EP2509092A1 - Electric switching device - Google Patents
Electric switching device Download PDFInfo
- Publication number
- EP2509092A1 EP2509092A1 EP12162452A EP12162452A EP2509092A1 EP 2509092 A1 EP2509092 A1 EP 2509092A1 EP 12162452 A EP12162452 A EP 12162452A EP 12162452 A EP12162452 A EP 12162452A EP 2509092 A1 EP2509092 A1 EP 2509092A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- switching device
- pole
- output
- overcurrent
- poles
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims abstract description 38
- 238000000926 separation method Methods 0.000 claims description 13
- 238000012360 testing method Methods 0.000 claims description 7
- 230000007423 decrease Effects 0.000 claims description 5
- 238000004804 winding Methods 0.000 description 15
- 230000007246 mechanism Effects 0.000 description 8
- 238000009825 accumulation Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
- H01H83/20—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition
- H01H83/22—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages
- H01H83/226—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages with differential transformer
-
- 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
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/123—Automatic release mechanisms with or without manual release using a solid-state trip unit
- H01H71/125—Automatic release mechanisms with or without manual release using a solid-state trip unit characterised by sensing elements, e.g. current transformers
Definitions
- the present invention relates to an electric switching device for a low voltage circuit having improved characteristics of overcurrent protection.
- switching devices used in low voltage electric circuits (that is for applications with nominal voltages up to 1000V AC / 1500V DC), for example circuit breakers, disconnectors, and contactors designated as “switching devices", are all devices designed to ensure the protection of electric circuits and the safety of the users of the electric circuits themselves, by intervening upon the detection of a failure condition.
- Circuit breakers comprise one or more electric poles having at least a moving contact adapted to assume a first position in which it is coupled to a corresponding stationary contact (closed switching device), and a second position, in which it is decoupled from the corresponding stationary contact (open switching device).
- the switching devices are generally provided with means adapted to protect against the occurrence of critical differential currents between the poles of the switching devices themselves, caused by an earth leakage current (also known as residual current or imbalance current).
- an earth leakage current also known as residual current or imbalance current
- the switching devices are provided with means adapted to protect against the occurrence of electrical currents having a critical value higher than the nominal operating current; such overcurrents can be non instantaneous (when caused for example by an overload condition), or instantaneous (when caused for example by a short-circuit).
- switching devices of the modular type are known that implement, together with the protection against differential currents, the protection from overcurrents by means of magneto-thermal means, and for this reason are known as "residual current circuit breakers with overcurrent protection” (RCBO).
- the protection from non-instantaneous overcurrents is carried out by a bimetallic element operatively connected to one or more poles, or phases, that are to be protected from overcurrents.
- the bimetallic element is inserted along the path of the current flowing in a phase of the switching device.
- the bimetallic element flexes and operatively interacts with the moving contacts of the switching device, so as to cause the separation of the moving contacts themselves from the corresponding stationary contacts.
- the predetermined threshold for the current flowing through the bimetallic element is equal to the value of the nominal current plus about 45% of the value itself; further, the flowing of the current must be guaranteed with a tolerance on the nominal operating value equal to about 15%.
- the intervention time necessary to the bimetallic element to open the switching device decreases as the overcurrent passing through it increases, according to a relationship described by a characteristic curve known as "inverse time characteristic curve".
- the bimetallic element Even though the bimetallic element fully achieves its intended function and is a particularly economic solution, it implies a number of disadvantages and challenges.
- the bimetallic element must be accurately calibrated in order to operate properly according to the current flowing through it.
- certain applications do not allow overcurrents that are 20% higher than the nominal operating current, even requiring a tolerance on the nominal operating value equal to about 15%.
- the calibration of the bimetallic element in a very narrow range is critical, and results in substantial discards in the production of the switching devices.
- the bimetallic element is a particularly temperature-sensitive device, and therefore requires a compensation of the variations of the room temperature, which may be substantial when the switching device is installed in critical environments.
- the objective of the present invention is to provide a switching device having overcurrent protection means that allow to overcome the disadvantages highlighted in the prior art, while adopting a particularly simple and economical solution.
- an electric switching device for a low voltage electric circuit comprising:
- the switching device comprises second detection means which are adapted to detect an overcurrent flowing in at least one of said first and second poles, and which comprise at least a current transformer operatively connected to said at least one of the first and second poles.
- the switching device according to the present invention will be described hereinafter by making reference to one of its embodiments as a miniature differential circuit breaker (of the modular type) provided with protection against overcurrent.
- the principles and technical solutions described in the course of the following description are to be understood in any event to be also valid for different types of switching device, such as for example molded case circuit breakers (MCCB).
- Figure 1 schematically illustrates a circuit breaker 1 for a low voltage circuit, in particular a miniature circuit breaker 1, comprising a first pole 2 and a second pole 3.
- the first pole 2 comprises a first moving contact 4 which can be coupled to/decoupled from a corresponding first stationary contact 5; in turn, the second pole 3 comprises a second moving contact 6 which can be coupled to/decoupled from a corresponding second stationary contact 7.
- the first pole 2 comprises a first electrical terminal 8 and a second electrical terminal 9, and the second pole 3 comprises a third electrical terminal 10 and a fourth electrical terminal 11.
- Such electrical terminals 8, 9, 10, 11 are adapted to electrically connect the first pole 2 and the second pole 3 to the electric circuit where circuit breaker 1 is installed; in particular, they are adapted to operatively connect a power supply source (LINE) to an electric load (LOAD) of the associated electric circuit, by means of the first pole 2 and the second pole 3.
- circuit breaker 1 may have a number of poles different than that illustrated in the example in figure 1 .
- the first moving contact 4 and the second moving contact 6 are operatively connected to an operating mechanism 12 adapted to cause the separation of the first and second moving contacts 4, 6 from the corresponding stationary contacts 5, 7 as a result of its actuation;
- the operating mechanism 12 is of the type known in the art, and will therefore not be described in detail.
- the circuit breaker 1 comprises first detection means adapted to detect a differential current between the first pole 2 and the second pole 3.
- the first detection means are operatively connected to the first moving contact 4 and the second moving contact 6 so as to cause the separation of the first and second moving contacts 4, 6 from the corresponding first and second stationary contacts 5, 7 upon the detection of a differential current between the first pole 2 and the second pole 3 greater than a predetermined intervention threshold, for example 0.03 A.
- the first detection means are configured so as to cause the intervention of the actuating means 30 of circuit breaker 1.
- Such actuating means 30, of the type known in the state of the art are adapted to operatively interact with the first moving contact 4 and the second moving contact 6 so as to cause the separation of the first and second moving contacts 4, 6 from the corresponding first and second stationary contacts 5, 7.
- the actuating means 30 are operatively connected to the operating mechanism 12, so as to cause the operation of the operating mechanism 12 itself, by means of its intervention.
- the first detection means comprise a differential current transformer 20 (or current summing transformer 20), operatively connected to the first pole 2 and the second pole 3, so as to generate an electric output signal S 1 that depends on the differential current between the first pole 2 and the second pole 3.
- a differential current transformer 20 or current summing transformer 20
- the differential current transformer 20 comprises a magnetic core 21 crossed by a part of the first pole 2 and a part of the second pole 3, which constitute the primary winding of the differential current transformer 20.
- a secondary winding 22 is wound around the magnetic core 21.
- the current flowing through the first pole 2 and the corresponding current flowing through the second pole 3 are equal in value; the magnetic fields generated by the two currents cancel each other and no electric signal is generated in the secondary winding 22.
- the unbalance between the current flowing through the first pole 2 and the current flowing through the second pole 3 generates a magnetic field that induces the electric signal S 1 in the secondary winding 22.
- the value of the electric signal S 1 is indicative of the value of the differential current between the first pole 2 and the second pole 3.
- the first detection means comprise electronic means 23 which are adapted to receive in input the electric signal S 1 , and which are configured so as to detect a differential current between the first pole 2 and the second pole 3 through the electric signal S 1 .
- the electronic means 23 are configured to compare the electric signal S 1 received in input with a predetermined threshold value, so as to detect the presence of a differential current between the first pole 2 and the second pole 3 that is greater than the predetermined intervention threshold. When such predetermined threshold value is exceeded, the electronic means 23 are configured so as to output a control signal S 2 .
- Control signal S 2 is suitable for causing the intervention of the actuating means 30 on the operating mechanism 12, providing the actuating means 30 themselves with the energy necessary for their intervention.
- the first detection means (and the corresponding actuating means 30) are configured in order to operate independently from the voltage of the electric circuit where circuit breaker 1 itself is installed; that is to say, to operate independently from the voltage applied to the first and third electric terminals 8, 10 or to the second and fourth electric terminals 9, 11, under operating conditions of circuit breaker 1.
- the electronic means 23 are configured to operate using only the energy associated to the electric signal S 1 received in input.
- the electronic means 23 remain inactive, or quiescent, until the electric signal S 1 is sent to their input.
- the electronic means 23 are realized by one or more electronic analog blocks.
- the circuit breaker 1 comprises test means 24 operatively connected to the first detection means so as to simulate the generation of a differential current between the first pole 2 and the second pole 3 that is greater than the predetermined intervention threshold.
- test means 24 comprise a test button which realizes, when pressed, an electric circuit inside the circuit breaker 1 which is adapted to supply a voltage to a second primary winding 25 wound around magnetic core 21. The current that begins to flow in the second primary winding 25 as a result of the application of the voltage, induces a magnetic field suitable for generating the electric signal S 1 in the secondary winding 22.
- the circuit breaker 1 further comprises second detection means adapted to detect an overcurrent flowing in at least one of the first pole 2 and second pole 3.
- Overcurrent must be understood as a current with value exceeding the value of the nominal operating current.
- Overcurrents can be non-instantaneous (typically with a duration in time in the order of minutes), mainly caused by an overload condition; or can be instantaneous currents, caused for example by a short-circuit failure.
- Second detection means are operatively connected to the first moving contact 4 and the second moving contact 6, so as to cause the separation of the first and second moving contacts 4, 6 themselves from the corresponding first and second stationary contacts 5, 7 as a result of the detection of an overcurrent greater than a predetermined intervention threshold.
- the second detection means are configured to cause the intervention of the actuating means 30 of the circuit breaker 1, the same actuating means 30 driven by the first detection means as previously described.
- the same actuating means 30 are advantageously used to actuate both the protection against differential currents and overcurrents; alternatively, the second detection means can drive actuating means dedicated only to the protection against overcurrent, separated from the actuating means 30 dedicated only to the protection against differential currents.
- the second detection means comprise at least a current transformer 50 operatively connected to the first pole 2 and/or the second pole 3 so as to output an electric signal S 3 depending on the current flowing in the first pole 2 or in the second pole 3.
- the first pole 2, or phase 2 of the circuit breaker 1 is protected against overcurrent by means of the current transformer 50.
- the second pole 3, or neutral 3 is without a current transformer 50; protection against overcurrent for the second pole 3 is in fact implemented indirectly by means of the current transformer 50 of the first pole 2, since that the first detection means guarantee equality between the current flowing through the first pole 2 and the second pole 3, with the exception of a differential current smaller than the predetermined intervention threshold.
- both the first pole and second poles 2, 3 may be phases 2, 3 of the circuit breaker 1 protected against overcurrents by means of a first current transformer 50 and a second current transformer 50, respectively.
- some or all the poles of a circuit breaker 1 with more than two poles may be provided with protection against overcurrent (implemented by means of a respective current transformer 50).
- a tripolar circuit breaker 1 may be configured with three phases, or a quadrupole circuit breaker 1 may be configured with three phases and neutral, or with four phases.
- the current transformer 50 comprises a magnetic core 51 crossed by a part of the first pole 2, which constitutes the primary winding of the current transformer 50 itself.
- a secondary winding 52 is wound around the magnetic core 51; a magnetic field is generated by a current flowing through the first pole 2 so as to induce the electric signal S 3 in the secondary winding 52 with a value indicative of the value of the current flowing through the first pole 2.
- the current transformer 50 is configured so that the electric signal S 3 output by means of the secondary winding 52 is in the same order of magnitude as the electric signal S 1 output by the differential current transformer 20, even though the value of the overcurrent flowing through the first pole 2 is much greater (many orders of magnitude) than the value of the differential current that may occur between the first pole and second poles 2, 3.
- such aim is achieved by using a magnetic core 51 with magnetic permeability sufficiently low to generate the output signal S 3 with the same order of magnitude as the output signal S 1 .
- the current transformer 50 comprises a magnetic core 510 having an air gap 511 dimensioned so that the electric signal S 3 output by means of the secondary winding 52 is in the same order of magnitude as the output signal S 1 .
- the use of the magnetic core 510 further simplifies the manufacturing process of the circuit breaker 1, since the electric conductors that realize a portion of the conduction path of the first pole 2 may be first inserted into the circuit breaker 1 and soldered to the respective electric terminals 8, 9 of the first pole 2. Thereafter, the magnetic core 510 is placed around a corresponding part of an electric conductor of the first pole 2 by inserting such part into the magnetic core 510 through the air gap 511.
- the second detection means comprise electronic means 53 adapted to receive in input the electric signal S 3 output by the current transformer 50 and which are configured to detect an overcurrent flowing through the first pole 2, using the electric signal S 3 .
- the electronic means 53 are configured to compare the electric signal S 3 received in input, preferably adjusted by means of an input block, with a predetermined threshold value, so as to detect the presence of an overcurrent greater than the predetermined intervention threshold.
- the electronic means 53 are configured to output a control signal S 4 .
- Control signal S 4 is suitable for causing the intervention of the actuating means 30, which actuate the operating mechanism 12, supplying to the actuating means 30 themselves the energy necessary for intervening.
- the signal S 4 may be sent to other actuating means, dedicated only to protecting against overcurrent.
- the second detection means are preferably also configured to operate independently from the voltage of the electric circuit where the circuit breaker 1 is installed.
- the electronic means 53 are configured to operate using only the energy of the electric signal S 3 receive in input. In practice, the electronic means 53 remain inactive or quiescent until the electric signal S 3 is sent to their input.
- the electronic means 53 may be implemented in a simple manner, without the provision for the circuit breaker 1 to have means suitable for drawing the voltage between the first pole and second pole 2, 3, and for adjusting such voltage in order to be applied to the electronic means 53.
- the electronic means 53 comprise a chain of electronic analog blocks.
- the functionalities of the electronic analog blocks may be implemented with a digital electronic unit, such as an electronic processing unit, for example a micro-controller.
- the current transformer 50 is configured to output the electric signal S 3 with sufficient energy to supply the digital electronic unit; an overcurrent flowing in the first pole 2 has a high value and therefore owns the necessary energy to generate an electric signal S 3 at the output of transformer 50 suitable for supplying the digital electronic unit.
- the electronic means 53 are configured so that the delay time between the receiving in input of the electric signal S 2 and the outputting of the control signal S 4 decreases as the value of the detected overcurrent increases.
- the dependence of the delay time on the value of the detected overcurrent is described by a characteristic curve with a decreasing trend (inverse time characteristic curve).
- the delay in the generation of the control signal S 4 produces a delay in the intervention of the actuating means 30 on the operating mechanism 12 for causing the separation of the first and second moving contacts 4, 6 from the respective first and second stationary contacts 5, 7.
- the overcurrents flowing through the first pole 2 that are only slightly higher than the predetermined intervention threshold are therefore allowed also for long times, while overcurrents with increasing values are allowed for shorter times.
- the electronic means 53 are configured to implement only the protection from non-instantaneous overcurrents, which are mainly caused by overload conditions.
- the electronic means 53 can be implemented according to simple design specifications.
- Figure 4 shows, for an exemplary but not limiting purpose, an inverse time characteristic curve 500 which describes the trend of the intervention time associated to the electronic means 53 configured to implement the protection from non instantaneous overcurrent; such inverse time characteristic curve 500 describes the intervention time of a bimetallic element, used in the prior art for the protection against non instantaneous overcurrent.
- the electronic means 53 are configured to simulate the intervention of the bimetallic element against currents caused by overload conditions.
- the circuit breaker 1 comprises, in addition to the actuating means 30, at least a release actuator 32 (of the type known in the prior art) connected to one or more poles of the circuit breaker itself, in such a way that the current that flows through the poles themselves (or a portion of said current) also flows through it.
- the release actuator 32 is inserted along the path of the respective phase 2 of the circuit breaker 1 and is configured to act on the operating mechanism 12 upon the occurrence of an instantaneous overcurrent, so as to cause the separation of the first and second moving contacts 4, 6 from the respective first and second stationary contacts 5, 7.
- circuit breaker 1 illustrated in figure 1 is schematically depicted an electromagnetic release actuator 32 inserted along the conduction path of the first pole 2 of the circuit breaker 1.
- the electronic means 53 are configured to implement, in addition to the protection against non-instantaneous overcurrent, also the protection against instantaneous overcurrent, which are mainly due to short-circuit faults.
- the electronic means 53 must be configured so that the time delay between the detection of the instantaneous overcurrent and the generation in output of the control signal S 4 is sufficiently short to guarantee an effective intervention against an instantaneous type event.
- the electronic means 53 have the advantage of being configured to also simulate the intervention of the electromagnetic actuator 32 against an instantaneous overcurrent, and therefore the presence of the electromagnetic actuator 32 in circuit breaker 1 is not necessary.
- the described solution is particularly advantageous for applications where the predetermined intervention threshold against an instantaneous overcurrent is not much greater than the predetermined intervention threshold for non-instantaneous overcurrent; for example, reference can be made to an application where the intervention threshold against an instantaneous overcurrent is equal to twice the value of the nominal operating current.
- the electronic means 53 which can be used in the circuit breaker 1 according to the present invention, is described in detail by making reference to the block diagram illustrated in figure 2 .
- the electronic means 53 in figure 2 comprise a chain of three circuit blocks 54, 55, 56 operatively connected to each other.
- the first block 54, or input block 54 receives in input the electric signal S 3 output by the current transformer 50, and comprises an adjustment circuit having preferably simple electronic elements such as diodes, resistors, and capacitors; the adjustment circuit is configured to conveniently adjust the electric signal S 3 .
- the adjusted electric signal S 3 is sent from the input block 54 to the second circuit block 55, or energy accumulation block 55, which comprises electronic means to accumulate the energy associated to the adjusted electric signal S 3 .
- the third circuit block 56, or output block 56 is connected to the energy accumulation block 55 and comprises a comparison device, preferably a voltage detector, which receives in input the energy accumulated in the energy accumulation block 55 in order to compare the value of the adjusted electric signal S 3 to a predetermined threshold value.
- the output block 56 is configured to output the energy received from the energy accumulation block 55 (thus outputting the control signal S 4 for the actuating means 30), when the energy received in input corresponds to a value of the adjusted electric signal S 3 greater than the predetermined threshold of the comparator device.
- the input block 54 is designed so that the adjusted electric signal S 3 is greater than the threshold of the comparator device of the output block 56 when an overcurrent flowing through the first pole 2 of the circuit breaker 1 is greater than the predetermined intervention threshold.
- the energy output by the energy accumulation block 55 reaches the predetermined threshold for generating control signal S 4 faster for larger values of the adjusted electric signal S 3 .
- the time delay between the application of electric signal S 3 at the input block 54 and the generation of the control signal S 4 at output block 56 decreases as the value of the electric signal S 3 increases, and thus such time delay decreases as the value of the detected overcurrent increases.
- the electronic means 23 of the first detection means and the electronic means 53 of the second detection means operate in parallel in the same circuit block 100 (depicted schematically in figure 1 ), sharing at least an output block of the circuit block 100 itself.
- Figure 3 illustrates a non-limiting example of the circuit block 100, wherein the electronic means 23 for the protection against differential current and the electronic means 53 shown in figure 2 are present; such electronic means 23 and 53 operate in parallel sharing the output block 56.
- the electronic means 23 realize a first processing branch for the electric signal S 1 received in input, while the second electronic means 53 realize a second processing branch for the electric signal S 3 received in input.
- the first and second processing branches operate in parallel independently to generate the control signal S 2 and the control signal S 4 by means of the same output block 56 of the circuit block.
- the electronic means 23 comprise at least a circuit block for adjusting the electric signal S 1 ; said adjustment block is designed so that the adjusted signal S 1 exceeds the threshold of the comparator device of output block 56 when the differential current present between the first pole and second poles 2, 3 is greater than the predetermined intervention threshold.
- the circuit breaker 1 comprises test means 57 operatively connected to the second detection means in order to simulate the occurrence of an overcurrent greater than the predetermined intervention threshold.
- the test means 57 comprise a test button which, as a result of being activated, realizes an electric circuit inside the circuit breaker 1 adapted to apply a voltage to a second primary winding 58 wound around the magnetic core 51.
- the current that begins to flow in the second primary winding 58 as a result of the application of the voltage induces a magnetic field suitable for generating the electric signal S 3 in the first secondary winding 52.
- circuit breaker 1 In practice it has been observed that the circuit breaker 1 according to the present invention fully achieves the pre-established objectives.
- the protection from overcurrent, and in particular from non-instantaneous overcurrent caused by an overload, is carried out by using the current transformer 50 which, unlike a bimetallic element, does not need to be calibrated and functions substantially independently of environmental temperature.
- the current transformer 50 is also used to protect against instantaneous overcurrent caused by short-circuit faults, avoiding the use of electromagnetic actuators dedicated to protecting against short-circuit current.
- the solution described is particularly simple and economical to implement.
- the use of the same actuating means 30 to implement the protection against differential current and overcurrent, as well as the fact of implementing the electronic means 23 and the electronic means 53 in the same circuit block 100, as the branches that operate in parallel sharing at least the output block of circuit block 100 itself, allow to optimize the available resources in order to obtain a particularly simple and economical solution.
- the electronic means 23 and the electronic means 53 may belong to two completely separate circuit blocks; and/or the actuating means controlled by the electronic means 23 and the electronic means 53 may be different.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
- Relay Circuits (AREA)
- Electronic Switches (AREA)
Abstract
- at least a first pole (2) having a first moving contact (4) which can be coupled to/decoupled from a corresponding first stationary contact (5), and a second pole (3) having a second moving contact (6), which can be coupled to/decoupled from a corresponding second stationary contact (7);
- first detection means adapted to detect a differential current between said first and second poles (2, 3), said first detection means being configured to operate independently from the voltage of said electric circuit.
Description
- The present invention relates to an electric switching device for a low voltage circuit having improved characteristics of overcurrent protection.
- As known, electric switching devices used in low voltage electric circuits (that is for applications with nominal voltages up to 1000V AC / 1500V DC), for example circuit breakers, disconnectors, and contactors designated as "switching devices", are all devices designed to ensure the protection of electric circuits and the safety of the users of the electric circuits themselves, by intervening upon the detection of a failure condition.
- Circuit breakers comprise one or more electric poles having at least a moving contact adapted to assume a first position in which it is coupled to a corresponding stationary contact (closed switching device), and a second position, in which it is decoupled from the corresponding stationary contact (open switching device).
- The intervention of the switching devices against the occurrence of fault conditions is carried out through the separation of the moving contacts from the corresponding stationary contacts. As known, the switching devices are generally provided with means adapted to protect against the occurrence of critical differential currents between the poles of the switching devices themselves, caused by an earth leakage current (also known as residual current or imbalance current).
- Furthermore, the switching devices are provided with means adapted to protect against the occurrence of electrical currents having a critical value higher than the nominal operating current; such overcurrents can be non instantaneous (when caused for example by an overload condition), or instantaneous (when caused for example by a short-circuit).
- In the state of the art switching devices of the modular type (miniature circuit breakers) are known that implement, together with the protection against differential currents, the protection from overcurrents by means of magneto-thermal means, and for this reason are known as "residual current circuit breakers with overcurrent protection" (RCBO).
- In particular, the protection from non-instantaneous overcurrents is carried out by a bimetallic element operatively connected to one or more poles, or phases, that are to be protected from overcurrents. In general, the bimetallic element is inserted along the path of the current flowing in a phase of the switching device. When the value of the current flowing through the bimetallic element exceeds a predetermined threshold, the bimetallic element flexes and operatively interacts with the moving contacts of the switching device, so as to cause the separation of the moving contacts themselves from the corresponding stationary contacts. Typically, the predetermined threshold for the current flowing through the bimetallic element is equal to the value of the nominal current plus about 45% of the value itself; further, the flowing of the current must be guaranteed with a tolerance on the nominal operating value equal to about 15%.
- The intervention time necessary to the bimetallic element to open the switching device decreases as the overcurrent passing through it increases, according to a relationship described by a characteristic curve known as "inverse time characteristic curve".
- Even though the bimetallic element fully achieves its intended function and is a particularly economic solution, it implies a number of disadvantages and challenges. In particular, the bimetallic element must be accurately calibrated in order to operate properly according to the current flowing through it. In particular, certain applications do not allow overcurrents that are 20% higher than the nominal operating current, even requiring a tolerance on the nominal operating value equal to about 15%. In this case, the calibration of the bimetallic element in a very narrow range is critical, and results in substantial discards in the production of the switching devices.
- Furthermore, the bimetallic element is a particularly temperature-sensitive device, and therefore requires a compensation of the variations of the room temperature, which may be substantial when the switching device is installed in critical environments.
- The objective of the present invention is to provide a switching device having overcurrent protection means that allow to overcome the disadvantages highlighted in the prior art, while adopting a particularly simple and economical solution.
- Said object is achieved by an electric switching device for a low voltage electric circuit, comprising:
- at least a first pole having at least a first moving contact which can be coupled to/decoupled from a corresponding first stationary contact, and a second pole having at least a second moving contact which can be coupled to/decoupled from a corresponding second stationary contact;
- first detection means adapted to detecting a differential current between the first pole and the second poles, said first detection means being configured to operate independently from the voltage of the electric circuit.
- The switching device comprises second detection means which are adapted to detect an overcurrent flowing in at least one of said first and second poles, and which comprise at least a current transformer operatively connected to said at least one of the first and second poles. The switching device according to the present invention will be described hereinafter by making reference to one of its embodiments as a miniature differential circuit breaker (of the modular type) provided with protection against overcurrent. The principles and technical solutions described in the course of the following description are to be understood in any event to be also valid for different types of switching device, such as for example molded case circuit breakers (MCCB).
- Characteristics and advantages will become more apparent from the description of preferred, but not exclusive, embodiments of a switching device according to the present invention, as illustrated for exemplification purposes in the accompanying drawings; wherein:
-
figure 1 schematically shows a switching device according to the present invention; -
figure 2 shows a block diagram of the electronic means for the overcurrent protection and used in the switching device offigure 1 ; -
figure 3 shows a block diagram of a circuit block used in a switching device according to the present invention (comprising the electronic means for the protection from differential currents and the electronic means for the protection from overcurrent); -
figure 4 illustrates a characteristic curve showing the dependence of an intervention time on the value of the overcurrent against which the intervention is required; -
figure 5 schematically shows a current transformer having a magnetic core with an air gap, used in a switching device according to the present invention. -
Figure 1 schematically illustrates acircuit breaker 1 for a low voltage circuit, in particular aminiature circuit breaker 1, comprising afirst pole 2 and asecond pole 3. Thefirst pole 2 comprises a first movingcontact 4 which can be coupled to/decoupled from a corresponding firststationary contact 5; in turn, thesecond pole 3 comprises a second moving contact 6 which can be coupled to/decoupled from a corresponding secondstationary contact 7. - The
first pole 2 comprises a firstelectrical terminal 8 and a secondelectrical terminal 9, and thesecond pole 3 comprises a thirdelectrical terminal 10 and a fourthelectrical terminal 11. Suchelectrical terminals first pole 2 and thesecond pole 3 to the electric circuit wherecircuit breaker 1 is installed; in particular, they are adapted to operatively connect a power supply source (LINE) to an electric load (LOAD) of the associated electric circuit, by means of thefirst pole 2 and thesecond pole 3. - It is to be set forth that the
circuit breaker 1 according to the present invention may have a number of poles different than that illustrated in the example infigure 1 . - The first moving
contact 4 and the second moving contact 6 are operatively connected to anoperating mechanism 12 adapted to cause the separation of the first and second movingcontacts 4, 6 from the correspondingstationary contacts operating mechanism 12 is of the type known in the art, and will therefore not be described in detail. - The
circuit breaker 1 comprises first detection means adapted to detect a differential current between thefirst pole 2 and thesecond pole 3. - The first detection means are operatively connected to the first moving
contact 4 and the second moving contact 6 so as to cause the separation of the first and second movingcontacts 4, 6 from the corresponding first and secondstationary contacts first pole 2 and thesecond pole 3 greater than a predetermined intervention threshold, for example 0.03 A. - In particular, the first detection means are configured so as to cause the intervention of the actuating means 30 of
circuit breaker 1. Such actuating means 30, of the type known in the state of the art, are adapted to operatively interact with the first movingcontact 4 and the second moving contact 6 so as to cause the separation of the first and second movingcontacts 4, 6 from the corresponding first and secondstationary contacts - In the example illustrated in
figure 1 , the actuating means 30 are operatively connected to theoperating mechanism 12, so as to cause the operation of theoperating mechanism 12 itself, by means of its intervention. - As illustrated in
figure 1 , the first detection means comprise a differential current transformer 20 (or current summing transformer 20), operatively connected to thefirst pole 2 and thesecond pole 3, so as to generate an electric output signal S1 that depends on the differential current between thefirst pole 2 and thesecond pole 3. - In particular, the
differential current transformer 20 comprises amagnetic core 21 crossed by a part of thefirst pole 2 and a part of thesecond pole 3, which constitute the primary winding of thedifferential current transformer 20. Asecondary winding 22 is wound around themagnetic core 21. - Under normal conditions of operation, the current flowing through the
first pole 2 and the corresponding current flowing through thesecond pole 3 are equal in value; the magnetic fields generated by the two currents cancel each other and no electric signal is generated in thesecondary winding 22. - At the occurrence of a differential current between the
first pole 2 and thesecond pole 3, the unbalance between the current flowing through thefirst pole 2 and the current flowing through thesecond pole 3 generates a magnetic field that induces the electric signal S1 in thesecondary winding 22. The value of the electric signal S1 is indicative of the value of the differential current between thefirst pole 2 and thesecond pole 3. - The first detection means comprise
electronic means 23 which are adapted to receive in input the electric signal S1, and which are configured so as to detect a differential current between thefirst pole 2 and thesecond pole 3 through the electric signal S1. In particular, theelectronic means 23 are configured to compare the electric signal S1 received in input with a predetermined threshold value, so as to detect the presence of a differential current between thefirst pole 2 and thesecond pole 3 that is greater than the predetermined intervention threshold. When such predetermined threshold value is exceeded, theelectronic means 23 are configured so as to output a control signal S2. - Control signal S2 is suitable for causing the intervention of the actuating means 30 on the
operating mechanism 12, providing the actuating means 30 themselves with the energy necessary for their intervention. - In the
circuit breaker 1 according to the present invention, the first detection means (and the corresponding actuating means 30) are configured in order to operate independently from the voltage of the electric circuit wherecircuit breaker 1 itself is installed; that is to say, to operate independently from the voltage applied to the first and thirdelectric terminals electric terminals circuit breaker 1. - In particular, the
electronic means 23 are configured to operate using only the energy associated to the electric signal S1 received in input. In practice, theelectronic means 23 remain inactive, or quiescent, until the electric signal S1 is sent to their input. Preferably, theelectronic means 23 are realized by one or more electronic analog blocks. - Preferably, the
circuit breaker 1 comprises test means 24 operatively connected to the first detection means so as to simulate the generation of a differential current between thefirst pole 2 and thesecond pole 3 that is greater than the predetermined intervention threshold. According to a preferred embodiment, test means 24 comprise a test button which realizes, when pressed, an electric circuit inside thecircuit breaker 1 which is adapted to supply a voltage to a second primary winding 25 wound aroundmagnetic core 21. The current that begins to flow in the secondprimary winding 25 as a result of the application of the voltage, induces a magnetic field suitable for generating the electric signal S1 in thesecondary winding 22. - The
circuit breaker 1 according to the present invention further comprises second detection means adapted to detect an overcurrent flowing in at least one of thefirst pole 2 andsecond pole 3. - Overcurrent must be understood as a current with value exceeding the value of the nominal operating current. Overcurrents can be non-instantaneous (typically with a duration in time in the order of minutes), mainly caused by an overload condition; or can be instantaneous currents, caused for example by a short-circuit failure.
- Second detection means are operatively connected to the first moving
contact 4 and the second moving contact 6, so as to cause the separation of the first and second movingcontacts 4, 6 themselves from the corresponding first and secondstationary contacts circuit breaker 1, the same actuating means 30 driven by the first detection means as previously described. - In this way, the same actuating means 30 are advantageously used to actuate both the protection against differential currents and overcurrents; alternatively, the second detection means can drive actuating means dedicated only to the protection against overcurrent, separated from the actuating means 30 dedicated only to the protection against differential currents.
- The second detection means comprise at least a
current transformer 50 operatively connected to thefirst pole 2 and/or thesecond pole 3 so as to output an electric signal S3 depending on the current flowing in thefirst pole 2 or in thesecond pole 3. - In the
circuit breaker 1 illustrated infigure 1 , thefirst pole 2, orphase 2 of thecircuit breaker 1, is protected against overcurrent by means of thecurrent transformer 50. Thesecond pole 3, or neutral 3, is without acurrent transformer 50; protection against overcurrent for thesecond pole 3 is in fact implemented indirectly by means of thecurrent transformer 50 of thefirst pole 2, since that the first detection means guarantee equality between the current flowing through thefirst pole 2 and thesecond pole 3, with the exception of a differential current smaller than the predetermined intervention threshold. - Alternatively, both the first pole and
second poles phases circuit breaker 1 protected against overcurrents by means of a firstcurrent transformer 50 and a secondcurrent transformer 50, respectively. Furthermore, some or all the poles of acircuit breaker 1 with more than two poles may be provided with protection against overcurrent (implemented by means of a respective current transformer 50). For example, atripolar circuit breaker 1 may be configured with three phases, or aquadrupole circuit breaker 1 may be configured with three phases and neutral, or with four phases. - In the
circuit breaker 1 illustrated infigure 1 , thecurrent transformer 50 comprises amagnetic core 51 crossed by a part of thefirst pole 2, which constitutes the primary winding of thecurrent transformer 50 itself. A secondary winding 52 is wound around themagnetic core 51; a magnetic field is generated by a current flowing through thefirst pole 2 so as to induce the electric signal S3 in the secondary winding 52 with a value indicative of the value of the current flowing through thefirst pole 2. - Preferably, the
current transformer 50 is configured so that the electric signal S3 output by means of the secondary winding 52 is in the same order of magnitude as the electric signal S1 output by the differentialcurrent transformer 20, even though the value of the overcurrent flowing through thefirst pole 2 is much greater (many orders of magnitude) than the value of the differential current that may occur between the first pole andsecond poles magnetic core 51 with magnetic permeability sufficiently low to generate the output signal S3 with the same order of magnitude as the output signal S1. - According to a second solution, shown schematically in
figure 5 , thecurrent transformer 50 comprises amagnetic core 510 having anair gap 511 dimensioned so that the electric signal S3 output by means of the secondary winding 52 is in the same order of magnitude as the output signal S1. The use of themagnetic core 510 further simplifies the manufacturing process of thecircuit breaker 1, since the electric conductors that realize a portion of the conduction path of thefirst pole 2 may be first inserted into thecircuit breaker 1 and soldered to the respectiveelectric terminals first pole 2. Thereafter, themagnetic core 510 is placed around a corresponding part of an electric conductor of thefirst pole 2 by inserting such part into themagnetic core 510 through theair gap 511. - The second detection means comprise
electronic means 53 adapted to receive in input the electric signal S3 output by thecurrent transformer 50 and which are configured to detect an overcurrent flowing through thefirst pole 2, using the electric signal S3. In particular, the electronic means 53 are configured to compare the electric signal S3 received in input, preferably adjusted by means of an input block, with a predetermined threshold value, so as to detect the presence of an overcurrent greater than the predetermined intervention threshold. - If such predetermined threshold value is exceeded, the electronic means 53 are configured to output a control signal S4.
- Control signal S4 is suitable for causing the intervention of the actuating means 30, which actuate the
operating mechanism 12, supplying to the actuating means 30 themselves the energy necessary for intervening. Alternatively, the signal S4 may be sent to other actuating means, dedicated only to protecting against overcurrent. - The second detection means are preferably also configured to operate independently from the voltage of the electric circuit where the
circuit breaker 1 is installed. In particular, the electronic means 53 are configured to operate using only the energy of the electric signal S3 receive in input. In practice, the electronic means 53 remain inactive or quiescent until the electric signal S3 is sent to their input. - Such solution is advantageous since that the
electronic means 53 may be implemented in a simple manner, without the provision for thecircuit breaker 1 to have means suitable for drawing the voltage between the first pole andsecond pole electronic means 53. - According to a preferred embodiment, the electronic means 53 comprise a chain of electronic analog blocks.
- Alternatively, the functionalities of the electronic analog blocks may be implemented with a digital electronic unit, such as an electronic processing unit, for example a micro-controller.
- According to this solution, the
current transformer 50 is configured to output the electric signal S3 with sufficient energy to supply the digital electronic unit; an overcurrent flowing in thefirst pole 2 has a high value and therefore owns the necessary energy to generate an electric signal S3 at the output oftransformer 50 suitable for supplying the digital electronic unit. - Preferably, the electronic means 53 are configured so that the delay time between the receiving in input of the electric signal S2 and the outputting of the control signal S4 decreases as the value of the detected overcurrent increases. In particular, the dependence of the delay time on the value of the detected overcurrent is described by a characteristic curve with a decreasing trend (inverse time characteristic curve).
- The delay in the generation of the control signal S4 produces a delay in the intervention of the actuating means 30 on the
operating mechanism 12 for causing the separation of the first and second movingcontacts 4, 6 from the respective first and secondstationary contacts first pole 2 that are only slightly higher than the predetermined intervention threshold are therefore allowed also for long times, while overcurrents with increasing values are allowed for shorter times. - According to a first embodiment, the electronic means 53 are configured to implement only the protection from non-instantaneous overcurrents, which are mainly caused by overload conditions. Thus, the electronic means 53 can be implemented according to simple design specifications.
-
Figure 4 shows, for an exemplary but not limiting purpose, an inverse timecharacteristic curve 500 which describes the trend of the intervention time associated to the electronic means 53 configured to implement the protection from non instantaneous overcurrent; such inverse timecharacteristic curve 500 describes the intervention time of a bimetallic element, used in the prior art for the protection against non instantaneous overcurrent. In practice, the electronic means 53 are configured to simulate the intervention of the bimetallic element against currents caused by overload conditions. - According to such first embodiment, the
circuit breaker 1 comprises, in addition to the actuating means 30, at least a release actuator 32 (of the type known in the prior art) connected to one or more poles of the circuit breaker itself, in such a way that the current that flows through the poles themselves (or a portion of said current) also flows through it. In particular, therelease actuator 32 is inserted along the path of therespective phase 2 of thecircuit breaker 1 and is configured to act on theoperating mechanism 12 upon the occurrence of an instantaneous overcurrent, so as to cause the separation of the first and second movingcontacts 4, 6 from the respective first and secondstationary contacts - In the
circuit breaker 1 illustrated infigure 1 is schematically depicted anelectromagnetic release actuator 32 inserted along the conduction path of thefirst pole 2 of thecircuit breaker 1. - According to a second embodiment, the electronic means 53 are configured to implement, in addition to the protection against non-instantaneous overcurrent, also the protection against instantaneous overcurrent, which are mainly due to short-circuit faults. In particular, the electronic means 53 must be configured so that the time delay between the detection of the instantaneous overcurrent and the generation in output of the control signal S4 is sufficiently short to guarantee an effective intervention against an instantaneous type event.
- In practice the electronic means 53 have the advantage of being configured to also simulate the intervention of the
electromagnetic actuator 32 against an instantaneous overcurrent, and therefore the presence of theelectromagnetic actuator 32 incircuit breaker 1 is not necessary. The described solution is particularly advantageous for applications where the predetermined intervention threshold against an instantaneous overcurrent is not much greater than the predetermined intervention threshold for non-instantaneous overcurrent; for example, reference can be made to an application where the intervention threshold against an instantaneous overcurrent is equal to twice the value of the nominal operating current. - Such applications avoid the use of
electromagnetic actuators 32 for intervening against instantaneous overcurrent, while not placing an excessive burden on the design specifications of theelectronic means 53. - A non-limiting example of the
electronic means 53, which can be used in thecircuit breaker 1 according to the present invention, is described in detail by making reference to the block diagram illustrated infigure 2 . The electronic means 53 infigure 2 comprise a chain of threecircuit blocks first block 54, orinput block 54, receives in input the electric signal S3 output by thecurrent transformer 50, and comprises an adjustment circuit having preferably simple electronic elements such as diodes, resistors, and capacitors; the adjustment circuit is configured to conveniently adjust the electric signal S3. - The adjusted electric signal S3 is sent from the
input block 54 to thesecond circuit block 55, orenergy accumulation block 55, which comprises electronic means to accumulate the energy associated to the adjusted electric signal S3. Thethird circuit block 56, oroutput block 56, is connected to theenergy accumulation block 55 and comprises a comparison device, preferably a voltage detector, which receives in input the energy accumulated in theenergy accumulation block 55 in order to compare the value of the adjusted electric signal S3 to a predetermined threshold value. - The
output block 56 is configured to output the energy received from the energy accumulation block 55 (thus outputting the control signal S4 for the actuating means 30), when the energy received in input corresponds to a value of the adjusted electric signal S3 greater than the predetermined threshold of the comparator device. - The
input block 54 is designed so that the adjusted electric signal S3 is greater than the threshold of the comparator device of theoutput block 56 when an overcurrent flowing through thefirst pole 2 of thecircuit breaker 1 is greater than the predetermined intervention threshold. - It is to be set forth that the energy output by the
energy accumulation block 55 reaches the predetermined threshold for generating control signal S4 faster for larger values of the adjusted electric signal S3. In this way, the time delay between the application of electric signal S3 at theinput block 54 and the generation of the control signal S4 atoutput block 56 decreases as the value of the electric signal S3 increases, and thus such time delay decreases as the value of the detected overcurrent increases. - Advantageously according to a preferred embodiment, the electronic means 23 of the first detection means and the electronic means 53 of the second detection means operate in parallel in the same circuit block 100 (depicted schematically in
figure 1 ), sharing at least an output block of thecircuit block 100 itself. -
Figure 3 illustrates a non-limiting example of thecircuit block 100, wherein the electronic means 23 for the protection against differential current and the electronic means 53 shown infigure 2 are present; suchelectronic means output block 56. - In practice the electronic means 23 realize a first processing branch for the electric signal S1 received in input, while the second electronic means 53 realize a second processing branch for the electric signal S3 received in input. The first and second processing branches operate in parallel independently to generate the control signal S2 and the control signal S4 by means of the
same output block 56 of the circuit block. - In particular, the electronic means 23 comprise at least a circuit block for adjusting the electric signal S1; said adjustment block is designed so that the adjusted signal S1 exceeds the threshold of the comparator device of
output block 56 when the differential current present between the first pole andsecond poles - Preferably, the
circuit breaker 1 comprises test means 57 operatively connected to the second detection means in order to simulate the occurrence of an overcurrent greater than the predetermined intervention threshold. According to a preferred embodiment, the test means 57 comprise a test button which, as a result of being activated, realizes an electric circuit inside thecircuit breaker 1 adapted to apply a voltage to a second primary winding 58 wound around themagnetic core 51. The current that begins to flow in the second primary winding 58 as a result of the application of the voltage induces a magnetic field suitable for generating the electric signal S3 in the first secondary winding 52. - In practice it has been observed that the
circuit breaker 1 according to the present invention fully achieves the pre-established objectives. The protection from overcurrent, and in particular from non-instantaneous overcurrent caused by an overload, is carried out by using thecurrent transformer 50 which, unlike a bimetallic element, does not need to be calibrated and functions substantially independently of environmental temperature. - Furthermore, where provided for, the
current transformer 50 is also used to protect against instantaneous overcurrent caused by short-circuit faults, avoiding the use of electromagnetic actuators dedicated to protecting against short-circuit current. - The solution described is particularly simple and economical to implement. For example, the use of the same actuating means 30 to implement the protection against differential current and overcurrent, as well as the fact of implementing the
electronic means 23 and the electronic means 53 in thesame circuit block 100, as the branches that operate in parallel sharing at least the output block ofcircuit block 100 itself, allow to optimize the available resources in order to obtain a particularly simple and economical solution. - The solutions described here may be subjected to various modifications and variants, all of which are within the scope of the present invention. For example, it must be pointed out that unlike the example illustrated in
figure 1 , theelectronic means 23 and theelectronic means 53 may belong to two completely separate circuit blocks; and/or the actuating means controlled by theelectronic means 23 and theelectronic means 53 may be different.
Claims (13)
- An electric switching device (1) for a low voltage electric circuit, comprising:- at least a first pole (2) having at least a first moving contact (4) which can be coupled to/decoupled from a corresponding first stationary contact (5), and a second pole (3) having at least a second moving contact (6) which can be coupled to/decoupled from a corresponding second stationary contact (7);- first detection means adapted to detect a differential current between said first and second poles (2, 3), said first detection means being configured to operate independently from the voltage of said electric circuit;
characterized in that it comprises second detection means which are adapted to detect an overcurrent flowing in at least one of said first and second poles (2, 3), and which comprise at least a current transformer (50) operatively connected to said at least one of said first and second poles (2, 3). - The switching device (1) according to claim 1, characterized in that said second detection means are configured to operate independently from the voltage of said electric circuit.
- The switching device (1) according to one or more of the preceding claims, characterized in that said second detection means comprise first electronic means (53) which are adapted to receive in input an electric signal (S3) output by the current transformer (50) and which are configured so as to detect said overcurrent using said output electric signal (S3).
- The switching device (1) according to claim 3, characterized in that it comprises actuating means (30) adapted to operatively interact with said first and second moving contacts (4, 6) so as to cause the separation of said first and second moving contacts (4, 6) from the corresponding first and second stationary contacts (5, 7), said first electronic means (53) being configured to output a control signal (S4) adapted to control the intervention of said actuating means (30) to cause the separation of said first and second moving contacts (4, 6) from the corresponding first and second stationary contacts (5, 7) when the detected overcurrent exceeds a predetermined threshold.
- The switching device (1) according to claim 4, characterized in that said first electronic means (53) are configured to operate using the energy associated with the output signal (S3) of the current transformer (50).
- The switching device (1) according to one or more of the preceding claims, characterized in that said at least a current transformer (50) comprises a magnetic core (510) having at least an air gap (511).
- The device according to claim 5, characterized in that said first electronic means (53) comprise at least a digital electronic unit adapted to be supplied by said output signal (S3) of the current transformer (50).
- The switching device (1) according to one or more of the preceding claims, characterized in that said first electronic means (53) are configured so that the delay time that elapses between the receiving in input of said electric signal (S3) output by the current transformer (50) and the outputting of the control signal (S4) decreases when the value of the detected overcurrent increases.
- The switching device (1) according to one or more of the preceding claims, characterized in that it comprises at least a trip actuator (32) connected to said at least one of said first and second poles (2, 3), said trip actuator (32) being operatively connected to said first and second moving contacts (4, 6) so as to cause the separation of said first and second moving contacts (4, 5) from the corresponding first and second stationary contacts (5, 7) following the occurrence of an instantaneous overcurrent.
- The switching device (1) according to one or more of the preceding claims, characterized in that it comprises test means (57) operatively connected to said second detection means so as to simulate the occurrence of said overcurrent.
- The switching device (1) according to one or more of the preceding claims, characterized in that said first detection means are configured so as to control the intervention of said actuating means (30) to cause the separation of said first and second moving contacts (4, 6) from the corresponding first and second stationary contacts (5, 7) following the detection of a differential current between said first and second poles (2, 3) exceeding a predetermined threshold.
- The switching device (1) according to claim 11, characterized in that said first detection means comprise:- a differential current transformer (20) operatively connected to said first and second poles (2, 3);- second electronic means (23) which are adapted to receive in input an electric signal (S1) output by the differential current transformer (20) and which are adapted to detect said differential current between said first and second poles (2, 3) using said output electric signal (S1);
said second electronic means (23) being configured to output a control signal (S2) adapted to control the intervention of said actuating means (30) to cause the separation of said first and second moving contacts (4, 6) from the corresponding first and second stationary contacts (5, 7) when the detected differential current exceeds the predetermined threshold. - The switching device (1) according to claim 12, characterized in that said second electronic means (23) and said first electronic means (53) operate in parallel in a same circuit block (100) sharing at least one output block (56) of said circuit block (100).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT000010A ITBG20110010A1 (en) | 2011-04-06 | 2011-04-06 | ELECTRIC SWITCHING DEVICE. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2509092A1 true EP2509092A1 (en) | 2012-10-10 |
EP2509092B1 EP2509092B1 (en) | 2015-08-05 |
Family
ID=44120377
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12162452.2A Not-in-force EP2509092B1 (en) | 2011-04-06 | 2012-03-30 | Electric switching device |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2509092B1 (en) |
IT (1) | ITBG20110010A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3026443A1 (en) * | 2014-11-27 | 2016-06-01 | ABB S.p.A. | An electronic device for measuring a differential current in an electric line. |
EP3764495A4 (en) * | 2018-03-08 | 2021-12-22 | LS Electric Co., Ltd. | Earth leakage breaker and arc detection apparatus attachable/detachable to/from same earth leakage breaker |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3981980A4 (en) * | 2020-08-20 | 2022-04-13 | Shenzhen Carku Technology Co., Limited | Ignition overcurrent protection device, startup power supply device, and ignition overcurrent protection method |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5276416A (en) * | 1991-09-20 | 1994-01-04 | Kabushiki Kaisha Toshiba | Circuit breaker |
EP2256757A1 (en) * | 2009-05-28 | 2010-12-01 | ABB S.p.A. | Current transformer as well as protection device and circuit breaker including such transformer |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2887634B1 (en) * | 2005-06-24 | 2007-08-10 | Schneider Electric Ind Sas | DIFFERENTIAL CURRENT MEASURING DEVICE, TRIGGER MODULE COMPRISING SUCH A MEASURING DEVICE AND CUTTING DEVICE HAVING SUCH A MODULE |
-
2011
- 2011-04-06 IT IT000010A patent/ITBG20110010A1/en unknown
-
2012
- 2012-03-30 EP EP12162452.2A patent/EP2509092B1/en not_active Not-in-force
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5276416A (en) * | 1991-09-20 | 1994-01-04 | Kabushiki Kaisha Toshiba | Circuit breaker |
EP2256757A1 (en) * | 2009-05-28 | 2010-12-01 | ABB S.p.A. | Current transformer as well as protection device and circuit breaker including such transformer |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3026443A1 (en) * | 2014-11-27 | 2016-06-01 | ABB S.p.A. | An electronic device for measuring a differential current in an electric line. |
CN105652065A (en) * | 2014-11-27 | 2016-06-08 | Abb股份公司 | Electronic device for measuring differential current in electric line |
US9651580B2 (en) | 2014-11-27 | 2017-05-16 | Abb S.P.A. | Electronic device for measuring a differential current in an electric line |
CN105652065B (en) * | 2014-11-27 | 2019-11-15 | Abb股份公司 | For measuring the electronic equipment of the difference current in electric wire |
EP3764495A4 (en) * | 2018-03-08 | 2021-12-22 | LS Electric Co., Ltd. | Earth leakage breaker and arc detection apparatus attachable/detachable to/from same earth leakage breaker |
Also Published As
Publication number | Publication date |
---|---|
EP2509092B1 (en) | 2015-08-05 |
ITBG20110010A1 (en) | 2012-10-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU2009214807B2 (en) | A Residual-Current Circuit Breaker | |
US20120249151A1 (en) | Residual-current circuit breaker | |
CA2792103C (en) | Electrical switching apparatus with overvoltage protection | |
IL194203A (en) | Switching device with a line voltage independent tripping device and a line voltage dependent tripping device | |
AU2011239222B2 (en) | Electric switching device | |
CN107238749B (en) | Differential current sensor | |
US20150194798A1 (en) | Electrical fault protection device | |
KR20150084048A (en) | Automatic circuit breaker with auxiliary short circuit | |
KR101261496B1 (en) | Circuit for smart-earthing using permanent magnetic actuator | |
EP2509092B1 (en) | Electric switching device | |
EP2136383B1 (en) | A control device for an automatic reset apparatus | |
WO2018099902A1 (en) | A modular system for protecting an electrical circuit | |
US8749941B2 (en) | Residual-current circuit breaker | |
CN111834170A (en) | Compact protection switch device | |
CN110506376B (en) | Electrical switching apparatus | |
GB2566059A (en) | A system for protecting an electrical circuit | |
EP3255648B1 (en) | Compact control module for automatic reset devices | |
AU2019447727B2 (en) | Electric line (L) protection device for detecting a leakage fault, a short-circuit, fault, an overcurrent fault and an arc fault | |
Fidigatti et al. | Effect of harmonic pollution on low voltage overcurrent protection | |
EP1734632B1 (en) | Safety device for a circuit breaker | |
JP5137226B2 (en) | Circuit breaker | |
GB2580206A (en) | Protective switching device for a low-voltage circuit for identifying series arcing faults | |
JP5424362B2 (en) | Residential distribution board | |
CN118020135A (en) | Protective switching device | |
RU126527U1 (en) | PROTECTIVE SHUT-OFF DEVICE |
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 |
|
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 |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
17P | Request for examination filed |
Effective date: 20130404 |
|
17Q | First examination report despatched |
Effective date: 20140107 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: H01H 71/12 20060101ALN20150212BHEP Ipc: H01H 83/22 20060101AFI20150212BHEP |
|
INTG | Intention to grant announced |
Effective date: 20150227 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
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: AT Ref legal event code: REF Ref document number: 741118 Country of ref document: AT Kind code of ref document: T Effective date: 20150815 |
|
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: 602012009259 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 741118 Country of ref document: AT Kind code of ref document: T Effective date: 20150805 |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG4D |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MP Effective date: 20150805 |
|
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: 20151106 Ref country code: NO 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: 20151105 Ref country code: LV 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: 20150805 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: 20150805 Ref country code: FI 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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: PL 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: 20150805 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: 20150805 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: 20150805 Ref country code: SE 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: 20150805 Ref country code: PT 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: 20151207 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: 20151205 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: 20150805 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: 20150805 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 5 |
|
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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SK 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: 20150805 Ref country code: EE 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: 20150805 Ref country code: DK 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: 20150805 Ref country code: CZ 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: 20150805 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602012009259 Country of ref document: DE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: RO 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: 20150805 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20160509 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SI 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: 20150805 Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MC 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: 20150805 Ref country code: LU 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: 20160330 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20160330 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: MM4A |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BE 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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160330 Ref country code: IE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160330 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 6 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MT 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: 20150805 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 7 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CY 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: 20150805 Ref country code: HU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO Effective date: 20120330 Ref country code: SM 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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MT 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: 20160331 Ref country code: TR 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: 20150805 Ref country code: MK 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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BG 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: 20150805 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AL 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: 20150805 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20190321 Year of fee payment: 8 Ref country code: IT Payment date: 20190325 Year of fee payment: 8 Ref country code: FR Payment date: 20190322 Year of fee payment: 8 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 602012009259 Country of ref document: DE Representative=s name: KUHNEN & WACKER PATENT- UND RECHTSANWALTSBUERO, DE Ref country code: DE Ref legal event code: R081 Ref document number: 602012009259 Country of ref document: DE Owner name: ABB SCHWEIZ AG, CH Free format text: FORMER OWNER: ABB S.P.A., MILANO, IT |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 602012009259 Country of ref document: DE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20201001 Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20200331 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20200330 |