CA1101071A - Device for converting intensity of magnetic or electromagnetic field into electric signal - Google Patents
Device for converting intensity of magnetic or electromagnetic field into electric signalInfo
- Publication number
- CA1101071A CA1101071A CA300,619A CA300619A CA1101071A CA 1101071 A CA1101071 A CA 1101071A CA 300619 A CA300619 A CA 300619A CA 1101071 A CA1101071 A CA 1101071A
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- Canada
- Prior art keywords
- ferromagnetic plates
- resistance strain
- strain gauge
- resistance
- ferromagnetic
- 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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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16504—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed
- G01R19/16509—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed using electromagnetic relays, e.g. reed relay
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
DEVICE FOR CONVERTING INTENSITY OF MAGNETIC
OR ELECTROMAGNETIC FIELD INTO ELECTRIC SIGNAL
ABSTRACT OF THE DISCLOSURE
A device for converting the intensity of a magnetic or an electromagnetic field into an electric signal wherein movable elements are made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other. Mounted on the deformation section in the immediate vicinity to the place where the ferromagnetic plate is fixed in its support is an element sensing the displacements of the free ends of the plates with respect to each other. The sensing element is made as at least one resistance strain gauge connected to a measuring circuit.
OR ELECTROMAGNETIC FIELD INTO ELECTRIC SIGNAL
ABSTRACT OF THE DISCLOSURE
A device for converting the intensity of a magnetic or an electromagnetic field into an electric signal wherein movable elements are made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other. Mounted on the deformation section in the immediate vicinity to the place where the ferromagnetic plate is fixed in its support is an element sensing the displacements of the free ends of the plates with respect to each other. The sensing element is made as at least one resistance strain gauge connected to a measuring circuit.
Description
DEVICE FOR CONVERTING ~GNETIC OR ELECTROMAGNETIC FIEL~ TEN-SIT~' INl'O ELECTRIC SIGNAL
App]ication of the Invention Tile present invention relates to electromecllanic tran-sducer devices and in particular to devices for converting a magnetic field intensity into an electric signal designed around magnetically controlled contacts.
Background of the Invention ~ nown in the art are magnetically controlled contacts made as ferromagnetic plates rigidly fixed in a support and over-lapping each other at their free ends which will come cioser to one another when the current flowing through a magnetizing coil grows from zero to a certain value and diverge when it continues growing. (see, for instance, US Patent No 3551860, Cl. 335-151, published in 1969).
A variation of the magnetic field intensity will result in a change of the gap between the ferromagnetic plates and, con-sequently, of the intercontact capacitance. The teclmique based on the use of the intercontact capacitance of the ferromagnetic plates as a parameter specifying the magnitude of a magnetic field intensity suffers from a number of drawbacks caused by the fact that with shifts of the plates the intercontact capacitance will vary in a non-linear way and at a low multiplicity factor.
Besides, the absolute values of this capacitance are quite small (from 0.5 to 3.0 pF) and therefore their measurement re~uires that high fre~iuencies should be used.
One of the known designs that is the closest to the one proposed herein relates to a device for converting a magnetic field intensity into an electric signal which comprises movable elements made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other and an element for sensing the relative displacement of the free ends of the g ferromagnetic platcs, the element being connected to a measuring circuit. The displacement of the free ends of the ferromagnetic plates is measured with the use of photodetector elements, such as a photomultiplierand an illumination ]apm, mounted at opposite sides of the gap between the overlapping ends of the ferromagnetic plates. In such devices the magnetic field intensit~ is converted into a current flowing through a photodetector element. ~see, for instance, Zaretskas V.-S.S., Ragulskene V.L. "Mercury commuta-tor elements for automatic devices". Energia, 1971, p. 51).
However, the use of such devices as a means for conver-ting the intensity of a magnetic field into an electric value requires a stable power supply, a dustless environment and precise adjustment of the ferromagnetic plates Wit}l respect to the illu-minator-photodetec~or axis. Negligence to these requirements tends to reduce the reliability of such converters. sesides, their conversion range is limited when the size of ferromagnetic plates is increased.
srief Description of the Invention The object of the present invention is to provide a device for converting the intensity of a magnetic field into an eiectric signal which would have high reliability and a wide conversion range.
The essence of this invention consists in providing a device for converting the intensit~ of a magnetic or electro-magnetic field into an electric signal comprising movable elements made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other, and an element sensing the respective displacement of the free ends of the ferromagnetic plates which is connected to a measuring circuit wherein, according to the invention, the sensitive element is made as at least one resistance strain gauge mounted at the deformation section in the immediate vicinity to the point where the ferromagnetic plate is .,.~, ~, .
17~
fixed in the support.
Conveniently the magnetic field source is made as a current conduit while the device is provided with an assembly for rotating the axis of the resistance strain gauge with respect to the longitudinal axis of the current conduit, the assembly being rigidly coupled with the supports.
Conveniently also the device is provided wlth a permanent magnet mounted so that it can be shifted with respect to the ferromagnetic plates in order to vary the resistance rating of the strain gauge the value of which is used as an additional indication of the permanent magnet position.
Preferably, the device should comprise a control mag-netizing coil connected, via an amplifier-converter, to an a-c voltage source of or periodic variations in the strain gauge resistance.
Brief Description of the Drawings The invention will be better understood from the following description of its embodiments given by way of example and shown in the accompanying drawings in which:
Fig. 1 presents a device for converting the intensity of a magnetic field into an electric signal, the device being pro-vided with one resistance strain gauge, according to the invention;
Fig. 2 presents the device as shown in Fig. 1, viewed from above, according to the invention;
Fig. 3 presents a version of the proposed converter ~evice with two resistance strain gauges according to the inventlon;
Fig. 4 presents the proposed converter device with four resistance strain gauges according to the invention;
Fig. 5 presents a version of the proposed converter device with four resistance strain gauges installed on membranes which are secured to the body of the device (longitudinal cross section of the body and the membranes) according to the invention;
Fig. 6 presents a version of the proposed converter device Witil a field source made as a current conduit (partial longitudinal cross section) according to the invention;
Fig. 7 presents a version of the proposed converter device wherein the field source is made as a permanent magnet according to the invention;
Fig. 8 presents a diagram of connections between re-sistance strain gauges and the measuring circuit in the proposed converter device according to the invention;
Fig. 9 presents a version of the proposed converter device wherein the resistance strain gauges are connected, via an amplifier-converter, to a magnetizing control coil.
Detailed description of the Invention The proposed device for converting the intensity of a magnetic field into an electric signal comprises movable elements made as ferromagnetic plates 1 (Fig. 1) and 2 rigidly fixed in supports 3 and 4 so that their free ends overlap each other. The device comprises also an element sensing the relative displacement of the free ends of the ferromagnetic plates represented as at least one resistance strain gau~e mounted at the deformation section in the immediate vicinity to the point where the ferro-magnetic plate is fixed in the support. The embodiment of the inventlon described herein uses one resistance strain gauge 5 mounted on the ferromagnetic plate 1.
Terminals 6,7 of the resistance strain gauge 5 are connected to a measuring circuit 8 (Fig. 2).
Fig. 3 presents another version of the embodiment of the device for converting the intensity of a magnetic field into an electric signal which, according to the invention, comprises an additional resistance strain gauge 9 having terminals 10 and 11 mounted in a way similar to that of the resistance strain gauge in the immediate vicinity to the point where the f~rromagnetic ,.. .
7~
plate 1 is fixed in the support 3 but on the opposite surface of plate 1.
An additional resistance strain gauge 9 subjected to deformation opposite to that of the resistance strain gauge 5 and located in the immediate vicinity to it makes it possible to raise the magnitude of the useful signal (in the form of resistance increment) and to reduce the temperature-dependent conversion error caused by resistance temperature variations of the strain gauge.
Fig. 4 presents another version of the embodiment of the device for converting the intensity of a magnetic field into an electric signal which, according to the invention, comprises, in addition to those in the version of Fig. 3, still two more resistance strain gauges 12 and 13 having terminals 14, 15, 16, 17 mounted on the ferromagnetic plate 2.
The use of the two more resistance strain gauges 12 and 13 makes it possible to raise the magnitude of the useful signal still further though the displacement of the ferromagnetic plates 1 and 2 is the same.
The device for converting the intensity of a magnetic field into an electric signal proposed herein and shown in Fig. 5 differs from the version presented in Fig. 4 in that it comprises a casing 18 housin~ the ferromagnetic plates 1 and 2. The casing 18 is made of non-~erromagnetic material. The butt endsof the caslr.g 18 are provided with broad sections carrying membranes 19 and 20 secured to them. The diameter of these membranes 19, 20 exceeds to a certain extent that of the casing 18 in its central section. The membranes 19 and 20 have their edges rigidly fixed (welded) to the casing 18. Connected rigidly to said membranes 19 and 20 at their centers are the ferromagnetic plates 1 and 2 respectively. The connection may be either sealed or unsealed.
In the version of the embodiment described herein the membranes 19 5J~ - 6 -~o~o~
and 20 serve as resilient elements and perform the function of supports for the ferromagnetic plates 1 and 2. Placed at the outer surfaces of the membranes 19 and 20 are the resistance strain gauges 5, 9 and 12, 13 respectively, which are secured to deformation sections in the immediate vicinity to the points where the ferromagnetic plates 1 and 2 are fixed.
The use of the casing 18 and the m~mbranes 19 and 20 which are connected rigidly to it makes it possible, firstly to place the resistance strain gauges 5, 9, 12, 13 after the major cornponents, including the ferromagnetic plates 1 and 2 have been assembled; secondly, to arrange tne resistance strain gauges 5, 9, 12, 13 at the outer surfaces of the membranes 19, 20 r which facilitates the connection of other components to the terminals of the resistance strain gauges 5, 9, 12, 13, and thirdly, to increase the number of resistance strain gauges in the s~stem by means of securing them at the deformation sections of the mem-branes 19, 20 Still another advantage of the version of the embodiment of the proposed invention described herein consists in that its design features allow to automate the procedure of its production.
Fig. 6 pr~sents another version of the device according to the invention wherein the field source is made as a current conduit 2I. In addition the device is provided with an assembly 22 for rotating the axis of the resistance strain gauge 5 about the longitudinal axis of the current conduit 21. The assembly 22 is rigidly coupled with the supports 3 and 4 through the casing 18. The supports 3 and 4 are made mainly of an isolation material as washers. The casing 18 is made of non-ferromagnetic materials.
In order to increase the accuracy of converting the intensity of a magnetic field into an electric signal the casing 18 is preferably made of copper so as to form a short-circuited winding.
The use of the rotation assembly 22 allows to vary the range and the sensitivity of converting the intensity of a magnetic field generated by the current conduit 21 into an electric signal.
Fig. 7 presents a version of the device according to the invention wherein the field source is made as a permanent magnet 23 which serves as a complementary element of the proposed device. Simultaneously the permanent magnet 23 performs the function of a means for transferring the data on its position, to which end it is mounted so that it can be shifted with respect to the ferromagnetic plates 1 and 2 and hence, vary the resistance of tlle strain gauge 5. The permanent magnet 5 is shifted with the help of a holder 24 wherein the permanent magnet 23 is fixed and by means of a rod 25 housed in guides 26 and rigidly coupled with the holder.
The directions of the permanent magnet 23 shifts with respect to the longitudinal axes of the Eerromagnetic plates 1, 2 as indicated by arrows in Fig. 7 are not the only possible.
The present version of the proposed device allows to consider the shift and the position of the permanent magnet 23 in case of its rotation as well as in case of its movement along the ferromagnetic plates 1 and 2.
An index "X" indicates the effect caused by a sensor o~
the parameter to be measured (not shown in Fig. 7) on the rod 25 which shifts the permanent magnet 23. The functions of the sensor of the parameter to be measured could be performed by a pressure pic~-up, a temperature sensor, etc. which converts the parameter to be measured into a displacement. The assembly described above is especially suitable in transferring the results of measurements to a remote user.
One of the possible embodiments of the converter version hereinbefore described is a device for converting angular position ~- of the rod 25 of the permanent magnet 23 into variations of the resistance of the strain gauge 25. Such a converter is used most 7:L
preferably in cases when the rotation rates of the rod 25 are about zero. The above circumstance is due to the fact that the proposed device for converting the intensity of a magnetic field into an electric signal wherein ~he functions of a field source are per-formed by the permanent magnet 23 combines in a most advantageous way both a means allowing to determine the amount of displacement of the permanent magnet and a means presenting the information on the position (coordinate) of the permanent magnet 23. In par-ticular the proposed design makes it possible to reliably and accurately solve the problem of determining the position of slowly rotating rotors in electric machines such as step-by-step motors.
Fig. 8 presents a version of the device according to the invention wherein the resistance strain gauges 5, 9, 12 and 13 are interconnected to one another and to the measuring circuit.
Shown in Fig. 8 in particular is the interconnection of said resistance strain gauges 5, 9, 12, 13 into a bridge circuit one diago~al of which is connected to a source of the supply voltage U and the other, to the measuring circuit 8. The above method of interconnecting the resistance strain gauges 5, 9, 12, 13 and the measuring circuit 8 makes it possible to obtain a large electric signal in the form of an output current. This is due to the fact that a variation of the magnetic field intensity will cause a change of the resistance in all the four strain gauges 5, 9, 12, 13. Besides, the error introduced by ambient temperature variations could be reduced drastically by means of selecting resistance strain gauges having similar temperature responses.
The above device employing the proposed interconnection circuit could be used to advantage as a remotely variable resistor, the rating of which being varied either by means of changing the current thatflows through the control magnetizing coil or by means of shifting the p~rl,lanent magnet. An additional advantage of the ,, _ g _ . .:. ~.
7~
proposed method of interconnecting the resistance strain gauges consists in that it allows to obtain an output in the form of a current signal proportional to the product of the supply voltage "U" by the current "I" which determines the intensity of the mag-netic field being converted by the proposed device into an electric signal. In case the supply voltage "U" is set equal to a voltage drop across the ohmic-inductance load having the current "I"
flowing through it the output of the circuit will be proportional to the power consumed by the load.
lG Fig. 9 presents a version of the device for converting the intensity of a magnetic field into an electric signal accord-ing to the invention which comprises a control magnetizing coil 27 connected, via an amplifier-converter 28, to the resistance strain gauges 5, 9, 12, 13. This design of the proposed deviee makes it possible to obtain a feedback loop using the position of the ferromagnetic plates 1 and 2 as the source of a feedback signal which can be either positive or negative, which allows to vary the characteristics of convert:ing the intensity of a mag-netie field into an eleetrie signal. In particular the deviee ean operate as a null-indicator. However, in this case it is re~uired that the electromagnetic field generated by the control magnetizing coil 27 should compensate for the effect of the ex-ternal magnetic field to be eonverted into an eleetric signal.
If there are several control magnetizing coils (not shown in Fig.
9) the displacement of the ferromagnetic plates 1 and 2 and their resultant position will be determined by the sum (or difference) effect of the coils.
In another version of the embodiment of Fig.-9, the control magnetizing coil 27 is connected, via the amplifier-con-verter 28, to an a-c voltage source, thereby providing for periodie variations in the resistance of the strain gauges 5, 9, 12, 13 and enabling a-c amplifiers to be used for hand~ing signals from the - 10 - `
7~
strain gauges.
The device for converting the intensity of a magnetic or an electromagnetic field into an electrlc signal shown in Figs. 1 and 2 operates as follows.
As soon as a control signal in the form of a longitudinal or a transverse magnetic or electromagnetic field is applied to - a system of ferromagnetic plates 1 and 2 the latter will start approaching each other and with the further increase of the control signal they will diverge, provided that the initial gap and the amount of overlapping between the ferromagnetic plates 1 and 2 exceed certain limiting values, i.e. the values at which the ferromagnetic plates 1 and 2 still contact each other. In case the above requirements are not met the proposed device will operate within the time interval from the moment the ferromagnetic plates 1 and 2 start approaching each other till the moment when they start moving with a jump to contact each other. In any case, however, the above mutual approach of the ferromagnetic plates 1 and 2 is accompanied by their resilient bending strain since ~; they are rigidly fixed in the supports 3 and 4. The outer sur-faces of the ferromagnetic plates 1 and 2 expand while the inner ones contract. In the particular case of cantilever arrangement of the ferromagnetic plates 1 and 2 the deformation section sub-jected to the maximum strain will ~e located in the immediate vicinity to the point where the ferromagnetic plate is fixed in the support 3. It is at this section that the resistance strain gauge should be located. A properly selected and mounted re-sistance strain guage will vary its resistance in proportion to the displacement of the free end of the ferromagnetic plate 1.
The variations of the resistance of the strain gauge 5 are sensed by the measuring circuit 8 so that its output indicates the intensity of the magnetic or electromagnetic field.
The operation of the version of the proposed device as 7~
shown in Fig. 3 is similar to that of the version presented in Figs. l and 2. However, the use of complementary resistance strain guage 9 makes it possible to compensate for temperature errors and to raise the level of the useful signal in any of the known ways.
The operation of the device for converting the intensi-ty of a magnetic or electromagnetic field into an electric signal arranged as shown in Fig. 4 is similar to that of the previous version of the device. In order to raise the level of the output still higher and to reduce the error to the minimum it is neces-sary to select the resistance strain gauges 5, 9, 12 and 13 so that they have similar responses and to install the ferromagnetic plates 1 and 2 symmetrically so as their free ends bend to one and the same extent while the resistances of the strain gauges 5, 13 and 9, 12 are equal.
The operation of the device arranged as shown in Fig. 5 is basically the same as that of the previous version. The fact that the inside of the device is protected with a casing allows to stabilize its response to a certain extent against variations of the amount of dust, gas and other ingredients of the environ-ment. The major difference, however, consists in-the use of the deformation suffered by the membranes l9 and 20 performing the functions of resilient elements. The ferromagnetic plates l and
App]ication of the Invention Tile present invention relates to electromecllanic tran-sducer devices and in particular to devices for converting a magnetic field intensity into an electric signal designed around magnetically controlled contacts.
Background of the Invention ~ nown in the art are magnetically controlled contacts made as ferromagnetic plates rigidly fixed in a support and over-lapping each other at their free ends which will come cioser to one another when the current flowing through a magnetizing coil grows from zero to a certain value and diverge when it continues growing. (see, for instance, US Patent No 3551860, Cl. 335-151, published in 1969).
A variation of the magnetic field intensity will result in a change of the gap between the ferromagnetic plates and, con-sequently, of the intercontact capacitance. The teclmique based on the use of the intercontact capacitance of the ferromagnetic plates as a parameter specifying the magnitude of a magnetic field intensity suffers from a number of drawbacks caused by the fact that with shifts of the plates the intercontact capacitance will vary in a non-linear way and at a low multiplicity factor.
Besides, the absolute values of this capacitance are quite small (from 0.5 to 3.0 pF) and therefore their measurement re~uires that high fre~iuencies should be used.
One of the known designs that is the closest to the one proposed herein relates to a device for converting a magnetic field intensity into an electric signal which comprises movable elements made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other and an element for sensing the relative displacement of the free ends of the g ferromagnetic platcs, the element being connected to a measuring circuit. The displacement of the free ends of the ferromagnetic plates is measured with the use of photodetector elements, such as a photomultiplierand an illumination ]apm, mounted at opposite sides of the gap between the overlapping ends of the ferromagnetic plates. In such devices the magnetic field intensit~ is converted into a current flowing through a photodetector element. ~see, for instance, Zaretskas V.-S.S., Ragulskene V.L. "Mercury commuta-tor elements for automatic devices". Energia, 1971, p. 51).
However, the use of such devices as a means for conver-ting the intensity of a magnetic field into an electric value requires a stable power supply, a dustless environment and precise adjustment of the ferromagnetic plates Wit}l respect to the illu-minator-photodetec~or axis. Negligence to these requirements tends to reduce the reliability of such converters. sesides, their conversion range is limited when the size of ferromagnetic plates is increased.
srief Description of the Invention The object of the present invention is to provide a device for converting the intensity of a magnetic field into an eiectric signal which would have high reliability and a wide conversion range.
The essence of this invention consists in providing a device for converting the intensit~ of a magnetic or electro-magnetic field into an electric signal comprising movable elements made as ferromagnetic plates rigidly fixed in supports so that their free ends overlap each other, and an element sensing the respective displacement of the free ends of the ferromagnetic plates which is connected to a measuring circuit wherein, according to the invention, the sensitive element is made as at least one resistance strain gauge mounted at the deformation section in the immediate vicinity to the point where the ferromagnetic plate is .,.~, ~, .
17~
fixed in the support.
Conveniently the magnetic field source is made as a current conduit while the device is provided with an assembly for rotating the axis of the resistance strain gauge with respect to the longitudinal axis of the current conduit, the assembly being rigidly coupled with the supports.
Conveniently also the device is provided wlth a permanent magnet mounted so that it can be shifted with respect to the ferromagnetic plates in order to vary the resistance rating of the strain gauge the value of which is used as an additional indication of the permanent magnet position.
Preferably, the device should comprise a control mag-netizing coil connected, via an amplifier-converter, to an a-c voltage source of or periodic variations in the strain gauge resistance.
Brief Description of the Drawings The invention will be better understood from the following description of its embodiments given by way of example and shown in the accompanying drawings in which:
Fig. 1 presents a device for converting the intensity of a magnetic field into an electric signal, the device being pro-vided with one resistance strain gauge, according to the invention;
Fig. 2 presents the device as shown in Fig. 1, viewed from above, according to the invention;
Fig. 3 presents a version of the proposed converter ~evice with two resistance strain gauges according to the inventlon;
Fig. 4 presents the proposed converter device with four resistance strain gauges according to the invention;
Fig. 5 presents a version of the proposed converter device with four resistance strain gauges installed on membranes which are secured to the body of the device (longitudinal cross section of the body and the membranes) according to the invention;
Fig. 6 presents a version of the proposed converter device Witil a field source made as a current conduit (partial longitudinal cross section) according to the invention;
Fig. 7 presents a version of the proposed converter device wherein the field source is made as a permanent magnet according to the invention;
Fig. 8 presents a diagram of connections between re-sistance strain gauges and the measuring circuit in the proposed converter device according to the invention;
Fig. 9 presents a version of the proposed converter device wherein the resistance strain gauges are connected, via an amplifier-converter, to a magnetizing control coil.
Detailed description of the Invention The proposed device for converting the intensity of a magnetic field into an electric signal comprises movable elements made as ferromagnetic plates 1 (Fig. 1) and 2 rigidly fixed in supports 3 and 4 so that their free ends overlap each other. The device comprises also an element sensing the relative displacement of the free ends of the ferromagnetic plates represented as at least one resistance strain gau~e mounted at the deformation section in the immediate vicinity to the point where the ferro-magnetic plate is fixed in the support. The embodiment of the inventlon described herein uses one resistance strain gauge 5 mounted on the ferromagnetic plate 1.
Terminals 6,7 of the resistance strain gauge 5 are connected to a measuring circuit 8 (Fig. 2).
Fig. 3 presents another version of the embodiment of the device for converting the intensity of a magnetic field into an electric signal which, according to the invention, comprises an additional resistance strain gauge 9 having terminals 10 and 11 mounted in a way similar to that of the resistance strain gauge in the immediate vicinity to the point where the f~rromagnetic ,.. .
7~
plate 1 is fixed in the support 3 but on the opposite surface of plate 1.
An additional resistance strain gauge 9 subjected to deformation opposite to that of the resistance strain gauge 5 and located in the immediate vicinity to it makes it possible to raise the magnitude of the useful signal (in the form of resistance increment) and to reduce the temperature-dependent conversion error caused by resistance temperature variations of the strain gauge.
Fig. 4 presents another version of the embodiment of the device for converting the intensity of a magnetic field into an electric signal which, according to the invention, comprises, in addition to those in the version of Fig. 3, still two more resistance strain gauges 12 and 13 having terminals 14, 15, 16, 17 mounted on the ferromagnetic plate 2.
The use of the two more resistance strain gauges 12 and 13 makes it possible to raise the magnitude of the useful signal still further though the displacement of the ferromagnetic plates 1 and 2 is the same.
The device for converting the intensity of a magnetic field into an electric signal proposed herein and shown in Fig. 5 differs from the version presented in Fig. 4 in that it comprises a casing 18 housin~ the ferromagnetic plates 1 and 2. The casing 18 is made of non-~erromagnetic material. The butt endsof the caslr.g 18 are provided with broad sections carrying membranes 19 and 20 secured to them. The diameter of these membranes 19, 20 exceeds to a certain extent that of the casing 18 in its central section. The membranes 19 and 20 have their edges rigidly fixed (welded) to the casing 18. Connected rigidly to said membranes 19 and 20 at their centers are the ferromagnetic plates 1 and 2 respectively. The connection may be either sealed or unsealed.
In the version of the embodiment described herein the membranes 19 5J~ - 6 -~o~o~
and 20 serve as resilient elements and perform the function of supports for the ferromagnetic plates 1 and 2. Placed at the outer surfaces of the membranes 19 and 20 are the resistance strain gauges 5, 9 and 12, 13 respectively, which are secured to deformation sections in the immediate vicinity to the points where the ferromagnetic plates 1 and 2 are fixed.
The use of the casing 18 and the m~mbranes 19 and 20 which are connected rigidly to it makes it possible, firstly to place the resistance strain gauges 5, 9, 12, 13 after the major cornponents, including the ferromagnetic plates 1 and 2 have been assembled; secondly, to arrange tne resistance strain gauges 5, 9, 12, 13 at the outer surfaces of the membranes 19, 20 r which facilitates the connection of other components to the terminals of the resistance strain gauges 5, 9, 12, 13, and thirdly, to increase the number of resistance strain gauges in the s~stem by means of securing them at the deformation sections of the mem-branes 19, 20 Still another advantage of the version of the embodiment of the proposed invention described herein consists in that its design features allow to automate the procedure of its production.
Fig. 6 pr~sents another version of the device according to the invention wherein the field source is made as a current conduit 2I. In addition the device is provided with an assembly 22 for rotating the axis of the resistance strain gauge 5 about the longitudinal axis of the current conduit 21. The assembly 22 is rigidly coupled with the supports 3 and 4 through the casing 18. The supports 3 and 4 are made mainly of an isolation material as washers. The casing 18 is made of non-ferromagnetic materials.
In order to increase the accuracy of converting the intensity of a magnetic field into an electric signal the casing 18 is preferably made of copper so as to form a short-circuited winding.
The use of the rotation assembly 22 allows to vary the range and the sensitivity of converting the intensity of a magnetic field generated by the current conduit 21 into an electric signal.
Fig. 7 presents a version of the device according to the invention wherein the field source is made as a permanent magnet 23 which serves as a complementary element of the proposed device. Simultaneously the permanent magnet 23 performs the function of a means for transferring the data on its position, to which end it is mounted so that it can be shifted with respect to the ferromagnetic plates 1 and 2 and hence, vary the resistance of tlle strain gauge 5. The permanent magnet 5 is shifted with the help of a holder 24 wherein the permanent magnet 23 is fixed and by means of a rod 25 housed in guides 26 and rigidly coupled with the holder.
The directions of the permanent magnet 23 shifts with respect to the longitudinal axes of the Eerromagnetic plates 1, 2 as indicated by arrows in Fig. 7 are not the only possible.
The present version of the proposed device allows to consider the shift and the position of the permanent magnet 23 in case of its rotation as well as in case of its movement along the ferromagnetic plates 1 and 2.
An index "X" indicates the effect caused by a sensor o~
the parameter to be measured (not shown in Fig. 7) on the rod 25 which shifts the permanent magnet 23. The functions of the sensor of the parameter to be measured could be performed by a pressure pic~-up, a temperature sensor, etc. which converts the parameter to be measured into a displacement. The assembly described above is especially suitable in transferring the results of measurements to a remote user.
One of the possible embodiments of the converter version hereinbefore described is a device for converting angular position ~- of the rod 25 of the permanent magnet 23 into variations of the resistance of the strain gauge 25. Such a converter is used most 7:L
preferably in cases when the rotation rates of the rod 25 are about zero. The above circumstance is due to the fact that the proposed device for converting the intensity of a magnetic field into an electric signal wherein ~he functions of a field source are per-formed by the permanent magnet 23 combines in a most advantageous way both a means allowing to determine the amount of displacement of the permanent magnet and a means presenting the information on the position (coordinate) of the permanent magnet 23. In par-ticular the proposed design makes it possible to reliably and accurately solve the problem of determining the position of slowly rotating rotors in electric machines such as step-by-step motors.
Fig. 8 presents a version of the device according to the invention wherein the resistance strain gauges 5, 9, 12 and 13 are interconnected to one another and to the measuring circuit.
Shown in Fig. 8 in particular is the interconnection of said resistance strain gauges 5, 9, 12, 13 into a bridge circuit one diago~al of which is connected to a source of the supply voltage U and the other, to the measuring circuit 8. The above method of interconnecting the resistance strain gauges 5, 9, 12, 13 and the measuring circuit 8 makes it possible to obtain a large electric signal in the form of an output current. This is due to the fact that a variation of the magnetic field intensity will cause a change of the resistance in all the four strain gauges 5, 9, 12, 13. Besides, the error introduced by ambient temperature variations could be reduced drastically by means of selecting resistance strain gauges having similar temperature responses.
The above device employing the proposed interconnection circuit could be used to advantage as a remotely variable resistor, the rating of which being varied either by means of changing the current thatflows through the control magnetizing coil or by means of shifting the p~rl,lanent magnet. An additional advantage of the ,, _ g _ . .:. ~.
7~
proposed method of interconnecting the resistance strain gauges consists in that it allows to obtain an output in the form of a current signal proportional to the product of the supply voltage "U" by the current "I" which determines the intensity of the mag-netic field being converted by the proposed device into an electric signal. In case the supply voltage "U" is set equal to a voltage drop across the ohmic-inductance load having the current "I"
flowing through it the output of the circuit will be proportional to the power consumed by the load.
lG Fig. 9 presents a version of the device for converting the intensity of a magnetic field into an electric signal accord-ing to the invention which comprises a control magnetizing coil 27 connected, via an amplifier-converter 28, to the resistance strain gauges 5, 9, 12, 13. This design of the proposed deviee makes it possible to obtain a feedback loop using the position of the ferromagnetic plates 1 and 2 as the source of a feedback signal which can be either positive or negative, which allows to vary the characteristics of convert:ing the intensity of a mag-netie field into an eleetrie signal. In particular the deviee ean operate as a null-indicator. However, in this case it is re~uired that the electromagnetic field generated by the control magnetizing coil 27 should compensate for the effect of the ex-ternal magnetic field to be eonverted into an eleetric signal.
If there are several control magnetizing coils (not shown in Fig.
9) the displacement of the ferromagnetic plates 1 and 2 and their resultant position will be determined by the sum (or difference) effect of the coils.
In another version of the embodiment of Fig.-9, the control magnetizing coil 27 is connected, via the amplifier-con-verter 28, to an a-c voltage source, thereby providing for periodie variations in the resistance of the strain gauges 5, 9, 12, 13 and enabling a-c amplifiers to be used for hand~ing signals from the - 10 - `
7~
strain gauges.
The device for converting the intensity of a magnetic or an electromagnetic field into an electrlc signal shown in Figs. 1 and 2 operates as follows.
As soon as a control signal in the form of a longitudinal or a transverse magnetic or electromagnetic field is applied to - a system of ferromagnetic plates 1 and 2 the latter will start approaching each other and with the further increase of the control signal they will diverge, provided that the initial gap and the amount of overlapping between the ferromagnetic plates 1 and 2 exceed certain limiting values, i.e. the values at which the ferromagnetic plates 1 and 2 still contact each other. In case the above requirements are not met the proposed device will operate within the time interval from the moment the ferromagnetic plates 1 and 2 start approaching each other till the moment when they start moving with a jump to contact each other. In any case, however, the above mutual approach of the ferromagnetic plates 1 and 2 is accompanied by their resilient bending strain since ~; they are rigidly fixed in the supports 3 and 4. The outer sur-faces of the ferromagnetic plates 1 and 2 expand while the inner ones contract. In the particular case of cantilever arrangement of the ferromagnetic plates 1 and 2 the deformation section sub-jected to the maximum strain will ~e located in the immediate vicinity to the point where the ferromagnetic plate is fixed in the support 3. It is at this section that the resistance strain gauge should be located. A properly selected and mounted re-sistance strain guage will vary its resistance in proportion to the displacement of the free end of the ferromagnetic plate 1.
The variations of the resistance of the strain gauge 5 are sensed by the measuring circuit 8 so that its output indicates the intensity of the magnetic or electromagnetic field.
The operation of the version of the proposed device as 7~
shown in Fig. 3 is similar to that of the version presented in Figs. l and 2. However, the use of complementary resistance strain guage 9 makes it possible to compensate for temperature errors and to raise the level of the useful signal in any of the known ways.
The operation of the device for converting the intensi-ty of a magnetic or electromagnetic field into an electric signal arranged as shown in Fig. 4 is similar to that of the previous version of the device. In order to raise the level of the output still higher and to reduce the error to the minimum it is neces-sary to select the resistance strain gauges 5, 9, 12 and 13 so that they have similar responses and to install the ferromagnetic plates 1 and 2 symmetrically so as their free ends bend to one and the same extent while the resistances of the strain gauges 5, 13 and 9, 12 are equal.
The operation of the device arranged as shown in Fig. 5 is basically the same as that of the previous version. The fact that the inside of the device is protected with a casing allows to stabilize its response to a certain extent against variations of the amount of dust, gas and other ingredients of the environ-ment. The major difference, however, consists in-the use of the deformation suffered by the membranes l9 and 20 performing the functions of resilient elements. The ferromagnetic plates l and
2 and the membranes l9, 20 in the device are designed so that the increase of the control signal represented by a longitudinal or transverse magnetic or electromagnetic field will not result in a resilient bending strain of the ferromagnetic plates l and 2 that are to approach each other, while the deformation of said membranes will have the form of a waveshape bend. In this case tne maximum strain sections in every membrane l9 and 20 will be located at the points where they are fixed in the butt-ends of the casing 18 and in the immediate vicinity to the place where the f~2~ - 12 -07~
ferromagnetic plates 1 and 2 are rigidly fixed in the membranes 19 and 20. It is at this sections that the resistance strain gauges 5, 9, and 12, 13 are to be located. Properly selected and mounted resistance strain gauges 5, 9, 12, 13 will vary their resistances in proportion to the displacement of the free ends of the ferromagne~ic plates 1 and 2.
The operation of the device designed according to the invention as shown in Fig. 6 is basically similar to that of the device versions presented in Figs. 1 and 2. The.only difference however consists in that the control signal represented by a longitudinal magneti.c field affecting the system of the ferro-magnetic plates 1 and 2 is generated by a direct current flowing through the current conduit 21. The use of copper to make the casing 18 allows to reduce errors caused by expected var.iations of the current I. The device will exhibit the maximum sensitivity when the longitudinal axis of the ferromagnetic plates 1, 2 is orthoc30nal to that of the current conduit 21, and the mimimum sensitivity when the above axes are arranged parallel to each other. In case the electromagnetic fields to be converted sat~lrate the ferromagnetic plates 1 and 2 of the device the casing 18 shall be turned into a position where there-would be no saturation of the ferromagnetic plates 1 and 2. The above version of the device according to the invention permits to reliably and accurately convert strong direct currents (tens and hundreds of kiloampers) into electric signals as increments of the re-sistance ratings of the strain gauge 5.
The operation of the device designed as shown in Fig. 7 is basically similar to that of its version presented in Figs. 1 and 2. The difference, however, consists in that the control signal represented by a longitudinal (o~: transyerse) magnetic field that affects the system of the ferromagnetic plates 1 and 2 is generated by the permanent magnet 23. The displacement of the permanent magnet 23 will vary the intensity of the magnetic field to be converted by the ferromagnetic plates 1 and 2 and the re-sistance strain gauge 5 into an electric signal. In case it is required to determine discrete displacements of the permanent mag-net 23 when, for instance, the amount of the production is counted piece by piece, tlle resistance strain gauge 5 will be connected, via an amplifier-converter, to a counter of the dis-cretely varying resistance of the strain gauge 5 (the amplifier-converter and the counter are not shown in the drawing).
The circuit wherein the resistance strain gauges and the measuring circuit are interconnected as sho~m in Fig. 8 will operate in case the ferromagnetic plates 1 and 2 are being dls-placed and the resistance ratings of the strain gauges 5, 9 and 12, 13 are changing.
Since the resistance strain gauges 5 and 9 as well as 12 and 13 are subjected to deformation effects caused by the dis-placement of the ferromagnetic plates 1 and 2, the deformations being of opposite signs, their arrangement in adjacent arms of the bridge will ensure the maximum sensitivity of the circuit with respect to the intensity of the magnetic or electromagnetic field to be converted (the sensitivity of the circuit is the ratio between the relative increment of the current àt the output of the bridge to the relative variation of the intensity of the magnetic or electromagnetic field). The initial adjustment of the bridge requires that the resistance strain gauges 5, 9, 12, 13 snould be accurately selected. However this adjustment could ~e facilitated by means of adding a complementary balancing re-sistor to the circuit of the device (not shown in the drawing).
The operation of the version of the device presented in Fig. 9 depends on the mode of converting the intensity of a mag-netic or electromagnetic field into an electric signal. This mode can be eitller continuous or relay-like. In the continuous con-version mode with negative feedback the output of the amplifier-converter 28 is applied to the control magnetizing coil 27 which forces the ferromagnetic plates 1 and 2 to return to their initial positions since the electromagnetic field generated by the control coil 27 will compensate for the effect of the magnetic or electro-magnetic field to be converted. This mode of operation of the device ensures high accuracy and sensitivity of the conversion process. In the relay-like conversion mode with negative feed-back the output of the amplifier-converter 28 is applied to the control magnetizing coil 27 in a manner similar to that described above. However the shape and the duration of the signal should be different.
The operation of the device discussed herein is intended to obtain a commutation mode that would be free from vibration and ensure the optimum rate of commutation whereat the time required for the ferromagnetic plates 1 and 2 to shift from one stable position into another will be minimal. The proposed mode of the operation of the device is based upon the theory and methods of optimal control and a complement part of them which is known as dynamic programming. In order to obtain the above effect the control action represented by the number of ampere-turns should be made as high as possible. The ferromagnetic plates 1 and 2 to be closed are accelerated to the maximum speed and then the control action is dropped in a jump to the zero level. Thus, the ferromagnetic plates 1, 2 are "self-braked" and close at a zero speed. After that the control action is generated again to ensure that the ferromagnetic plates 1 and 2 remain in the closed position. The value of the speed at which the ferromagnetic plates 1,2 are displaced and their positions are determined with the help of data provided by the resistance strain gauges 5, 9 12 and 13.
ThP embodiment in which the control magnetizing coil LQ7~
27 is connected to an a-c voltage source via the amplifier- -converter 28 operates as follows. The amplitude and frequency of the supply a-c voltage are set in such a manner as to provide for forced oscillations of the ferromagnetic plates 1 and 2 as well as periodic variations in the resistance of the strain gauges 5, 9, 12, 13. In the presence of an invariable or slowly variable control action in the form of the magnetic (electromagne-tic) field intensity, amplitude modulation of periodically varying resistances of said strain gauges takes place.
ferromagnetic plates 1 and 2 are rigidly fixed in the membranes 19 and 20. It is at this sections that the resistance strain gauges 5, 9, and 12, 13 are to be located. Properly selected and mounted resistance strain gauges 5, 9, 12, 13 will vary their resistances in proportion to the displacement of the free ends of the ferromagne~ic plates 1 and 2.
The operation of the device designed according to the invention as shown in Fig. 6 is basically similar to that of the device versions presented in Figs. 1 and 2. The.only difference however consists in that the control signal represented by a longitudinal magneti.c field affecting the system of the ferro-magnetic plates 1 and 2 is generated by a direct current flowing through the current conduit 21. The use of copper to make the casing 18 allows to reduce errors caused by expected var.iations of the current I. The device will exhibit the maximum sensitivity when the longitudinal axis of the ferromagnetic plates 1, 2 is orthoc30nal to that of the current conduit 21, and the mimimum sensitivity when the above axes are arranged parallel to each other. In case the electromagnetic fields to be converted sat~lrate the ferromagnetic plates 1 and 2 of the device the casing 18 shall be turned into a position where there-would be no saturation of the ferromagnetic plates 1 and 2. The above version of the device according to the invention permits to reliably and accurately convert strong direct currents (tens and hundreds of kiloampers) into electric signals as increments of the re-sistance ratings of the strain gauge 5.
The operation of the device designed as shown in Fig. 7 is basically similar to that of its version presented in Figs. 1 and 2. The difference, however, consists in that the control signal represented by a longitudinal (o~: transyerse) magnetic field that affects the system of the ferromagnetic plates 1 and 2 is generated by the permanent magnet 23. The displacement of the permanent magnet 23 will vary the intensity of the magnetic field to be converted by the ferromagnetic plates 1 and 2 and the re-sistance strain gauge 5 into an electric signal. In case it is required to determine discrete displacements of the permanent mag-net 23 when, for instance, the amount of the production is counted piece by piece, tlle resistance strain gauge 5 will be connected, via an amplifier-converter, to a counter of the dis-cretely varying resistance of the strain gauge 5 (the amplifier-converter and the counter are not shown in the drawing).
The circuit wherein the resistance strain gauges and the measuring circuit are interconnected as sho~m in Fig. 8 will operate in case the ferromagnetic plates 1 and 2 are being dls-placed and the resistance ratings of the strain gauges 5, 9 and 12, 13 are changing.
Since the resistance strain gauges 5 and 9 as well as 12 and 13 are subjected to deformation effects caused by the dis-placement of the ferromagnetic plates 1 and 2, the deformations being of opposite signs, their arrangement in adjacent arms of the bridge will ensure the maximum sensitivity of the circuit with respect to the intensity of the magnetic or electromagnetic field to be converted (the sensitivity of the circuit is the ratio between the relative increment of the current àt the output of the bridge to the relative variation of the intensity of the magnetic or electromagnetic field). The initial adjustment of the bridge requires that the resistance strain gauges 5, 9, 12, 13 snould be accurately selected. However this adjustment could ~e facilitated by means of adding a complementary balancing re-sistor to the circuit of the device (not shown in the drawing).
The operation of the version of the device presented in Fig. 9 depends on the mode of converting the intensity of a mag-netic or electromagnetic field into an electric signal. This mode can be eitller continuous or relay-like. In the continuous con-version mode with negative feedback the output of the amplifier-converter 28 is applied to the control magnetizing coil 27 which forces the ferromagnetic plates 1 and 2 to return to their initial positions since the electromagnetic field generated by the control coil 27 will compensate for the effect of the magnetic or electro-magnetic field to be converted. This mode of operation of the device ensures high accuracy and sensitivity of the conversion process. In the relay-like conversion mode with negative feed-back the output of the amplifier-converter 28 is applied to the control magnetizing coil 27 in a manner similar to that described above. However the shape and the duration of the signal should be different.
The operation of the device discussed herein is intended to obtain a commutation mode that would be free from vibration and ensure the optimum rate of commutation whereat the time required for the ferromagnetic plates 1 and 2 to shift from one stable position into another will be minimal. The proposed mode of the operation of the device is based upon the theory and methods of optimal control and a complement part of them which is known as dynamic programming. In order to obtain the above effect the control action represented by the number of ampere-turns should be made as high as possible. The ferromagnetic plates 1 and 2 to be closed are accelerated to the maximum speed and then the control action is dropped in a jump to the zero level. Thus, the ferromagnetic plates 1, 2 are "self-braked" and close at a zero speed. After that the control action is generated again to ensure that the ferromagnetic plates 1 and 2 remain in the closed position. The value of the speed at which the ferromagnetic plates 1,2 are displaced and their positions are determined with the help of data provided by the resistance strain gauges 5, 9 12 and 13.
ThP embodiment in which the control magnetizing coil LQ7~
27 is connected to an a-c voltage source via the amplifier- -converter 28 operates as follows. The amplitude and frequency of the supply a-c voltage are set in such a manner as to provide for forced oscillations of the ferromagnetic plates 1 and 2 as well as periodic variations in the resistance of the strain gauges 5, 9, 12, 13. In the presence of an invariable or slowly variable control action in the form of the magnetic (electromagne-tic) field intensity, amplitude modulation of periodically varying resistances of said strain gauges takes place.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for converting the intensity of a magnetic or electromagnetic field into an electric signal comprising:
- two ferromagnetic plates performing the functions of movable element;
- two supports with said ferromagnetic plates fixed with one end in each of said supports respectively;
- free ends of said ferromagnetic plates facing each other and arranged so that there is a gap between them and so that they overlap each other at a section located in the immediate vicinity to their said free ends;
- a deformation section located in the immediate vici-nity to the place where every said ferromagnetic plate is fixed in one of said respective supports;
- at least one resistance strain gauge mounted on said deformation section to perform the function of an element sensing the relative displacement of said free ends of said ferromagnetic plates;
- a measuring circuit to which said resistance strain gauge is connected.
- two ferromagnetic plates performing the functions of movable element;
- two supports with said ferromagnetic plates fixed with one end in each of said supports respectively;
- free ends of said ferromagnetic plates facing each other and arranged so that there is a gap between them and so that they overlap each other at a section located in the immediate vicinity to their said free ends;
- a deformation section located in the immediate vici-nity to the place where every said ferromagnetic plate is fixed in one of said respective supports;
- at least one resistance strain gauge mounted on said deformation section to perform the function of an element sensing the relative displacement of said free ends of said ferromagnetic plates;
- a measuring circuit to which said resistance strain gauge is connected.
2. A device as claimed in Claim 1, wherein the field source is made as a current conduit and which comprises:
- an assembly for rotating the axis of said resistance strain gauge with respect to that of said current conduit coupled rigidly to said supports.
- an assembly for rotating the axis of said resistance strain gauge with respect to that of said current conduit coupled rigidly to said supports.
3. A device as claimed in Claim 1 comprising:
- a permanent magnet mounted so that it can be rotated with respect to said ferromagnetic plates;
- a mechanism for displacing said permanent magnet with respect to said ferromagnetic plates so as to vary the resistance of said resistance strain gauge the value of which serves as an additional indication of the position of said permanent magnet.
- a permanent magnet mounted so that it can be rotated with respect to said ferromagnetic plates;
- a mechanism for displacing said permanent magnet with respect to said ferromagnetic plates so as to vary the resistance of said resistance strain gauge the value of which serves as an additional indication of the position of said permanent magnet.
4. A device as claimed in Claim 1, comprising:
- an a-c voltage source;
- an amplifier-converter having an input connected to said a-c voltage source and an output;
- a control magnetizing coil connected to said output of said amplifier-converter, the electromagnetic field of said coil periodically varying the resistance of said resistance strain gauge.
- an a-c voltage source;
- an amplifier-converter having an input connected to said a-c voltage source and an output;
- a control magnetizing coil connected to said output of said amplifier-converter, the electromagnetic field of said coil periodically varying the resistance of said resistance strain gauge.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA300,619A CA1101071A (en) | 1978-04-06 | 1978-04-06 | Device for converting intensity of magnetic or electromagnetic field into electric signal |
| FR7813514A FR2425647A1 (en) | 1978-04-06 | 1978-05-08 | Magnetic field intensity to electrical signal converter - utilises extensometer resistances to measure deformation of ferromagnetic blades |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA300,619A CA1101071A (en) | 1978-04-06 | 1978-04-06 | Device for converting intensity of magnetic or electromagnetic field into electric signal |
| FR7813514A FR2425647A1 (en) | 1978-04-06 | 1978-05-08 | Magnetic field intensity to electrical signal converter - utilises extensometer resistances to measure deformation of ferromagnetic blades |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1101071A true CA1101071A (en) | 1981-05-12 |
Family
ID=71083315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA300,619A Expired CA1101071A (en) | 1978-04-06 | 1978-04-06 | Device for converting intensity of magnetic or electromagnetic field into electric signal |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1101071A (en) |
| FR (1) | FR2425647A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109582079A (en) * | 2018-12-14 | 2019-04-05 | 北京理工大学 | The regulating device of the distribution of the regulating device and magnetic current volume array of magnetic field strength |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2644897B1 (en) * | 1989-03-21 | 1991-07-05 | Crouzet Sa | FLAME BEAM MICROMAGNETOMETER |
| KR102654757B1 (en) * | 2019-02-07 | 2024-04-04 | 현대자동차주식회사 | Clutch current control circuit and electric control valve having the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3349323A (en) * | 1964-08-19 | 1967-10-24 | Robert D Mullen | Apparatus and methods employing magnetic reed switches and static and varying bias fields for detecting magnetic phenomena |
| FR1451481A (en) * | 1965-07-20 | 1966-01-07 | Device for detecting a magnetic field | |
| DE2146339B2 (en) * | 1971-09-16 | 1975-04-03 | Industrie-Automation Gmbh & Co, 6900 Heidelberg | Electromechanical force or pressure transducer |
| US3994161A (en) * | 1975-06-11 | 1976-11-30 | Trozera Thomas A | Load cell |
-
1978
- 1978-04-06 CA CA300,619A patent/CA1101071A/en not_active Expired
- 1978-05-08 FR FR7813514A patent/FR2425647A1/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109582079A (en) * | 2018-12-14 | 2019-04-05 | 北京理工大学 | The regulating device of the distribution of the regulating device and magnetic current volume array of magnetic field strength |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2425647B1 (en) | 1980-10-31 |
| FR2425647A1 (en) | 1979-12-07 |
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