The present invention relates to a device for monitoring the position of a movable portion of a switching electrical apparatus. The movable portion is for example the lever of a circuit breaker, for example a mini circuit breaker. The invention also relates to a board that is capable of receiving a plurality of items of switching electrical apparatus such as circuit breakers furnished with a monitoring device of the invention.
Known from U.S. Pat. No. 4,706,073 is a circuit breaker furnished with an alarm circuit actuated in the event of a current overload. A permanent magnet is mounted on the lever of the circuit breaker while a sensor of the Hall effect type is designed to measure the variation of magnetic flux during the change of position of the lever. When there is a trip on an electrical fault, a movement of the permanent magnet causes a variation of magnetic flux sensed by the Hall effect sensor. According to this variation, a detector is capable of generating an output signal representative of an alarm.
In this type of device, the Hall effect sensor may easily be subjected to interference and outside influences when another magnet is brought close to the sensor. The variation of the magnetic flux thus generated may cause inadvertent tripping actions of the alarm when the lever of the circuit breaker is not in the tripped position. In addition, it requires the installation of costly and complex electronic means to measure the variation of the magnetic flux. The installation of several devices of this type in order to detect the state of several circuit breakers present on one and the same electrical circuit board is therefore not very advantageous.
The object of the invention is to propose a device for monitoring the position of a movable portion of a circuit breaker that is very precise, not very sensitive to outside magnetic fields and which may be used in large numbers to monitor in a simple and low-cost manner a plurality of circuit breakers on an electrical circuit board.
This object is achieved by a device for monitoring the position of a movable portion mounted on a casing of a switching electrical apparatus, the said movable portion being able to adopt at least two determined positions, the said device comprising:
characterized in that
The device according to the invention is particularly precise because the method of actuating the microswitch requires the presence of the permanent magnet in a determined position. If the permanent magnet is not in a precise position, the microswitch does not switch. The device according to the invention is therefore less prone to interference and does not risk switching inadvertently.
According to a variant embodiment of the invention, the permanent magnet is movable and set in motion by the movable portion and the receiver element is mounted on the casing of the switching electrical apparatus. The permanent magnet is for example supported by the movable portion.
According to the invention, the device comprises a fixed permanent magnet having field lines forcing the movable element to adopt a state. The change of position of the movable portion causes a change of direction of the magnetic field lines created by the said fixed permanent magnet and movable permanent magnet in the vicinity of the movable element, causing it to change state.
According to another variant embodiment of the invention, the permanent magnet is mounted on the casing of the switching electrical apparatus and the receiver element is set in motion by the movable portion. The receiver element is for example supported by the movable portion.
According to another variant embodiment of the invention, the device comprises a movable part forming a mask set in motion by the movable portion and capable of interrupting the magnetic effect produced by the permanent magnet on the microswitch when the movable portion is in one of its at least two positions.
According to the invention, the movable portion of the switching electrical apparatus may adopt three positions, two extreme positions in each of which at least one receiver element is commanded by the permanent magnet to establish or interrupt an electromagnetic coupling with the reader and an intermediate position in which the permanent magnet does not command the receiver element.
According to a particular feature, the microswitch is for example mounted in series with an antenna of the receiver element. In the closed state, the microswitch allows the establishment of the electromagnetic coupling between the reader and the receiver element.
According to another particular feature, the microswitch is for example mounted in parallel relative to an antenna of the receiver element. In the closed state, the microswitch makes it possible to short circuit the antenna and hence interrupt the electromagnetic coupling between the reader and the receiver element.
According to another particular feature, the receiver element is for example an RFID electronic tag positioned on the electrical apparatus. The reader is for example a station for reading this type of tag.
According to another particular feature, the movable portion is for example a pivot-action lever.
According to the invention, the monitoring device may be in the form of an adaptable independent module on a switching electrical apparatus.
The monitoring device is particularly suitable to be used on a switching electrical apparatus such as a circuit breaker and more particularly a mini circuit breaker.
The monitoring device may in particular be applied on each of the circuit breakers of an electrical circuit board. On the electrical circuit board, the reader may for example be common to all the items of switching electrical apparatus present.
Other features and advantages will appear in the following detailed description with reference to an embodiment given as an example and represented by the appended drawings in which:
The device according to the invention is applied to monitor the position of the movable portion of a switching electrical apparatus.
The switching electrical apparatus is more particularly an apparatus of disconnection such as for example a switch, a fuse-holder or a circuit breaker 1, more particularly a mini circuit breaker. In a known manner, a circuit breaker 1 comprises a casing 10 on which is mounted the movable portion consisting of a pivoting or rotary lever 11. The lever 11 may be set in motion between at least two positions, an ON (M) position and an OFF (A) position. The movement between the two positions ON (M) and OFF (A) may be carried out in an intentional manner by a user or in an automatic manner when an electrical fault such as a short circuit is detected. Certain circuit breakers 1′ may be provided with three positions, with an intermediate position (S) of the lever situated half-way between the ON (M) position and the OFF (A) position in order to signal the electrical fault or indicate the fusing of the contacts (
In
The monitoring device according to the invention comprises a reader consisting of a station 4 for transmitting/receiving electromagnetic waves. In a known manner, such a station 4 comprises an antenna 40 suitable for transmitting/receiving electromagnetic waves in a determined zone of action. Such a station 4 also comprises a radio frequency transmit/receive device transmitting, at a determined carrier frequency, an electronic processor unit and a memory associated with the processor unit. For reasons of simplification, these known elements are not represented in the figures.
The device according to the invention also comprises a receiver element 5 such as an electronic tag comprising its own antenna 50. Such a tag also comprises a radio frequency transmit/receive device, and an electronic processor unit and a memory for storing information on an electronic chip 51. Depending on its type, active or passive, the tag may also comprise its own power source.
In a known manner, an antenna 40, 50 is formed by an inductor optionally associated with a resistor and a capacitor in order to match the impedance of the antenna and tune the desired carrier frequency. The antenna of the receiver element may be of the dipole type or consist of a coil of copper wire (
The device of the invention operates according to the RFID technology. In the RFID technology, when an electronic tag such as the receiver element 5 is in the field of action of the station 4 and the station 4 transmits an electromagnetic signal, there is electromagnetic coupling between the tag and the station 5, the antenna 40 of the station 4 and the antenna 50 of the tag being able to be considered to be the primary and the secondary of a transformer. The electronic tag is supplied by the “carrier” transmitted from the antenna 40 of the station 4 as soon as it arrives within the limits of range of the said station 4. The energy captured by the antenna 50 of the tag is transformed into electric energy and supplies the internal electronic circuits mounted on the chip 51 of the tag. The tag responds to the signal transmitted by the station 4 and a dialogue may be established, the information being interchanged by amplitude or phase modulation on the carrier frequency. Each tag usually stores a unique identifier which it transmits to the station 4 in order to allow it to be recognized by the station 4.
The value of the frequency of the transmission carrier may be chosen in a zone called low frequencies (for example 125 KHz) or preferably high frequencies (for example 13.56 MHz) or even Ultra High Frequencies (900 MHz and 2.45 GHz). In these two cases, the system operates in inductive coupling in a near field, that is to say usually with a range of the order of from a few centimetres to a few tens of centimetres depending on the available energy.
According to the invention, with reference to
According to the invention, the receiver element 5 is commanded by a microswitch 2 mounted in series (
According to the invention, the microswitch 2 is controlled by magnetic effect. It is for example a microswitch 2 sensitive to the orientation of the field lines L of a magnetic field generated by a magnetic actuator. This type of microswitch is for example manufactured in MEMS (for Micro-Electro-Mechanical System) technology.
An exemplary configuration of a microswitch 2 sensitive to the orientation of the field lines L is represented in
A microswitch 2 sensitive to the orientation of the field lines L comprises a deformable ferromagnetic movable membrane 20 able to be actuated in rotation about an axis of rotation (R) by the magnetic actuator. The membrane 20 is for example Iron-Nickel.
The membrane 20 has a longitudinal axis (A) and is connected, at one of its ends, by means of connecting arms 22a, 22b, to one or more anchor blocks 23 secured to a substrate 3. The substrate 3 is for example that on which the electronic chip 51 of the receiver element 5 is mounted. The membrane 20 is capable of pivoting relative to the substrate 3 along its axis (R) of rotation perpendicular to its longitudinal axis (A). The connecting arms 22a, 22b form an elastic connection between the membrane 20 and the anchor block 23 and are made to bend when the membrane 20 pivots.
At its distal end relative to its axis of rotation, the membrane supports a movable contact 21. By pivoting, the membrane 20 may adopt at least two determined states, an open state (
One of the methods of actuating the membrane 20 consists in applying a magnetic field created by a permanent magnet 60. The ferromagnetic membrane 20 moves between its two states while aligning itself on the field lines L of the magnetic field generated by the permanent magnet 60. With reference to
According to the invention, the permanent magnet 60 moves at the same time as the lever 11. The permanent magnet 60 is, for example, mounted directly on the lever 11 of the circuit breaker 1 or, according to a variant, it may also be simply fixed mechanically to the lever, by, for example, being mounted on a movable part actuated in vertical translation each time the lever 11 moves. Depending on the position of the lever 11, the membrane 20 of the microswitch 2 is either under the magnetic influence of the permanent movable magnet 60 or not. When the lever 11 is in the ON (M) position (
According to a variant embodiment not shown, the arrangement between the permanent magnet 60 and the receiver element 5 may be inverted, the receiver element 5 becoming movable, mechanically secured to the lever 11 and the permanent magnet 60 becoming fixed. The movement of the lever 11 brings the receiver element 5 opposite the permanent magnet 60, causing the switching of the microswitch 2 under the influence of the magnetic field created by the permanent magnet 60. The operation of this variant embodiment is identical to that described just above.
According to a variant embodiment shown in
According to another variant embodiment represented in
The principle of operation of the invention described above with reference to
According to this variant embodiment, in normal operation, whether the lever 11 is in the ON (M) position or in the OFF (A) position, the station 4 always receives a signal from one of the receiver elements 5a, 5b by electromagnetic coupling (
On each of the two receiver elements 5a, 5b, the microswitch 2 is mounted in series with the antenna 50 but mounting in parallel may be envisaged. However, in this latter case, the station 4 receives no signal when the lever 11 is in the ON or OFF position and receives a signal from both receiver elements 5a, 5b when the lever 11 is in the intermediate position.
Instead of two receiver elements 5a, 5b and one permanent magnet 60, a single receiver element secured to the lever and two permanent magnets each mounted on the casing 10 opposite both of the two positions, ON and OFF, of the lever 11 may be employed. However, in this configuration, one and the same signal will be sent to the station 4 whether the lever 11 is in the ON or OFF position. By mounting the microswitch 2 in parallel relative to the antenna 50 of the receiver element, only one signal may be sent to the station when the lever 11 is in the intermediate position (S).
The monitoring device described above may be applied in each circuit breaker 1 of an electrical circuit board 8 comprising a plurality of circuit breakers 1. In this board 8 shown in
This board 8 comprises for example one or more rows of circuit breakers 1 each furnished with a lever 11 whose position is monitored thanks to a monitoring device according to the invention. Since a unique identifier is assigned to each receiver element 5 of a circuit breaker 1, the station 4 is capable, based on a processing means optionally using anticollision methods, of knowing the state of each lever 11 of the circuit breakers 1 mounted on the board 8. The processing means may be coupled to signalling members consisting of LEDs designed to indicate the state of each circuit breaker 1 of the board.
According to the invention, each receiver element 5 may also store information relating to the circuit breaker 1 with which it is associated, such as for example the name of the electric circuit that it is responsible for commanding.
Each receiver element 5 may be accessible in read mode and optionally in write mode.
The monitoring device according to the invention is particularly easy to put in place and does not require fundamentally converting the switching electrical apparatus, which makes it possible to restrict the cost of its installation.
It is clearly understood that it is possible, without departing from the context of the invention, to imagine other variants and enhancements of detail and even to envisage the use of equivalent means.
Number | Date | Country | Kind |
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0651833 | May 2006 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/054650 | 5/14/2007 | WO | 00 | 11/19/2008 |