applied by the power network to the electrical circuit has been detected,
The device (500) according to claim 1, wherein the electronic control means (50) are provided on a printed circuit board and the central electronic block (52) is an integrated microcontroller which operates based on a software.
The device (500) according to claim 6, wherein said release device includes:
- a circuit-breaker (54) to be driven by said command signal (Sc) in order to output an actuating signal, when it is closed,

- electromechanical actuating means (56) such as to displace a movable element (58) based on an electrical current associated with the actuating signal,

- a rocker body (56) to be rotated following the displacement of the movable element and such as to support a motion transmission element (60), said motion transmission element (60) expending outside this enclosure (501) to be engaged with a release mechanism included in the further enclosure (107) of the safety device, such as to cause the same to open.
The device (500) according to claim 1, wherein said enclosure (501) is made of an electrically insulating material and said fixing means include at least one clip (550) to be inserted in an aperture (115) being formed in said further enclosure (107) such as to allow the device to be mounted to said electrical apparatus.
The device (500) according to claim 5 , wherein the fixing means allow the control device to be assembled to the following types of safety devices: automatic circuit-breakers, ground fault circuit interrupters, automatic ground fault circuit interrupters.
The control device (500) according to at least one of the preceding claims, comprising a light or sound signal device being driven by said central unit to signal the presence of a failure on said electrical circuit (LD).
The control device (500) according to at least one of the preceding claims, wherein said central unit is such as to perform the function of user interface and comprises a preferably serial, communication port (CP) for monitoring the state of the electrical circuit (LD) and exchanging information concerning said electrical parameters.
An electrical assembly (300) comprising; an electrical apparatus (100) to be connected to a power network (NW) and an external electrical circuit (LD); a control electronic device (500) to be connected to the external electrical circuit (LD) and to be operatively associated with the electrical apparatus (100),
characterized in that said electrical apparatus and said control electronic device are provided according to at least one of the preceding claims.