EP0386319A2 - Magnetic DC to DC converter with reduced temperature drift - Google Patents
Magnetic DC to DC converter with reduced temperature drift Download PDFInfo
- Publication number
- EP0386319A2 EP0386319A2 EP89119759A EP89119759A EP0386319A2 EP 0386319 A2 EP0386319 A2 EP 0386319A2 EP 89119759 A EP89119759 A EP 89119759A EP 89119759 A EP89119759 A EP 89119759A EP 0386319 A2 EP0386319 A2 EP 0386319A2
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- European Patent Office
- Prior art keywords
- converter
- hall
- voltages
- magnetic
- current
- 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.)
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- 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
- H01F38/40—Instruments transformers for dc
Definitions
- the innovation relates to a magnetic direct current converter for detecting direct currents in a current conductor with a large cross section, through which a direct current with high values, in particular those that occur briefly and in a burst-like manner, flows.
- the magnetic DC converter is heated up to 130 ° C. Compared to an assumed, for example, ambient temperature of approx. 25 ° C
- the innovation is based on the object of specifying a magnetic direct current converter for detecting direct currents, the temporary and sudden increase to high values of which may result in considerable heating of the direct current converter.
- the object is achieved with the DC converter specified in the protection claim.
- the magnetic DC converter according to the invention consists of a magnetic core MK through which a current conductor SL with a large cross section is passed.
- the current conductor SL is designed in the form of a rectilinear and rigid busbar carrying the direct current I L.
- the magnetic core MK is not closed in a ring, son has an air gap LS.
- at least two Hall generators HG1, HG2, which are arranged antiparallel to one another and are connected in a thermally conductive manner to the magnetic core MK, are inserted. Both Hall generators are supplied in a known manner from a supply voltage, not shown, via connecting lines, also not shown.
- the Hall voltages U H (HG1), U H (HG2) of the two mall generators are fed to an evaluation circuit AS belonging to the DC converter.
- This preferably forms the difference between the Hall voltages by means of a known differential amplifier circuit and makes this available as a measurement signal ⁇ U H at the output of the DC converter.
- the two Hall generators HG1, HG2 are distinguished by the fact that their zero point offset voltages U N (T) HG1 , U N (T) HG2 , ie the voltages caused at the output of the generators without a magnetic field solely due to the supply voltages, have an identical temperature profile . Hall generators, the zero point offset voltages of which differ greatly from one another due to the usual specimen variations, are not suitable according to the innovation to be used antiparallel in the air gap of the magnetic core of the DC converter.
- the new DC converter according to the invention has the particular advantage that, on the one hand, the level of the evaluable differential Hall voltage ⁇ U H at the output is twice as high due to the subtraction of the two signed different Hall voltages U H of the antiparallel generators than when using a single Hall generator.
- This subtraction of the Hall voltages from an antiparallel Hall generator having an identical temperature profile for the zero point offset voltages has the further advantage that these temperature profiles are almost identical fully compensate. This is further explained with reference to FIG 2.
- the two temperature profiles of the zero point offset voltages U N (T) HG1 , U N (T) HG2 of the two antiparallel mall generators entered in FIG. 2 differ only slightly from one another in accordance with the innovation. They therefore have gradients with identical signs and approximately the same values.
- the zero point offset voltage U N (T0) HG2 of the Hall generator HG2 has the relatively large value lying between the minimum and maximum values U NMI , U NMA caused by the sample scatter.
- the Hall voltages at the output of the anti-parallel generators are subtracted from each other, the zero point offset voltage in the converter output signal ⁇ U H is reduced to the almost vanishing, lying between the curves U N (T) HG1 and U N (T) HG2 at the temperature zero point T0 Value U N (T0) HG2 - HG1 .
- Such a shift is possible in a known manner by means of circuitry measures in the evaluation circuit AS.
- FIG 2 is the example of U * N (HG2) such a shifted temperature profile for the Hall generator HG2 is shown in broken lines.
- the new DC converter according to the invention can be used particularly advantageously when the DC current I L through the current conductor SL can on the one hand take on very high values for a short time and suddenly, but on the other hand it should be possible to detect that the DC current I L falls below a very small threshold value.
- a very small threshold value can occur, for example, in the supply of power to an electrical system in an aircraft.
- the direct current I L corresponds to the current drawn from an on-board battery, this can, for example, briefly and when the aircraft engines are started suddenly assume a value of approx. 1,000 A. This leads to considerable heating of the current conductor SL and thus of the direct current converter.
- the on-board electrical system feeds itself, in particular by means of generators driven by it. It is advantageous and sometimes necessary to detect this transition moment between battery and self-supply.
- This transition moment can be defined, for example, by the fact that the direct current I L taken from the on-board battery has decreased from originally approx. 1000 A to less than 3 A. Due to the addition of the Hall voltages of the antiparallel Hall generators and the compensation of the temperature profile of the zero point offset voltage, the new DC converter according to the invention is particularly suitable, despite previous strong heating, to map such a low switching threshold of approx. 3 A in the output signal ⁇ U H with relatively high accuracy.
Abstract
Description
Die Neuerung betrifft einen magnetischen Gleichstromwandler zur Erfassung von Gleichströmen in einem Stromleiter mit großem Querschnitt, welcher von einem Gleichstrom mit insbesondere kurzzeitig und storßartig auftretenden hohen Werten durchflossen wird.The innovation relates to a magnetic direct current converter for detecting direct currents in a current conductor with a large cross section, through which a direct current with high values, in particular those that occur briefly and in a burst-like manner, flows.
Bei magnetischen Wandlern ist es insbesondere zur Erhöhung der Meßempfindlichkeit bekannt, d.h. zur Erhöhung der am Ausgang zur Verfügung stehenden, auswertbaren Meßspannung, den Stromleiter des zu erfassenden Stromes nicht nur einmal, sondern in Form von mehreren um einen magnetischen Schenkel ge führten Windungen hindurchzuführen.In magnetic transducers, it is known in particular to increase the sensitivity of measurement, i.e. to increase the available at the output, evaluable measuring voltage, the conductor of the current to be detected not only once, but in the form of several ge around a magnetic leg led turns.
Bei einem Stromleiter mit einem großen Querschnitt, der einen Gleichstrom mit unter Umständen kurzzeitig und stoßartig auftretenden hohen Werten führen kann, ist eine derartige Wicklung um einen Schenkel des Wandlers dagegen in der Regel sehr aufwendig bzw. nicht möglich. Vielfach werden derartige Stromleiter in Form von Schienen geradlinig durch den Wandler hindurchgeführt. Es ist somit praktisch nicht möglich, in der bekannten Weise eine Erhöhung des nutzbaren Signalpegels der Meßspannung am Ausgang des Wandlers zu erreichen.In contrast, in the case of a current conductor with a large cross section, which can carry a direct current with high values which may occur briefly and suddenly, such a winding around one leg of the converter is generally very complex or not possible. Such current conductors in the form of rails are frequently passed straight through the converter. It is therefore practically not possible to achieve an increase in the usable signal level of the measuring voltage at the output of the converter in the known manner.
Aufgrund der hohen Gleichstromtragfähigkeit derartiger Stromleiter muß selbst bei nur kurzzeitig und stoßartig auftretenden hohen Gleichstromwerten mit einer erheblichen Erwärmung des Stromleiters, und damit des zur Erfassung des hindurchließenden Gleichstromes dienenden magnetischen Wandlers gerechnet werden. In manchen Anwendungsfällen wird der magnetische Gleichstromwandler auf bis zu 130° C erwärmt. Gegenüber einem z.B. Umgebungstemperatur von ca. 25° C liegenden, angenomenenDue to the high direct current carrying capacity of such current conductors, considerable heating of the current conductor, and thus the magnetic transducer used to detect the direct current passing through, must be expected, even if the high direct current values occur only briefly and suddenly. In some applications, the magnetic DC converter is heated up to 130 ° C. Compared to an assumed, for example, ambient temperature of approx. 25 ° C
Temperaturnullpunkt führt eine derartige Erwärmung in der Regel aber zu einer erheblichen temperaturdriftabhängigen Verfälschung der nutzbaren Meßspannung am Ausgang des Wandlers. Dabei wirkt sich besonders der Temperaturverlauf der Nullpunktsoffsetspannung aus. Bei den Gleichstromwandlern mit einem insbesondere gradlinig als Stromschiene hindurchgeführten Stromleiter großen Querschnitts besteht dabei das Problem, das die Amplitude der bei einer großen Erwärmung auftretenden Nullpunktsoffsetspannung größer sein kann als der Wert der ein Abbild des jeweils fließenden Gleichstromes darstellenden Meßspannung am Wandlerausgang.However, such a heating generally leads to a significant temperature drift-dependent falsification of the usable measuring voltage at the output of the converter. The temperature profile of the zero point offset voltage has a particular effect here. In the case of direct current converters with a current conductor of large cross section, which is in particular passed straight through as a busbar, there is the problem that the amplitude of the zero-point offset voltage which occurs when there is a great deal of warming can be greater than the value of the measuring voltage at the converter output which represents the respective flowing direct current.
Der Neuerung liegt die Aufgabe zugrunde, einen magnetischen Gleichstromwandler zur Erfassung von Gleichströmen anzugeben, deren unter Umständen vorübergehende und stoßartige Erhöhung auf hohe Werte eine erhebliche Erwärmung des Gleichstromwandlers zur Folge hat.The innovation is based on the object of specifying a magnetic direct current converter for detecting direct currents, the temporary and sudden increase to high values of which may result in considerable heating of the direct current converter.
Die Aufgabe wird gelöst mit dem im Schutzanspruch angegebenen Gleichstromwandler.The object is achieved with the DC converter specified in the protection claim.
Die Neuerung wird anhand der nachfolgend kurz angeführten Figuren näher erläutert. Dabei zeigt:
- FIG 1 eine vorteilhafte Ausführungsform des neuerungsgemäßen Gleichstromwandlers, und
- FIG 2 beispielhaft den Temperaturverlauf der Nullpunktsoff setspannung von zwei Hallgeneratoren.
- 1 shows an advantageous embodiment of the DC converter according to the innovation, and
- 2 shows an example of the temperature profile of the zero point offset voltage of two Hall generators.
Der neuerungsgemäße magnetische Gleichstromwandler besteht gemäß der Darstellung von FIG 1 aus einem magnetischen Kern MK, durch den ein Stromleiter SL mit großem Querschnitt hindurchgeführt ist. Bei dem in der FIG 1 dargestellten Ausführungsbeispiel ist der Stromleiter SL in Form einer geradlinigen und starren, den Gleichstrom IL führenden Stromschiene ausgeführt. Der magnetische Kern MK ist nicht ringförmig geschlossen, son dern verfügt über einen Luftspalt LS. In diesen sind neuerungsgemäß mindestens zwei antiparallel zueinander angeordnete und thermisch leitend mit dem magnetischen Kern MK verbundene Hallgeneratoren HG1, HG2 eingelegt. Beide Hallgeneratoren werden in bekannter Weise von einer nicht dargestellten Versorgungsspannung über ebenfalls nicht dargestellte Anschlußleitungen gespeist.1, the magnetic DC converter according to the invention consists of a magnetic core MK through which a current conductor SL with a large cross section is passed. In the exemplary embodiment shown in FIG. 1, the current conductor SL is designed in the form of a rectilinear and rigid busbar carrying the direct current I L. The magnetic core MK is not closed in a ring, son has an air gap LS. In accordance with the innovation, at least two Hall generators HG1, HG2, which are arranged antiparallel to one another and are connected in a thermally conductive manner to the magnetic core MK, are inserted. Both Hall generators are supplied in a known manner from a supply voltage, not shown, via connecting lines, also not shown.
Gemäß der Darstellung von FIG 1 werden die Hallspannungen UH(HG1), UH(HG2) der beiden Mallgeneratoren einer zum Gleichstromwandler gehörigen Auswerteschaltung AS zugeführt. Diese bildet bevorzugt mittels einer bekannten Differenzverstärkerschaltung die Differenz zwischen den Hallspannungen, und stellt diese als Meßsignal Δ UH am Ausgang des Gleichstromwandlers zur Verfügung. Die beiden Hallgeneratoren HG1, HG2 zeichnen sich dadurch aus, daß deren Nullpunktsoffsetspannungen UN(T)HG1, UN(T)HG2, d.h. die am Ausgang der Generatoren ohne Anliegen eines Magnetfeldes allein aufgrund der Versorgungsspannungen hervorgerufenen Spannungen, einen möglichst identischen Temperaturverlauf aufweisen. Hallgeneratoren, deren Nullpunktsoffsetspannungen aufgrund von üblichen Exemplarstreuungen stark voneinander abweichende Temperaturverläufe aufweisen, sind nicht geeignet gemäß der Neuerung antiparallel im Luftspalt des magnetischen Kernes des Gleichstromwandlers eingesetzt zu werden.1, the Hall voltages U H (HG1), U H (HG2) of the two mall generators are fed to an evaluation circuit AS belonging to the DC converter. This preferably forms the difference between the Hall voltages by means of a known differential amplifier circuit and makes this available as a measurement signal Δ U H at the output of the DC converter. The two Hall generators HG1, HG2 are distinguished by the fact that their zero point offset voltages U N (T) HG1 , U N (T) HG2 , ie the voltages caused at the output of the generators without a magnetic field solely due to the supply voltages, have an identical temperature profile . Hall generators, the zero point offset voltages of which differ greatly from one another due to the usual specimen variations, are not suitable according to the innovation to be used antiparallel in the air gap of the magnetic core of the DC converter.
Der neuerungsgemäße Gleichstromwandler hat den besonderen Vorteil, daß zum einen der Pegel der auswertbaren Differenzhallspannung Δ UH am Ausgang aufgrund der Subtraktion der zwei Vorzeichen unterschiedlichen Hallspannungen UH der antiparallelen Generatoren doppelt so hoch ist als bei Verwendung eines einzigen Hallgenerators. Diese Subtraktion der Hallspannungen von einen möglichst identischen Temperaturverlauf der Nullpunktsoffsetspannungen verfügenden antiparallelen Hallgenratoren hat den weiteren Vorteil, daß sich diese Temperaturverläufe nahezu vollständig kompensieren. Dies wird desweiteren anhand der FIG 2 näher erläutert.The new DC converter according to the invention has the particular advantage that, on the one hand, the level of the evaluable differential Hall voltage Δ U H at the output is twice as high due to the subtraction of the two signed different Hall voltages U H of the antiparallel generators than when using a single Hall generator. This subtraction of the Hall voltages from an antiparallel Hall generator having an identical temperature profile for the zero point offset voltages has the further advantage that these temperature profiles are almost identical fully compensate. This is further explained with reference to FIG 2.
Das Diagramm der FIG 2 zeigt aufgetragen über der bevorzugt in °C angegebenen Temperatur T den Verlauf der in Form von Geraden angenäherten Nullpunktsoffsetspannungen UN(T). Diese entsprechen den Hallspannungen UH (B=0) am Ausgang der Generatoren bei Fehlen eines Magnetfeldes B im Luftspalt LS. Die beiden in der FIG 2 eingetragenen Temperaturverläufe der Nullpunktsoffsetspannungen UN(T)HG1, UN(T)HG2 der beiden antiparallelen Mallgeneratoren weichen neuerungsgemäß nur geringfügig voneinander ab. Sie verfügen somit über Steigungen mit identischen Vorzeichen und annähernd gleichen Werten. In der FIG 2 sind zwei Temperaturbetriebspunkte bei Umgebungstemperatur T0 = 25° und T1 = 100° C beispielhaft eingetragen.Plotted over the temperature T, which is preferably given in ° C., the diagram in FIG. 2 shows the course of the zero point offset voltages U N (T) approximated in the form of straight lines. These correspond to the Hall voltages U H (B = 0) at the output of the generators in the absence of a magnetic field B in the air gap LS. The two temperature profiles of the zero point offset voltages U N (T) HG1 , U N (T) HG2 of the two antiparallel mall generators entered in FIG. 2 differ only slightly from one another in accordance with the innovation. They therefore have gradients with identical signs and approximately the same values. Two temperature operating points at ambient temperature T0 = 25 ° and T1 = 100 ° C are entered as an example in FIG.
So hat beispielsweise in dem als Temperaturnullpunkt angenommene Betriebspunkt T0 = 25° die Nullpunktsoffsetspannung UN(T0)HG2 des Hallgenerators HG2 den relativ großen, zwischen den exemplarstreuungsbedingten Minimal- und Maximalwerten UNMI, UNMA liegenden Wert. Werden dagegen gemäß der Neuerung die Hallspannungen am Ausgang der antiparallelen Generatoren voneinander subtrahiert, so reduziert sich die Nullpunktsoffsetspannung im Wandlerausgangssignal Δ UH auf den nahezu verschwindenden, zwischen den Kurven UN(T)HG1 und UN(T)HG2 im Temperaturnullpunkt T0 liegenden Wert UN(T0)HG2 - HG1.For example, in the operating point T0 = 25 ° assumed as the temperature zero point, the zero point offset voltage U N (T0) HG2 of the Hall generator HG2 has the relatively large value lying between the minimum and maximum values U NMI , U NMA caused by the sample scatter. On the other hand, if, according to the innovation, the Hall voltages at the output of the anti-parallel generators are subtracted from each other, the zero point offset voltage in the converter output signal Δ U H is reduced to the almost vanishing, lying between the curves U N (T) HG1 and U N (T) HG2 at the temperature zero point T0 Value U N (T0) HG2 - HG1 .
Ist die Temperatur des Gleichstromwandlers z.B. auf den Wert T1 = 100° C erhöht, so hat dies im Vergleich zum Temperaturnullpunkt bei T0 = 25° eine Erhöhung der Nullpunktsoffsetspannung UN(T)HG2 z.B. des zweiten Hallgenerators um den Wert Δ UN(T1) HG2 zur Folge. Beim neuerungsgemäßen Gleichstromwandler tritt dagegen im Arbeitspunkt T1 = 100° C lediglich ein dem Abstand zwischen den Temperaturverläufen UN(T)HG1 und UN(T)HG2 entsprechender, erheblich kleinerer absoluter Wert der Nullpunktsoffsetspannung UN(T1)HG2 - HG1 auf.If, for example, the temperature of the DC converter is increased to the value T1 = 100 ° C, this has an increase in the zero point offset voltage U N (T) HG2, for example of the second Hall generator, by the value Δ U N (T1) in comparison to the temperature zero point at T0 = 25 ° ) Result in HG2 . In contrast, with the new DC converter according to the invention , only a significantly smaller absolute value of the zero point offset voltage U N (T1) HG2- HG1 corresponding to the distance between the temperature profiles U N (T) HG1 and U N (T) HG2 occurs at the operating point T1 = 100 ° C.
Gemäß einer weiteren Ausführungsform ist es vorteilhaft, bevorzugt im Temperaturnullpunkt T0 = 25° C die Nullpunktsoffsetspannung UN(T0)HG2 - HG1 bevorzugt durch Parallelverschiebung einer der beiden Temperaturverläufe UN(T)HG1 bzw. UN(T)HG2 nahezu vollständig zu beseitigen. Eine derartige Verschiebung ist durch schaltungstechnische Maßnahmen in der Auswerteschaltung AS auf bekannte Weise möglich. In der FIG 2 ist am Beispiel von U
In einer weiteren Ausführungsform ist es auch möglich, vier Hallgeneratoren im Luftspalt anzuordnen. Dabei sind jeweils zwei Generatoren paarweise parallel zueinander angeordnet, während die Generatorpaare antiparallel zueinander angeordnet sind. Die Hallspannungen der Generatoren eines jeden Paares werden dabei addiert und die sich so ergebenden Summen substrahiert.In a further embodiment, it is also possible to arrange four Hall generators in the air gap. Two generators are arranged in pairs parallel to each other, while the generator pairs are arranged anti-parallel to each other. The Hall voltages of the generators of each pair are added and the resulting sums are subtracted.
Der neuerungsgemäße Gleichstromwandler kann besonders vorteilhaft dann verwendet werden, wenn der Gleichstrom IL durch den Stromleiter SL zum einen unter Umständen kurzzeitig und stoßartig sehr hohe Werte annehmen kann, zum anderen aber das Unterschreiten eines recht kleinen Schwellwertes durch den Gleichstrom IL detektierbar sein soll. Ein derartiger Fall kann z.B. bei der Stromversorgung eines Bordnetzes in einem Flugzeug auftreten. Entspricht in einem solchen Fall der Gleichstrom IL dem aus einer Bordbatterie gezogenen Strom, so kann dieser z.B. beim Anlassen der Flugzeugtriebwerke kurzzeitig und stoßartig einen Wert von ca. 1 000 A annehmen. Dies führt zu einer erheblichen Erwärmung des Stromleiters SL und somit des Gleichstromwandlers. Nach erfolgreichem Start der Triebwerke speist sich das Bordnetz insbesondere mittels davon angetriebener Generatoren im Eigenbetrieb selbst. Es ist vorteilhaft und manchmal notwendig, diesen Übergangsmoment zwischen Batterie- und Eigenspeisung zu detektieren. Dieser Übergangsmoment kann beispielsweise dadurch definiert sein, daß der aus der Bordbatterie entnommene Gleichstrom IL von ursprünglich ca. 1 000 A auf weniger als 3 A zurückgegangen ist. Der neuerungsgemäße Gleichstromwandler ist aufgrund der Addition der Hallspannungen der antiparallelen Hallgeneratoren und der Kompensation des Temperaturverlaufes der Nullpunktsoffsetspannung besonders geeignet, trotz vorangegangener starker Erhitzung eine derart niedrige Schaltschwelle von ca. 3 A im Ausgangssignal Δ UH mit relativ hoher Genauigkeit abzubilden.The new DC converter according to the invention can be used particularly advantageously when the DC current I L through the current conductor SL can on the one hand take on very high values for a short time and suddenly, but on the other hand it should be possible to detect that the DC current I L falls below a very small threshold value. Such a case can occur, for example, in the supply of power to an electrical system in an aircraft. In such a case, if the direct current I L corresponds to the current drawn from an on-board battery, this can, for example, briefly and when the aircraft engines are started suddenly assume a value of approx. 1,000 A. This leads to considerable heating of the current conductor SL and thus of the direct current converter. After the engines have started successfully, the on-board electrical system feeds itself, in particular by means of generators driven by it. It is advantageous and sometimes necessary to detect this transition moment between battery and self-supply. This transition moment can be defined, for example, by the fact that the direct current I L taken from the on-board battery has decreased from originally approx. 1000 A to less than 3 A. Due to the addition of the Hall voltages of the antiparallel Hall generators and the compensation of the temperature profile of the zero point offset voltage, the new DC converter according to the invention is particularly suitable, despite previous strong heating, to map such a low switching threshold of approx. 3 A in the output signal Δ U H with relatively high accuracy.
Claims (1)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE8902904U | 1989-03-09 | ||
| DE8902904U DE8902904U1 (en) | 1989-03-09 | 1989-03-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0386319A2 true EP0386319A2 (en) | 1990-09-12 |
| EP0386319A3 EP0386319A3 (en) | 1991-07-24 |
Family
ID=6836914
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19890119759 Withdrawn EP0386319A3 (en) | 1989-03-09 | 1989-10-24 | Magnetic dc to dc converter with reduced temperature drift |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0386319A3 (en) |
| DE (1) | DE8902904U1 (en) |
| DK (1) | DK58190A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2692991A1 (en) * | 1992-06-26 | 1993-12-31 | Renault | Magnetic compensation current detector for measuring electric vehicle battery current - uses amplifiers connected to secondary magnetic circuit to compensate for primary magnetic field. |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6028216A (en) * | 1983-07-26 | 1985-02-13 | Midori Anzen Kk | Dc current detecting current transformer |
| DE3347315C1 (en) * | 1982-12-18 | 1985-02-14 | Maag-Zahnräder & -Maschinen AG, Zürich | Tooth measuring probe |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1935585U (en) * | 1963-09-26 | 1966-03-31 | Siemens Ag | CURRENT CONVERTER WITH HALL GENERATORS. |
| BE756784A (en) * | 1970-09-29 | 1971-03-01 | Buyse Herve | MAGNETIC COMPENSATION CURRENT TRANSFORMER, |
| JP3020340B2 (en) * | 1992-03-10 | 2000-03-15 | 日本放送協会 | Optical waveguide type optical device |
-
1989
- 1989-03-09 DE DE8902904U patent/DE8902904U1/de not_active Expired
- 1989-10-24 EP EP19890119759 patent/EP0386319A3/en not_active Withdrawn
-
1990
- 1990-03-06 DK DK58190A patent/DK58190A/en not_active Application Discontinuation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3347315C1 (en) * | 1982-12-18 | 1985-02-14 | Maag-Zahnräder & -Maschinen AG, Zürich | Tooth measuring probe |
| JPS6028216A (en) * | 1983-07-26 | 1985-02-13 | Midori Anzen Kk | Dc current detecting current transformer |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN, Band 9, Nr. 147 (E-323)[1870], 21. Juni 1985; & JP-A-60 28 216 (MIDORI) 13-02-1985 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2692991A1 (en) * | 1992-06-26 | 1993-12-31 | Renault | Magnetic compensation current detector for measuring electric vehicle battery current - uses amplifiers connected to secondary magnetic circuit to compensate for primary magnetic field. |
Also Published As
| Publication number | Publication date |
|---|---|
| DK58190D0 (en) | 1990-03-06 |
| EP0386319A3 (en) | 1991-07-24 |
| DK58190A (en) | 1990-09-10 |
| DE8902904U1 (en) | 1989-05-03 |
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