EP3886128B1 - Electrical switching device - Google Patents
Electrical switching device Download PDFInfo
- Publication number
- EP3886128B1 EP3886128B1 EP20165095.9A EP20165095A EP3886128B1 EP 3886128 B1 EP3886128 B1 EP 3886128B1 EP 20165095 A EP20165095 A EP 20165095A EP 3886128 B1 EP3886128 B1 EP 3886128B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- mobile member
- switching device
- acceleration
- sensor
- electrical switching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000001133 acceleration Effects 0.000 claims description 69
- 238000006073 displacement reaction Methods 0.000 claims description 27
- 238000012545 processing Methods 0.000 claims description 21
- 238000005259 measurement Methods 0.000 claims description 4
- 239000003990 capacitor Substances 0.000 description 5
- 244000145845 chattering Species 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 230000005294 ferromagnetic effect Effects 0.000 description 3
- 230000002950 deficient Effects 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 230000005291 magnetic effect Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/0015—Means for testing or for inspecting contacts, e.g. wear indicator
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
- H01H11/0062—Testing or measuring non-electrical properties of switches, e.g. contact velocity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/04—Means for indicating condition of the switching device
- H01H2071/044—Monitoring, detection or measuring systems to establish the end of life of the switching device, can also contain other on-line monitoring systems, e.g. for detecting mechanical failures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2300/00—Orthogonal indexing scheme relating to electric switches, relays, selectors or emergency protective devices covered by H01H
- H01H2300/052—Controlling, signalling or testing correct functioning of a switch
Definitions
- the present invention relates to a device for switching electrical currents and/or voltages, typically for power switching, such as a relay or a circuit breaker.
- These devices typically comprise a stationary member, a mobile member that is displaceable between a closed position in which a contact pad of the mobile member is in electrically conductive contact with the stationary member, and an open position in which there is no electrically conductive contact, and an actuator for displacing the mobile member.
- the mobile member When in such a device the mobile member is moved into or out of the closed position while a voltage is applied to the mobile and stationary members, an arc may form when the distance between the members is small enough but not zero, deteriorating the quality of the contacting surfaces of the mobile and stationary members. This may cause the surfaces to adhere to each other. Initially, weak adhesion may merely delay the switching operation, but if finally adhesion becomes too strong for the actuator to overcome, switching is prevented. Similarly, mechanical wear of the mobile member and its bearings may first merely delay the switching operation and finally prevent it altogether. Mechanical breakage might even cause the switching movement to become faster than normal, if the inertia of moving components is reduced.
- EP 2 290 666 A1 discloses a switching device in which an end position switch or a light barrier is used for controlling whether an end position is properly reached. If it isn't reached, the device is defective and must be replaced, but the defect cannot be predicted before it actually occurs.
- WO 2018/108833 A1 discloses an electrical switching device in which life expectancy of a switching device is predicted based on its chattering behaviour, derived from current flowing through a Reed contact or through the solenoid driving the switching movement. This is a rather indirect way of judging life expectancy, since arc formation is not necessarily accompanied by chattering, but if arcs are formed, chattering will accelerate wear of contact surfaces. Therefore, if it is attempted to minimize downtime of a system by replacing switching devices thereof when these show suspicious chattering, there is a considerable probability that a switching device is replaced prematurely. Although such a replacement can be planned, and downtime for replacement can be kept short, it still causes an interruption of operation of the system in which the switching device is used, and potentially unnecessary cost.
- US 2019/0018065 A1 discloses a switching device in which an acceleration sensor is provided on a mobile member of the acceleration device for measuring acceleration thereof when the mobile member is being switched between closed and open positions, and wear of the switching device is detected based on output of the acceleration sensor.
- the object of the present invention is to improve sensitivity of the acceleration sensor.
- the acceleration sensor is capable of detecting any irregularity of movement of the displaceable member, regardless of its cause.
- the acceleration detected by the acceleration sensor is amplified.
- the sensor and the contact pad can be rotatable by a same axis, the radius of the acceleration sensor being longer than that of the contact pad.
- the actuator can be of any type, but typically comprises a solenoid adapted to interact magnetically with the mobile member.
- a solenoid adapted to interact magnetically with the mobile member.
- most of the energy driving a displacement of the mobile member may be provided by a spring, the magnetic interaction of the solenoid merely serving to unlock the mobile member so as to enable its displacement by the spring.
- the acceleration sensor can be a micromechanical sensor. Such sensors are rugged and suitable for use in any orientation relative to the gravity vector. They are in widespread use e.g. for controlling airbags in motor vehicles and are therefore available at low cost.
- the acceleration sensor can be fixedly integrated into the mobile member, in order to follow its displacement as closely as possible.
- the acceleration sensor might be resiliently coupled to the mobile member. This can be useful in particular if the duration of the displacement of the displaceable member is known and constant; in that case the resonance period of the sensor mount can be tuned to the duration of the displacement so that any variation of that duration has a noticeable effect on the vibration of the sensor caused by the displacement.
- the bandwidth of the acceleration sensor should be high enough to obtain at least one acceleration measurement, i.e. higher than the inverse of the duration of a displacement of the mobile member between the open and closed positions. Preferably, it should be high enough to allow taking a plurality of acceleration measurements in the course of a displacement of the mobile member.
- the switching device may be associated to a processing unit which is adapted, e.g. programmed, to derive a judgment on the integrity of the switching device from current acceleration data obtained in relation to a current displacement of the mobile member between the first and second positions driven by the actuator.
- the switching device and the processing unit can be associated in the form of an assembly for joint installation.
- the processing unit can be remote from the switching device, communicating with the acceleration sensor via a digital network such as a LAN or the Internet.
- the processing unit can be adapted to derive the judgment on the integrity of the switching device from a comparison of said current acceleration data with standard acceleration data.
- Such standard acceleration data can be predetermined data, which may be provided by the manufacturer, for a specific type of switching device.
- the processing unit is adapted to derive the standard acceleration data (or to update earlier standard data such as those provided by the manufacturer as mentioned above) based on acceleration data obtained in relation to earlier displacements of said mobile member.
- the standard acceleration data or to update earlier standard data such as those provided by the manufacturer as mentioned above
- the processing unit is adapted to derive the standard acceleration data (or to update earlier standard data such as those provided by the manufacturer as mentioned above) based on acceleration data obtained in relation to earlier displacements of said mobile member.
- the standard acceleration data or to update earlier standard data such as those provided by the manufacturer as mentioned above
- the current acceleration data that are provided by the acceleration sensor in relation to a current switching movement should cover a time interval before and after an instant in which the mobile member reaches the second position.
- data obtained before that instant are indicative of the condition of the mobile member in its first position, such as possible sticking, and of movement from the first position to the second, whereas data obtained after reaching the second position allow to draw conclusions on the condition of the mobile member in the second position.
- the switching device may comprise a network interface for outputting data of the acceleration sensor obtained in relation to a displacement of the mobile member, or data derived from these, e.g. by a local processing unit.
- Fig. 1 is a highly schematic representation of components of a relay.
- the relay has a mobile member 1, which is displaceable between an closed position in which a contact pad 2 of mobile member 1 is in electrically conductive contact with a stationary member 3, allowing a current to flow between terminals 4, 5, and an open position in which the mobile member 1 is physically separate from the stationary member 3, so that the electrical current between terminals 4, 5 is interrupted.
- the mobile member 1 carries an acceleration sensor 6.
- the acceleration sensor 6 is electrically isolated from contact pad 2.
- the mobile member 1 can e.g. be an elongate metallic body locally covered by an insulator layer to which the acceleration sensor 6 is affixed.
- the acceleration sensor 6 can comprise at least one micromechanical sensor, each e.g. etched from a silicon substrate, comprising an inertial body forming a first capacitor plate, elastically displaceable in the direction of displacement of the mobile member 1, e.g. by at least one resilient web connecting the inertial body to a frame, and a second capacitor plate spaced in the direction of displacement from the frame by an insulating layer and from the inertial body by a gap, so that the capacitance of a capacitor formed by said first and second plates varies depending on the distance between the capacitor plates, and acceleration of the mobile member 1 can be judged based on said capacitance, e.g. from the resonance frequency of a resonator circuit which includes the capacitor.
- micromechanical sensor each e.g. etched from a silicon substrate, comprising an inertial body forming a first capacitor plate, elastically displaceable in the direction of displacement of the mobile member 1, e.g. by at least one resilient web connecting the inertial body to a frame, and
- micromechanical sensors can be provided whose inertial body is displaceable in another direction, typically perpendicular to the displacement direction of the mobile member 1.
- the complete mobile member 1 from a semiconductor substrate, doped in a first region to form the contact pad 2 and doped and etched in a second region to form the sensor or sensors 6.
- Displacement of the mobile member 1 between open and closed positions is driven by a solenoid 8 interacting with a ferromagnetic body 9 attached to mobile member 1.
- magnetic attraction between the solenoid 8 and the ferromagnetic body 9 holds the mobile member 1 in the closed position.
- a spring may be provided for moving mobile member 1 into an open position, not shown, in which mobile member 1 is in contact with an abutment 10.
- the movement of mobile member 1 can be a translation. In the present embodiment, it is a rotation by an axis 7 perpendicular to the plane of Fig. 1 .
- the sensor 6 is located at a longer radius with respect to axis 7 than the contact pad 2, in order to be subject to a large and precisely detectable acceleration when moving between the open and closed positions.
- the radius of the sensor 6 with respect to axis 7 is also longer than that of abutment 10, and the sensor 6 is able to vibrate with respect to the mobile member 1, symbolized here by a sensor mount 12 connected to the mobile member 1 by a tapered portion 11.
- This flexibility enables the sensor 6 to overshoot when the movement of the mobile member 1 is stopped by the abutment 10, so that acceleration data obtained from the sensor 6 after the mobile member 1 making contact with the abutment 10 can be used for drawing conclusions on the state of the device.
- a resonance frequency of the mobile member 1 may be adapted to an expected duration of the movement of mobile member 1 between open and closed positions, so that as long as the movement does take the expected time, the overshoot is maximized, whereas when wear causes the movement to become slower or faster, this can be detected due to the reduction in overshoot.
- Acceleration data from sensor 6 are collected by a processing unit 13.
- the processing unit 13 can be a microcontroller or the like, accommodated in a same housing with the relay, or otherwise forming an assembly together with the relay.
- the processing unit 13 may come with a predefined set of data stored in it with which to compare data provided by the acceleration sensor 6 whenever the mobile member 1 is displaced between open and closed positions.
- a set of data is obtained from measurements carried out on the first displacements carried out by the mobile member 1 when the switching device is still new and can be assumed to be in good order.
- wear of the switching device can be detected, as will be explained in more detail later.
- the result of such a detection, output by processing unit 13, can be a binary judgment indicating that the relay is either in working order or is due for replacement. It can also be a quantitative score representative of the overall quality and/or expected remaining service life of the relay.
- the processing unit 13 includes a network interface 14 for communication with a remote unit 15 by a network 16 such as a LAN, a wireless network and/or the Internet.
- the remote unit 15 may collect information from a plurality of processing units 13. For instance, it can be run by an operator of an industrial plant to collect data from processing units of the entire plant or of subunits thereof, in order to keep maintenance staff informed of existing or imminent need to replace a relay or other device associated to one of these processing units.
- the network 16 is a WAN or the Internet
- the remote unit might also be run by a manufacturer of the relay, in order to be able to predict the when and where of future demand for replacement.
- Fig. 2 is a schematic diagram of an automatic fuse or a circuit breaker according to the present invention.
- the circuit breaker has many components in common with the relay of Fig. 1 ; these components are depicted identically in Figs. 1 and 2 and have identical reference numerals; their description will not be repeated.
- the main difference between the two devices is that while in the relay, the solenoid 8 must overcome the force of the spring acting on the mobile member 1 and is thus capable of controlling displacement from open to closed position and vice versa, the solenoid 8 of the circuit breaker is designed to withdraw a latch 17 which locks mobile member 1 in its closed position.
- a spring 18 urges mobile member 1 into the open position, i.e. the acceleration measured by sensor 6 is due to the force of the spring 18. In order to bring the mobile member 1 back into the closed position, manual intervention is necessary.
- Fig. 3 illustrates the movement of mobile member 1 when moving from closed to open position in the relay of Fig. 1 or the circuit breaker of Fig. 2 .
- a curve x representative of the position of the mobile member 1, starts from the closed position, the speed, represented by curve v, starts from zero.
- a curve a illustrates the acceleration; when the mobile member 1 is being displaced, acceleration sensor 6 provides samples of this curve a.
- a first phase (i) while the mobile member 1 moves towards the open position, the parabolic shape of curve x and the linear shape of curve v are representative of approximately constant negative acceleration a.
- the amount of this acceleration is governed by friction and by inertia of the mobile member and components coupled to it. When friction increases, the amount of acceleration decreases, so that a possible impending failure of the device may be predicted by processing unit 13 if this amount drops below a predetermined fraction of a normal acceleration measured for the same device when freshly installed. If, on the other hand, acceleration is higher than said normal acceleration, it must be expected that some mechanical connection within the device is broken, in which case the processing unit should output a signal calling for immediate replacement of the device.
- Duration of said first phase (i) should be inversely proportional to the amount of acceleration; therefore, the processing unit 13 can make use of the number of samples obtained in the first phase (i) to check plausibility of the detected acceleration amount. If the proportionality is violated, the path of the mobile member 1 may be obstructed, or the sensor 6 itself might be defective; in either case replacement of the device should be called for.
- acceleration switches to a high positive value.
- the amount of the positive acceleration and the duration of the (second) phase (ii) in which it persists depend on elasticity of abutment 10 and of the sensor mount, due e.g. to tapered portion 11. If there is no rebound, sums of accelerations measured in the first and second phases (i), (ii) should sum up to approximately zero. In case of rebound, the sum will be positive, and a third phase (iii) with negative acceleration will follow. If it doesn't, again there is reason to suspect some malfunction that might make replacement necessary.
- any increase or decrease of this duration will cause the vibration of the sensor mount to be excited less efficiently than normal, so that the number of subsequent phases (ii), (iii), ... showing accelerations in opposite directions strong enough to be detected will decrease.
- the number of direction changes of the acceleration detected after a displacement of the mobile member 1 may be taken as an indicator of the status of the device, a replacement of the device becoming the more urgent, the smaller the number of detected direction changes is.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Switches Operated By Changes In Physical Conditions (AREA)
Description
- The present invention relates to a device for switching electrical currents and/or voltages, typically for power switching, such as a relay or a circuit breaker.
- These devices typically comprise a stationary member, a mobile member that is displaceable between a closed position in which a contact pad of the mobile member is in electrically conductive contact with the stationary member, and an open position in which there is no electrically conductive contact, and an actuator for displacing the mobile member. When in such a device the mobile member is moved into or out of the closed position while a voltage is applied to the mobile and stationary members, an arc may form when the distance between the members is small enough but not zero, deteriorating the quality of the contacting surfaces of the mobile and stationary members. This may cause the surfaces to adhere to each other. Initially, weak adhesion may merely delay the switching operation, but if finally adhesion becomes too strong for the actuator to overcome, switching is prevented. Similarly, mechanical wear of the mobile member and its bearings may first merely delay the switching operation and finally prevent it altogether. Mechanical breakage might even cause the switching movement to become faster than normal, if the inertia of moving components is reduced.
-
EP 2 290 666 A1 -
WO 2018/108833 A1 discloses an electrical switching device in which life expectancy of a switching device is predicted based on its chattering behaviour, derived from current flowing through a Reed contact or through the solenoid driving the switching movement. This is a rather indirect way of judging life expectancy, since arc formation is not necessarily accompanied by chattering, but if arcs are formed, chattering will accelerate wear of contact surfaces. Therefore, if it is attempted to minimize downtime of a system by replacing switching devices thereof when these show suspicious chattering, there is a considerable probability that a switching device is replaced prematurely. Although such a replacement can be planned, and downtime for replacement can be kept short, it still causes an interruption of operation of the system in which the switching device is used, and potentially unnecessary cost. -
US 2019/0018065 A1 discloses a switching device in which an acceleration sensor is provided on a mobile member of the acceleration device for measuring acceleration thereof when the mobile member is being switched between closed and open positions, and wear of the switching device is detected based on output of the acceleration sensor. - The object of the present invention is to improve sensitivity of the acceleration sensor.
- The object is achieved by an electrical switching device as defined in
claim 1. The acceleration sensor is capable of detecting any irregularity of movement of the displaceable member, regardless of its cause. By making the distance between a first position of the sensor associated to the open position and a second position of the sensor associated to the closed position longer than the path of the contact pad between the open and close positions, the acceleration detected by the acceleration sensor is amplified. Specifically, the sensor and the contact pad can be rotatable by a same axis, the radius of the acceleration sensor being longer than that of the contact pad. - The actuator can be of any type, but typically comprises a solenoid adapted to interact magnetically with the mobile member. In an automatic fuse, most of the energy driving a displacement of the mobile member may be provided by a spring, the magnetic interaction of the solenoid merely serving to unlock the mobile member so as to enable its displacement by the spring.
- The acceleration sensor can be a micromechanical sensor. Such sensors are rugged and suitable for use in any orientation relative to the gravity vector. They are in widespread use e.g. for controlling airbags in motor vehicles and are therefore available at low cost.
- The acceleration sensor can be fixedly integrated into the mobile member, in order to follow its displacement as closely as possible.
- Alternatively, the acceleration sensor might be resiliently coupled to the mobile member. This can be useful in particular if the duration of the displacement of the displaceable member is known and constant; in that case the resonance period of the sensor mount can be tuned to the duration of the displacement so that any variation of that duration has a noticeable effect on the vibration of the sensor caused by the displacement.
- The bandwidth of the acceleration sensor should be high enough to obtain at least one acceleration measurement, i.e. higher than the inverse of the duration of a displacement of the mobile member between the open and closed positions. Preferably, it should be high enough to allow taking a plurality of acceleration measurements in the course of a displacement of the mobile member.
- The switching device may be associated to a processing unit which is adapted, e.g. programmed, to derive a judgment on the integrity of the switching device from current acceleration data obtained in relation to a current displacement of the mobile member between the first and second positions driven by the actuator.
- The switching device and the processing unit can be associated in the form of an assembly for joint installation.
- Alternatively, the processing unit can be remote from the switching device, communicating with the acceleration sensor via a digital network such as a LAN or the Internet.
- The processing unit can be adapted to derive the judgment on the integrity of the switching device from a comparison of said current acceleration data with standard acceleration data.
- Such standard acceleration data can be predetermined data, which may be provided by the manufacturer, for a specific type of switching device.
- Preferably, the processing unit is adapted to derive the standard acceleration data (or to update earlier standard data such as those provided by the manufacturer as mentioned above) based on acceleration data obtained in relation to earlier displacements of said mobile member. In that way, not only individual characteristics of the switching device that is being monitored can be taken into account, but also the influence of the orientation in which it is installed, in particular an influence of gravity on the displacement of the mobile member.
- The current acceleration data that are provided by the acceleration sensor in relation to a current switching movement should cover a time interval before and after an instant in which the mobile member reaches the second position. As is easily understood, data obtained before that instant are indicative of the condition of the mobile member in its first position, such as possible sticking, and of movement from the first position to the second, whereas data obtained after reaching the second position allow to draw conclusions on the condition of the mobile member in the second position.
- The switching device may comprise a network interface for outputting data of the acceleration sensor obtained in relation to a displacement of the mobile member, or data derived from these, e.g. by a local processing unit.
- Further features and advantages of the invention will become apparent from the subsequent description of embodiments thereof, referring to the appended drawings.
- Fig. 1
- is a schematic diagram of a relay according to the present invention;
- Fig. 2
- is a schematic diagram of a circuit breaker or an automatic fuse according to the present invention; and
- Fig. 3
- is an exemplary diagram of a switching movement.
-
Fig. 1 is a highly schematic representation of components of a relay. The relay has amobile member 1, which is displaceable between an closed position in which acontact pad 2 ofmobile member 1 is in electrically conductive contact with astationary member 3, allowing a current to flow betweenterminals mobile member 1 is physically separate from thestationary member 3, so that the electrical current betweenterminals - The
mobile member 1 carries anacceleration sensor 6. Theacceleration sensor 6 is electrically isolated fromcontact pad 2. Themobile member 1 can e.g. be an elongate metallic body locally covered by an insulator layer to which theacceleration sensor 6 is affixed. - The
acceleration sensor 6 can comprise at least one micromechanical sensor, each e.g. etched from a silicon substrate, comprising an inertial body forming a first capacitor plate, elastically displaceable in the direction of displacement of themobile member 1, e.g. by at least one resilient web connecting the inertial body to a frame, and a second capacitor plate spaced in the direction of displacement from the frame by an insulating layer and from the inertial body by a gap, so that the capacitance of a capacitor formed by said first and second plates varies depending on the distance between the capacitor plates, and acceleration of themobile member 1 can be judged based on said capacitance, e.g. from the resonance frequency of a resonator circuit which includes the capacitor. - If desired, further micromechanical sensors can be provided whose inertial body is displaceable in another direction, typically perpendicular to the displacement direction of the
mobile member 1. - In a miniaturized embodiment, it would be conceivable to form the complete
mobile member 1 from a semiconductor substrate, doped in a first region to form thecontact pad 2 and doped and etched in a second region to form the sensor orsensors 6. - Displacement of the
mobile member 1 between open and closed positions is driven by asolenoid 8 interacting with aferromagnetic body 9 attached tomobile member 1. In the embodiment shown, magnetic attraction between thesolenoid 8 and theferromagnetic body 9 holds themobile member 1 in the closed position. A spring, not shown, may be provided for movingmobile member 1 into an open position, not shown, in whichmobile member 1 is in contact with anabutment 10. - The movement of
mobile member 1 can be a translation. In the present embodiment, it is a rotation by anaxis 7 perpendicular to the plane ofFig. 1 . Thesensor 6 is located at a longer radius with respect toaxis 7 than thecontact pad 2, in order to be subject to a large and precisely detectable acceleration when moving between the open and closed positions. - In this embodiment, the radius of the
sensor 6 with respect toaxis 7 is also longer than that ofabutment 10, and thesensor 6 is able to vibrate with respect to themobile member 1, symbolized here by asensor mount 12 connected to themobile member 1 by atapered portion 11. This flexibility enables thesensor 6 to overshoot when the movement of themobile member 1 is stopped by theabutment 10, so that acceleration data obtained from thesensor 6 after themobile member 1 making contact with theabutment 10 can be used for drawing conclusions on the state of the device. For example, a resonance frequency of themobile member 1 may be adapted to an expected duration of the movement ofmobile member 1 between open and closed positions, so that as long as the movement does take the expected time, the overshoot is maximized, whereas when wear causes the movement to become slower or faster, this can be detected due to the reduction in overshoot. - Acceleration data from
sensor 6 are collected by aprocessing unit 13. Theprocessing unit 13 can be a microcontroller or the like, accommodated in a same housing with the relay, or otherwise forming an assembly together with the relay. - The
processing unit 13 may come with a predefined set of data stored in it with which to compare data provided by theacceleration sensor 6 whenever themobile member 1 is displaced between open and closed positions. Preferably, such a set of data is obtained from measurements carried out on the first displacements carried out by themobile member 1 when the switching device is still new and can be assumed to be in good order. By comparing data obtained in later displacements with these, wear of the switching device can be detected, as will be explained in more detail later. The result of such a detection, output by processingunit 13, can be a binary judgment indicating that the relay is either in working order or is due for replacement. It can also be a quantitative score representative of the overall quality and/or expected remaining service life of the relay. - The
processing unit 13 includes anetwork interface 14 for communication with aremote unit 15 by anetwork 16 such as a LAN, a wireless network and/or the Internet. Theremote unit 15 may collect information from a plurality ofprocessing units 13. For instance, it can be run by an operator of an industrial plant to collect data from processing units of the entire plant or of subunits thereof, in order to keep maintenance staff informed of existing or imminent need to replace a relay or other device associated to one of these processing units. In particular if thenetwork 16 is a WAN or the Internet, the remote unit might also be run by a manufacturer of the relay, in order to be able to predict the when and where of future demand for replacement. -
Fig. 2 is a schematic diagram of an automatic fuse or a circuit breaker according to the present invention. The circuit breaker has many components in common with the relay ofFig. 1 ; these components are depicted identically inFigs. 1 and 2 and have identical reference numerals; their description will not be repeated. The main difference between the two devices is that while in the relay, thesolenoid 8 must overcome the force of the spring acting on themobile member 1 and is thus capable of controlling displacement from open to closed position and vice versa, thesolenoid 8 of the circuit breaker is designed to withdraw alatch 17 which locksmobile member 1 in its closed position. When that happens, a spring 18 urgesmobile member 1 into the open position, i.e. the acceleration measured bysensor 6 is due to the force of the spring 18. In order to bring themobile member 1 back into the closed position, manual intervention is necessary. -
Fig. 3 illustrates the movement ofmobile member 1 when moving from closed to open position in the relay ofFig. 1 or the circuit breaker ofFig. 2 . A curve x, representative of the position of themobile member 1, starts from the closed position, the speed, represented by curve v, starts from zero. A curve a illustrates the acceleration; when themobile member 1 is being displaced,acceleration sensor 6 provides samples of this curve a. - In a first phase (i), while the
mobile member 1 moves towards the open position, the parabolic shape of curve x and the linear shape of curve v are representative of approximately constant negative acceleration a. The amount of this acceleration is governed by friction and by inertia of the mobile member and components coupled to it. When friction increases, the amount of acceleration decreases, so that a possible impending failure of the device may be predicted by processingunit 13 if this amount drops below a predetermined fraction of a normal acceleration measured for the same device when freshly installed. If, on the other hand, acceleration is higher than said normal acceleration, it must be expected that some mechanical connection within the device is broken, in which case the processing unit should output a signal calling for immediate replacement of the device. - Duration of said first phase (i) should be inversely proportional to the amount of acceleration; therefore, the
processing unit 13 can make use of the number of samples obtained in the first phase (i) to check plausibility of the detected acceleration amount. If the proportionality is violated, the path of themobile member 1 may be obstructed, or thesensor 6 itself might be defective; in either case replacement of the device should be called for. - When the mobile member reaches
abutment 10, acceleration switches to a high positive value. The amount of the positive acceleration and the duration of the (second) phase (ii) in which it persists depend on elasticity ofabutment 10 and of the sensor mount, due e.g. to taperedportion 11. If there is no rebound, sums of accelerations measured in the first and second phases (i), (ii) should sum up to approximately zero. In case of rebound, the sum will be positive, and a third phase (iii) with negative acceleration will follow. If it doesn't, again there is reason to suspect some malfunction that might make replacement necessary. - In a simple embodiment, requiring only a low temporal resolution of the
acceleration sensor 6, it may be sufficient simply to monitor the duration of alternating phases of positive and negative acceleration after a displacement of themobile member 1. When the normal duration of the displacement (i.e. phase (i)) is tuned to the resonance period of the sensor mount, any increase or decrease of this duration will cause the vibration of the sensor mount to be excited less efficiently than normal, so that the number of subsequent phases (ii), (iii), ... showing accelerations in opposite directions strong enough to be detected will decrease. Here, simply the number of direction changes of the acceleration detected after a displacement of themobile member 1 may be taken as an indicator of the status of the device, a replacement of the device becoming the more urgent, the smaller the number of detected direction changes is. -
- 1
- mobile member
- 2
- contact pad
- 3
- stationary member
- 4
- terminal
- 5
- terminal
- 6
- acceleration sensor
- 7
- axis
- 8
- solenoid
- 9
- ferromagnetic body
- 10
- abutment
- 11
- tapered portion
- 12
- sensor mount
- 13
- processing unit
- 14
- network interface
- 15
- remote unit
- 16
- network
- 17
- latch
- 18
- spring
Claims (12)
- Electrical switching device comprising a stationary member (3), a mobile member (1) which is displaceable between a closed position in which a contact pad (2) of the mobile member (1) is in electrically conductive contact with the stationary member (3), and an open position in which the electrically conductive contact does not exist, an actuator (8, 18) for displacing the mobile member (1) from at least a first one of the closed and open positions to the second one, and an acceleration sensor (6) which is coupled to the mobile member (1) so as to sense an acceleration caused by the actuator (8, 18) displacing the mobile member (1), characterized in that the acceleration sensor (6) is coupled to the mobile member (1) so that the distance between a first position of the sensor (6) associated to the open position and a second position of the sensor (6) associated to the closed position is longer than the path of the contact pad (2) between the open and close positions.
- The electrical switching device of claim 1, wherein the actuator (8, 18) comprises a solenoid (8) adapted to interact magnetically with the mobile member (1).
- The electrical switching device of claim 1 or 2, wherein the acceleration sensor (6) is a micromechanical sensor.
- The electrical switching device of any of claims 1 to 3, wherein the acceleration sensor (6) is fixedly integrated into the mobile member (1).
- The electrical switching device of any of claims 1 to 3, wherein the acceleration sensor (6) is resiliently coupled to the mobile member (1).
- The electrical switching device of any of the preceding claims, wherein the bandwidth of the acceleration sensor (6) is higher than the inverse of the duration of a displacement of the mobile member between the open and closed positions driven by the actuator, so that the bandwidth is high enough to obtain at least one acceleration measurement in the course of a displacement of the mobile member.
- The electrical switching device of any of the preceding claims, characterized in that it is a relay, a circuit breaker or an automatic fuse.
- An assembly comprising the electrical switching device of any of the preceding claims and a processing unit (13) for deriving a judgment on the integrity of the switching device from current acceleration data (a) obtained in relation to a current displacement of the mobile member (1) between the first and second positions driven by the actuator (8, 18).
- The assembly of claim 8, wherein the processing unit (13) is adapted to derive the judgment from a comparison of said current acceleration data (a) with standard acceleration data.
- The assembly of claim 9, wherein the processing unit (13) is adapted to derive the standard acceleration data from acceleration data obtained in relation to earlier displacements of said mobile member (1).
- The assembly of claim 8, 9, or 10, wherein the current acceleration data (a) cover a time interval (i, ii, iii, ...) before and after an instant in which the mobile member (1) reaches the second position.
- The assembly of any of the preceding claims, further comprising a network interface (14) for outputting data of the acceleration sensor (6) obtained in relation to a displacement of the mobile member, or a judgment derived from these.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP20165095.9A EP3886128B1 (en) | 2020-03-24 | 2020-03-24 | Electrical switching device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP20165095.9A EP3886128B1 (en) | 2020-03-24 | 2020-03-24 | Electrical switching device |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3886128A1 EP3886128A1 (en) | 2021-09-29 |
EP3886128B1 true EP3886128B1 (en) | 2024-01-24 |
Family
ID=69960328
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20165095.9A Active EP3886128B1 (en) | 2020-03-24 | 2020-03-24 | Electrical switching device |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP3886128B1 (en) |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ATE533063T1 (en) * | 2009-04-22 | 2011-11-15 | Omicron Electronics Gmbh | DEVICE AND METHOD FOR CHECKING A SWITCHING PROCESS OF AN ELECTRICAL SWITCH |
EP2290666B1 (en) | 2009-08-27 | 2015-08-12 | Siemens Aktiengesellschaft | Auxiliary module with lifespan monitoring for electromagnetic switching devices and accompanying method |
DE102010026528A1 (en) * | 2010-07-08 | 2012-01-12 | Areva Energietechnik Gmbh | Electric circuit breaker and method for operating an electrical circuit breaker |
LU93350B1 (en) | 2016-12-12 | 2018-07-03 | Phoenix Contact Gmbh & Co Kg Intellectual Property Licenses & Standards | Method for monitoring an electromechanical component of an automation system |
DE102017102637A1 (en) * | 2017-02-10 | 2018-08-16 | Pilz Gmbh & Co. Kg | Circuit arrangement for operating at least one relay |
WO2018224155A1 (en) * | 2017-06-08 | 2018-12-13 | Abb Schweiz Ag | Monitoring device for switching systems |
FR3069064B1 (en) * | 2017-07-13 | 2022-02-11 | Schneider Electric Ind Sas | ELECTRICAL SWITCHING DEVICE AND ASSOCIATED WEAR DETECTION METHOD |
-
2020
- 2020-03-24 EP EP20165095.9A patent/EP3886128B1/en active Active
Also Published As
Publication number | Publication date |
---|---|
EP3886128A1 (en) | 2021-09-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN111801758B (en) | Contactor with contact carrier position sensing | |
US8688391B2 (en) | Method for determining contact erosion of an electromagnetic switching device, and electromagnetic switching device comprising a mechanism operating according to said method | |
US9287064B2 (en) | Switching device and method for detecting malfunctioning of such a switching device | |
CN110709953B (en) | Monitoring device for a switching system | |
WO2012128075A1 (en) | Electromagnetic opening/closing device | |
US8264232B2 (en) | Evaluation of the integrity of depressed contacts by variation of the rotation of the pole-shaft | |
US4488078A (en) | Brush wear detector | |
JP2012199115A (en) | Electromagnetic switch | |
EP3370244B1 (en) | Electromagnetic operation device and electromagnetic operation-type switching apparatus | |
JP7452980B2 (en) | sensor | |
JP2023130497A (en) | sensor | |
EP3886128B1 (en) | Electrical switching device | |
EP3428936A1 (en) | Electromagnetically moving device | |
KR101560210B1 (en) | Attachment module with life monitoring for an electromagnetic switching device, and associated method | |
US10479646B2 (en) | Solution for compensating an effect of temperature change in a proximity sensor in a machinery brake of an elevator | |
KR20220116126A (en) | Vacuum circuit breaker equipped with a function of realtime monitoring and the monitoring method | |
US10340640B2 (en) | System and method for determining the current condition of power contacts | |
US20230268723A1 (en) | Method for Determining the State of an Electrical Switchgear Assembly, Monitoring Unit for an Electrical Switchgear Assembly, And Electrical Switchgear Assembly | |
JP6766019B2 (en) | Vacuum switchgear and its abnormality monitoring method | |
JP7006548B2 (en) | Switch | |
JP2009212024A (en) | Switching device | |
CN221425628U (en) | GIS isolator overrun distance detection device | |
KR20190020128A (en) | Actuator for medium voltage circuit breaker | |
JP7382916B2 (en) | vacuum circuit breaker | |
WO2024086327A1 (en) | Economizing electromechanical contactors |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20220401 |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: GRANT OF PATENT IS INTENDED |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: H01H 71/04 20060101ALN20230818BHEP Ipc: H01H 11/00 20060101ALI20230818BHEP Ipc: H01H 1/00 20060101AFI20230818BHEP |
|
INTG | Intention to grant announced |
Effective date: 20230912 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE PATENT HAS BEEN GRANTED |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 602020024685 Country of ref document: DE |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20240320 Year of fee payment: 5 |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG9D |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MP Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240524 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240425 |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 1652848 Country of ref document: AT Kind code of ref document: T Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 Ref country code: RS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240424 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20240124 |