CA1203284A - Hybrid current sensor - Google Patents
Hybrid current sensorInfo
- Publication number
- CA1203284A CA1203284A CA000409402A CA409402A CA1203284A CA 1203284 A CA1203284 A CA 1203284A CA 000409402 A CA000409402 A CA 000409402A CA 409402 A CA409402 A CA 409402A CA 1203284 A CA1203284 A CA 1203284A
- Authority
- CA
- Canada
- Prior art keywords
- terminals
- current
- frequency
- current sensor
- compensating circuit
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase AC
- H01F38/28—Current transformers
- H01F38/32—Circuit arrangements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase AC
- H01F38/28—Current transformers
- H01F38/30—Constructions
- H01F2038/305—Constructions with toroidal magnetic core
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
- Transformers For Measuring Instruments (AREA)
Abstract
Abstract.-HYBRID CURRENT SENSOR.
The invention relates to a hybrid current sensor generating a measuring and supply combined signal for a solid state circuit interruption initiating device. A load resistance is connected to the secondary winding output terminals and the core of the sensor comprises an air-gap of prede-termined length e. The sensor is of hybrid type having a secondary time constant comprised between 10 microseconds and 100 milliseconds.
The invention relates to a hybrid current sensor generating a measuring and supply combined signal for a solid state circuit interruption initiating device. A load resistance is connected to the secondary winding output terminals and the core of the sensor comprises an air-gap of prede-termined length e. The sensor is of hybrid type having a secondary time constant comprised between 10 microseconds and 100 milliseconds.
Description
3~
The invention relates to a current sensor for electroni-cally ~easuring ~nd/or protective equipment intended to control the ~urrent in a line of an electrical energy supply system, and comprising a secondary winding uound about a core, so as to generate a measuring and supply combined secondary signal of which the value depends on the primary current intensity flowing in the line.
According to a known device of the mentioned type, the sensor includes a conventional current transformer of whicil the secondary ~inding is capable of producing an electrical power. A current transformer coupled to elec-tro-nically equipment generally requires a large number of turns which causes, especial]y if the over-all dimensions are limited, a temperature rise capable of disturbing the performance of the coupled electronically equipment when this last one is close to the current transformer. The high cost of manufacturing and the large over-all dimensions of such a conventional transformer constitute additional dis-advantages.
Other known current sensors of amagnetic type or with an air-gap magnetic circuit comprises a secondary winding in-ducing an output voltage proportional to the derivative of primary current. This voltage is applied- to a high input impedance integratin(~ circuit. This type of sensor in dt-does not induce a temperature rise, but it generally re-quires a supply auxiliary source of the performance of the coupled active integrating circu~t~
An object of the invention is to remedy to these disadvan-tages and to realize an improved inductive current sensor capable of generating a predetermined secondary power, with a reduced temperature rise and without any supply auxiliary source for the power supply of electronic equipment.
t According to the present invention, there is provided a hybrid current sensor for electronical.ly measuring and/or protective equipment, more particula.rly a circuit breaker having a static trip device, intended to control the current in a line of an electrical energy supply system, said current sensor being inductive, being coupled with the line, and comprising:
- a magnetic circuit or core coupled to said line and having a reluctance Re and at least one air-gap of predetermined length, - a secondary winding having output terminals, having n turns wound about said core, and having an ohmic resistance Rl, - a load resistance connected electrically to the output terminals of said secondary winding and having an ohmic resistance R2, so that the hybrid inductive sensor i5 provided with a secondary time constant which is defined by the relation n2 having a value comprised Re (R~ + R2) between 10 microseconds and 100 milliseconds, - the total length of said core air-gap being advantageously comprised between 0.5 and 20 millimeters, and the ohmic resistance R2 value in the neighbourhood of 10 to 1000 ohms, - a frequency compensating circuit electricall.y connected to terminals of the load resistance so as to generate a measuring output signal having an amplitude which is almost constant when a primary current frequency flowing in the line is comprised in a predetermined bracket about a compensation central frequency, - said trip device having an electronic processing system generating a tripping order to a circuit breaker operation coil when said output signal of said frequency compensating circuit exceeds a predetermined threshold, 32~3~
the supply o said processing system being carried out by means of a non compensated voltaye taken between the load xesistance terminals.
Other advantages and technical data will appear more clearly from the following non restrictive description of preferred embodiments of the invention, wherein reference i5 made to the accompanying drawings, in which:
.
~ - 2a -Fig. 1 is a schematic view of a toroidal hybrid current sen-sor according to the invention;
Fig9 2 illustrates two representative graphs of the output current I2 modulus (strong lines) and of the phase shift (dotted lines~, as a function of the secondary t~me constant t2 of the sensor according to fig. 1, the primary current I1 frequency f being 50 Hz;
Figs. 3 and 4 are two realization variants of the current senSor according to fig. 1;
Fig. 5 represents the equivalent scheme of a hybrid sensor accordiny to figs. 2 through 4, equipped ~ h a frequency compensation circuit;
Fig. 6 is a partial view of Fig~ 5 and sho\~s a variant of the fre~uency compensation circuit;
The invention relates to a current sensor for electroni-cally ~easuring ~nd/or protective equipment intended to control the ~urrent in a line of an electrical energy supply system, and comprising a secondary winding uound about a core, so as to generate a measuring and supply combined secondary signal of which the value depends on the primary current intensity flowing in the line.
According to a known device of the mentioned type, the sensor includes a conventional current transformer of whicil the secondary ~inding is capable of producing an electrical power. A current transformer coupled to elec-tro-nically equipment generally requires a large number of turns which causes, especial]y if the over-all dimensions are limited, a temperature rise capable of disturbing the performance of the coupled electronically equipment when this last one is close to the current transformer. The high cost of manufacturing and the large over-all dimensions of such a conventional transformer constitute additional dis-advantages.
Other known current sensors of amagnetic type or with an air-gap magnetic circuit comprises a secondary winding in-ducing an output voltage proportional to the derivative of primary current. This voltage is applied- to a high input impedance integratin(~ circuit. This type of sensor in dt-does not induce a temperature rise, but it generally re-quires a supply auxiliary source of the performance of the coupled active integrating circu~t~
An object of the invention is to remedy to these disadvan-tages and to realize an improved inductive current sensor capable of generating a predetermined secondary power, with a reduced temperature rise and without any supply auxiliary source for the power supply of electronic equipment.
t According to the present invention, there is provided a hybrid current sensor for electronical.ly measuring and/or protective equipment, more particula.rly a circuit breaker having a static trip device, intended to control the current in a line of an electrical energy supply system, said current sensor being inductive, being coupled with the line, and comprising:
- a magnetic circuit or core coupled to said line and having a reluctance Re and at least one air-gap of predetermined length, - a secondary winding having output terminals, having n turns wound about said core, and having an ohmic resistance Rl, - a load resistance connected electrically to the output terminals of said secondary winding and having an ohmic resistance R2, so that the hybrid inductive sensor i5 provided with a secondary time constant which is defined by the relation n2 having a value comprised Re (R~ + R2) between 10 microseconds and 100 milliseconds, - the total length of said core air-gap being advantageously comprised between 0.5 and 20 millimeters, and the ohmic resistance R2 value in the neighbourhood of 10 to 1000 ohms, - a frequency compensating circuit electricall.y connected to terminals of the load resistance so as to generate a measuring output signal having an amplitude which is almost constant when a primary current frequency flowing in the line is comprised in a predetermined bracket about a compensation central frequency, - said trip device having an electronic processing system generating a tripping order to a circuit breaker operation coil when said output signal of said frequency compensating circuit exceeds a predetermined threshold, 32~3~
the supply o said processing system being carried out by means of a non compensated voltaye taken between the load xesistance terminals.
Other advantages and technical data will appear more clearly from the following non restrictive description of preferred embodiments of the invention, wherein reference i5 made to the accompanying drawings, in which:
.
~ - 2a -Fig. 1 is a schematic view of a toroidal hybrid current sen-sor according to the invention;
Fig9 2 illustrates two representative graphs of the output current I2 modulus (strong lines) and of the phase shift (dotted lines~, as a function of the secondary t~me constant t2 of the sensor according to fig. 1, the primary current I1 frequency f being 50 Hz;
Figs. 3 and 4 are two realization variants of the current senSor according to fig. 1;
Fig. 5 represents the equivalent scheme of a hybrid sensor accordiny to figs. 2 through 4, equipped ~ h a frequency compensation circuit;
Fig. 6 is a partial view of Fig~ 5 and sho\~s a variant of the fre~uency compensation circuit;
2() Fig. 7 sl1ows the representative diagrams of the output vol-tases U2 and Uc amplitudes of the sensor respectively before and after the compensation, as a function of the frequency f of the primary current I1 to measure;
Fig. 8 represents the application of a compensated hybrid sensor to an electronic device of a protective circuit brea~er operating according to the invent~on.
On fig. 1, the hybrid current scnsor 10 com~rises a magnetic circuit CM toroid shaped and provided with one or several air-gaps 12 of total length e. The magnetic circuit CM is crossed by a line 14 of an alternating current supply net-wor~, the line 14 actlng as a primary winding flowed through by a current I1 to control. A secondary winding 16 is wound about the torns and comprises n turns of ohmic resistance R1. A load resistance R~ is connected to the output termi-nals of the secondary winding. The secondarv time constant t, of the hybrid sensor is defined by the relationRe~R R )~
Re being the total reluctance of the magnetic circuit CM9 ~3~
1he se(ondary windinll 16 pro~:iu~es an output eurrent I~ rc--presentillg a vectvr quant.itv o~ whieh the modulus arld the phase shift ~ with respect to the p-imary eurrent I1 aI~e il1ustlated by the d:ia(1rams on ~ig. 2 dS a funetlon o~ the seeondc.ry time eonstant t2 and for a (~-i.ven fre(luency f of the primdly current T,. The moduius expressed by tl-le ratio n~_ var;es bet~Yeer; O an(:l 1 when the t;me eor1stant t2 inereases. For time constants t2 above 100 m.ilIisecon(ls, l.he sensor is a convent.iona~. urrent transformer. For time constarlts -t2 belo~Y 10 m.icroseconds, the sensor is of ama~ne-tie type. The hybrid sensor occupies the intermediate zorle.
rhe secondary windi.n(~ cross-sec~ion of an induet LVe sensor being proportional ~o '~h(- procluct nI2, it will be noted on fig. 2 that ;t îs the current transformer, where nI2 is ~5 near:Ly equal to I1~ which re4uires the largest volun)e and which is therefore the most expensiYe.
A hybri.d sensor of whiell the tilne constant t2 :is comprised between lO mieroseconds and 100 milliseeonds, requires a eonsiderably reduced seeorldary winding with respeet to an equivalent current trans~ormer. Or again in given overail dimensi.ot1s, between a convent:ional eurrent transformer and a hybrid sensor o-; identical primary rated currents, it is the latter whieh is -the cen~-re of t.he smallest temperature r;se. Conseq~erltly it will sufrice to ehoose the values of the load resistanee R2, the mclgnetic circuit C~l cross-seetion S and the air-gap Iennth e to determ.ine the t, val.ue. Some tests showed l;il~t the total l.en~th c of the ai.r-~aps hacl to be eomr)rise(l het~veerl 0,5 and 20 milli.meters, and the ioad resistance l~2 was between 10 to 1000 ohms aeeordin~ to the rated currerlt I1 intensity flowing in the line 14.
On fi~. 3, the torus with an air-gclp 12 on fig. 1 was re-placed by a rectangular mcl~lletic circuit C~ w;th two air-gaps 12a, 12b, comprising -two U-shaped elementary portions faein~ eaeh other, so as to border a window erossed by the line 14. A s;ngle seeondary winding 16 is wound about the ma~net.le eireuit Cll.
lZ~313~
According to fig. 4, the secondary winding includes two coils 16a~ 16b series or parallel connected? the rest being identical with the sensor on fiy. ~. The relative position o-f coils 16a, 1~b with respect to the air-gaps can be inde-terminate. The characteristics of the hybrid sensor 10accordin~ to figs. 1 through 3 nevertneless ciepend on ~he va~iation of the current I1 frequency to meas~lre. Indeed, the amplitude and the phase of the output volta~3e U2 be-tween the secondary winding 16 terminals vary t~;th thc fre-quency. Therefore a frequency compensating ci~cuit 18(fig. 5) is coupled to -the hybr-id sensor.
The frequency compensating circuit 18 (fig 5) comprises a series circuit RC connected in parallel to the load re-sistance R2 terminals. The image signal of the current I1to measure is the voltage Uc between the capacitor C ~er-minals. The circuit 18 values of R and C are defined by the following relation : 1 RC (2~rfo)2t2 where fO is the compensation centre frequency (55 rlz for example).
~n fi~. 6, the compensating circuit 18 consists of a se-ries circuit with inductance L and resistance R, connected in parallel to the R2 terminals, the image signal of the current I1 measurement being in that case the voltage UR
between the resistance R terminals.
Fig. 7 compares the amplitudes oF the output voltages U2
Fig. 8 represents the application of a compensated hybrid sensor to an electronic device of a protective circuit brea~er operating according to the invent~on.
On fig. 1, the hybrid current scnsor 10 com~rises a magnetic circuit CM toroid shaped and provided with one or several air-gaps 12 of total length e. The magnetic circuit CM is crossed by a line 14 of an alternating current supply net-wor~, the line 14 actlng as a primary winding flowed through by a current I1 to control. A secondary winding 16 is wound about the torns and comprises n turns of ohmic resistance R1. A load resistance R~ is connected to the output termi-nals of the secondary winding. The secondarv time constant t, of the hybrid sensor is defined by the relationRe~R R )~
Re being the total reluctance of the magnetic circuit CM9 ~3~
1he se(ondary windinll 16 pro~:iu~es an output eurrent I~ rc--presentillg a vectvr quant.itv o~ whieh the modulus arld the phase shift ~ with respect to the p-imary eurrent I1 aI~e il1ustlated by the d:ia(1rams on ~ig. 2 dS a funetlon o~ the seeondc.ry time eonstant t2 and for a (~-i.ven fre(luency f of the primdly current T,. The moduius expressed by tl-le ratio n~_ var;es bet~Yeer; O an(:l 1 when the t;me eor1stant t2 inereases. For time constants t2 above 100 m.ilIisecon(ls, l.he sensor is a convent.iona~. urrent transformer. For time constarlts -t2 belo~Y 10 m.icroseconds, the sensor is of ama~ne-tie type. The hybrid sensor occupies the intermediate zorle.
rhe secondary windi.n(~ cross-sec~ion of an induet LVe sensor being proportional ~o '~h(- procluct nI2, it will be noted on fig. 2 that ;t îs the current transformer, where nI2 is ~5 near:Ly equal to I1~ which re4uires the largest volun)e and which is therefore the most expensiYe.
A hybri.d sensor of whiell the tilne constant t2 :is comprised between lO mieroseconds and 100 milliseeonds, requires a eonsiderably reduced seeorldary winding with respeet to an equivalent current trans~ormer. Or again in given overail dimensi.ot1s, between a convent:ional eurrent transformer and a hybrid sensor o-; identical primary rated currents, it is the latter whieh is -the cen~-re of t.he smallest temperature r;se. Conseq~erltly it will sufrice to ehoose the values of the load resistanee R2, the mclgnetic circuit C~l cross-seetion S and the air-gap Iennth e to determ.ine the t, val.ue. Some tests showed l;il~t the total l.en~th c of the ai.r-~aps hacl to be eomr)rise(l het~veerl 0,5 and 20 milli.meters, and the ioad resistance l~2 was between 10 to 1000 ohms aeeordin~ to the rated currerlt I1 intensity flowing in the line 14.
On fi~. 3, the torus with an air-gclp 12 on fig. 1 was re-placed by a rectangular mcl~lletic circuit C~ w;th two air-gaps 12a, 12b, comprising -two U-shaped elementary portions faein~ eaeh other, so as to border a window erossed by the line 14. A s;ngle seeondary winding 16 is wound about the ma~net.le eireuit Cll.
lZ~313~
According to fig. 4, the secondary winding includes two coils 16a~ 16b series or parallel connected? the rest being identical with the sensor on fiy. ~. The relative position o-f coils 16a, 1~b with respect to the air-gaps can be inde-terminate. The characteristics of the hybrid sensor 10accordin~ to figs. 1 through 3 nevertneless ciepend on ~he va~iation of the current I1 frequency to meas~lre. Indeed, the amplitude and the phase of the output volta~3e U2 be-tween the secondary winding 16 terminals vary t~;th thc fre-quency. Therefore a frequency compensating ci~cuit 18(fig. 5) is coupled to -the hybr-id sensor.
The frequency compensating circuit 18 (fig 5) comprises a series circuit RC connected in parallel to the load re-sistance R2 terminals. The image signal of the current I1to measure is the voltage Uc between the capacitor C ~er-minals. The circuit 18 values of R and C are defined by the following relation : 1 RC (2~rfo)2t2 where fO is the compensation centre frequency (55 rlz for example).
~n fi~. 6, the compensating circuit 18 consists of a se-ries circuit with inductance L and resistance R, connected in parallel to the R2 terminals, the image signal of the current I1 measurement being in that case the voltage UR
between the resistance R terminals.
Fig. 7 compares the amplitudes oF the output voltages U2
3~ and Uc before and after the compensation on a function of the current I1 frequency f to measure, the values o-f the time constant t2 and the current I1 intensity being given.
It wlll be noted that the image voltage Uc amplitude is almost constant when the current I1 ~requency f is com-prised in a predetermined braclcet about the compensationcentre frequency fO. Ihe current I1 to measure and the voltage Uc are in phase ~Yhen the current I1 frequency is equal to the centre frequency fO.
lZ~)3;~8~
t~
Fig. 8 represents the application of a cornpensated hybrid sensor according to fi~. 5. The hybrid sensor generates a measuring and supply combined secondary signal to an elec-troni( control equ;pment or static tr~p unit of a current circuit breaker of which one of tlle contacts 20 is lnserted in the line 14. The image signal Uc provided by the cornpen-sating circuit 18 is injectcd into an electronic processing system 22 through a first connection conductor 24. The non compensated ~oltage U2 of the secondary winding 16 will be advantageously utilized for the processing system 22 power supply owing to a second connection conductor 26. When an overload or short-circuit fault appears on the line 14, the processing systern 22 outpu-t generates a tripping order to an operation coil 28 \~hich conven-tionally induces the rnechanism 30 unlock and the switch-off of the protective circuit breaker con-tacts 20.
The frequency compensating circuit 18 o r the hybrid sensor should of course be differently disposed.
It wlll be noted that the image voltage Uc amplitude is almost constant when the current I1 ~requency f is com-prised in a predetermined braclcet about the compensationcentre frequency fO. Ihe current I1 to measure and the voltage Uc are in phase ~Yhen the current I1 frequency is equal to the centre frequency fO.
lZ~)3;~8~
t~
Fig. 8 represents the application of a cornpensated hybrid sensor according to fi~. 5. The hybrid sensor generates a measuring and supply combined secondary signal to an elec-troni( control equ;pment or static tr~p unit of a current circuit breaker of which one of tlle contacts 20 is lnserted in the line 14. The image signal Uc provided by the cornpen-sating circuit 18 is injectcd into an electronic processing system 22 through a first connection conductor 24. The non compensated ~oltage U2 of the secondary winding 16 will be advantageously utilized for the processing system 22 power supply owing to a second connection conductor 26. When an overload or short-circuit fault appears on the line 14, the processing systern 22 outpu-t generates a tripping order to an operation coil 28 \~hich conven-tionally induces the rnechanism 30 unlock and the switch-off of the protective circuit breaker con-tacts 20.
The frequency compensating circuit 18 o r the hybrid sensor should of course be differently disposed.
Claims (3)
1. Hybrid current sensor for electronically measuring and/or protective equipment, more particularly a circuit breaker having a static trip device, intended to control the current in a line of an electrical energy sup-ply system, said current sensor being inductive, being coupled with the line, and comprising:
- a magnetic circuit or core coupled to said line and having a reluctance Re and at least one air-gap of predetermined length, - a secondary winding having output terminals, having n turns wound about said core, and having an ohmic resistance R1, - a load resistance connected electrically to the output terminals of said secondary winding and having an ohmic resistance R2, so that the hybrid inductive sensor is provided with a secondary time constant which is defined by the relation having a value comprised between 10 microseconds and 100 milliseconds, - the total length of said core air-gap being advantageously comprised between 0.5 and 20 millimeters, and the ohmic resistance R2 value in the neighbourhood of 10 to 1000 ohms, - a frequency compensating circuit electrically connected to terminals of the load resistance so as to generate a measuring output signal having an amplitude which is almost constant when a primary current frequency flowing in the line is comprised in a predetermined bracket about a compensation central frequency, - said trip device having an electronic processing system generating a tripping order to a circuit breaker operation coil when said output signal of said frequency compensating circuit exceeds a predetermined threshold, the supply of said processing system being carried out by means of a non compensated voltage taken between the load resistance terminals.
- a magnetic circuit or core coupled to said line and having a reluctance Re and at least one air-gap of predetermined length, - a secondary winding having output terminals, having n turns wound about said core, and having an ohmic resistance R1, - a load resistance connected electrically to the output terminals of said secondary winding and having an ohmic resistance R2, so that the hybrid inductive sensor is provided with a secondary time constant which is defined by the relation having a value comprised between 10 microseconds and 100 milliseconds, - the total length of said core air-gap being advantageously comprised between 0.5 and 20 millimeters, and the ohmic resistance R2 value in the neighbourhood of 10 to 1000 ohms, - a frequency compensating circuit electrically connected to terminals of the load resistance so as to generate a measuring output signal having an amplitude which is almost constant when a primary current frequency flowing in the line is comprised in a predetermined bracket about a compensation central frequency, - said trip device having an electronic processing system generating a tripping order to a circuit breaker operation coil when said output signal of said frequency compensating circuit exceeds a predetermined threshold, the supply of said processing system being carried out by means of a non compensated voltage taken between the load resistance terminals.
2. Current sensor according to claim 1, wherein said frequency compensating circuit comprises a series connection of a resistor and capacitor, and wherein terminals of said capacitor provide said output signal of the frequency compensating circuit.
3. Current sensor according to claim 1, wherein said frequency compensating circuit comprises a series connection of an inductor and resistor, and wherein terminals of said resistor provide said output signal of the frequency compensating circuit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8116416A FR2512264A1 (en) | 1981-08-26 | 1981-08-26 | COMPENSATED HYBRID CURRENT SENSOR |
| FR8116416 | 1981-08-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1203284A true CA1203284A (en) | 1986-04-15 |
Family
ID=9261728
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000409402A Expired CA1203284A (en) | 1981-08-26 | 1982-08-13 | Hybrid current sensor |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0074297B2 (en) |
| JP (1) | JPS5895266A (en) |
| CA (1) | CA1203284A (en) |
| DE (1) | DE3267597D1 (en) |
| FR (1) | FR2512264A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5495169A (en) * | 1984-10-12 | 1996-02-27 | Smith; Dayle | Clamp-on current sensor |
| FR2603992B1 (en) * | 1986-09-16 | 1988-10-28 | Alsthom | DEVICE FOR THE DIGITAL ACQUISITION OF AN ALTERNATIVE ELECTRIC CURRENT FROM A CURRENT TRANSFORMER WITH SATURABLE MAGNETIC CORE |
| DE3701779A1 (en) * | 1987-02-13 | 1988-08-04 | Budapesti Mueszaki Egyetem | AS A CURRENT TRANSFORMER, LINEAR TRANSMITTER |
| JPH01122735A (en) * | 1987-11-06 | 1989-05-16 | Nissan Motor Co Ltd | Constant speed running device |
| FR2752996B1 (en) * | 1996-09-05 | 1998-10-02 | Schneider Electric Sa | CURRENT TRANSFORMER AND PROTECTION RELAY COMPRISING SUCH A TRANSFORMER |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR514999A (en) * | 1916-01-10 | 1921-03-22 | Siemens Schuckertwerke Gmbh | Current transformer whose load includes a capacitor in order to compensate for the wattage current |
| DE535000C (en) * | 1928-08-11 | 1931-10-05 | Elek Zitaets Act Ges Vorm W La | Resonance circuit |
| FR833139A (en) * | 1937-03-02 | 1938-10-12 | Siemens Ag | Ring-core current transformer for measuring high frequency currents |
| FR1142618A (en) * | 1956-02-09 | 1957-09-20 | Telemecanique Electrique | Method and device for measuring high intensities |
| CH350710A (en) * | 1956-11-09 | 1960-12-15 | Bbc Brown Boveri & Cie | Current transformer system for high voltage systems |
| DE1281545B (en) * | 1963-05-29 | 1968-10-31 | Siemens Ag | Iron core converter with air gap for current measurement |
-
1981
- 1981-08-26 FR FR8116416A patent/FR2512264A1/en active Granted
-
1982
- 1982-08-13 DE DE8282401529T patent/DE3267597D1/en not_active Expired
- 1982-08-13 CA CA000409402A patent/CA1203284A/en not_active Expired
- 1982-08-13 EP EP19820401529 patent/EP0074297B2/en not_active Expired
- 1982-08-25 JP JP57146324A patent/JPS5895266A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0074297A1 (en) | 1983-03-16 |
| FR2512264B1 (en) | 1983-10-28 |
| EP0074297B1 (en) | 1985-11-21 |
| FR2512264A1 (en) | 1983-03-04 |
| JPS5895266A (en) | 1983-06-06 |
| JPH0447271B2 (en) | 1992-08-03 |
| DE3267597D1 (en) | 1986-01-02 |
| EP0074297B2 (en) | 1988-12-07 |
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