NZ761649B2 - Inductive sensor - Google Patents
Inductive sensor Download PDFInfo
- Publication number
- NZ761649B2 NZ761649B2 NZ761649A NZ76164918A NZ761649B2 NZ 761649 B2 NZ761649 B2 NZ 761649B2 NZ 761649 A NZ761649 A NZ 761649A NZ 76164918 A NZ76164918 A NZ 76164918A NZ 761649 B2 NZ761649 B2 NZ 761649B2
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- New Zealand
- Prior art keywords
- sensor
- coil
- winding part
- cable
- winding
- Prior art date
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- 230000001939 inductive effect Effects 0.000 title claims abstract description 19
- 238000004804 winding Methods 0.000 claims abstract description 47
- 238000011156 evaluation Methods 0.000 claims description 6
- 241000229754 Iva xanthiifolia Species 0.000 claims description 4
- 230000005672 electromagnetic field Effects 0.000 abstract description 9
- 238000005259 measurement Methods 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61B—RAILWAY SYSTEMS; EQUIPMENT THEREFOR NOT OTHERWISE PROVIDED FOR
- B61B12/00—Component parts, details or accessories not provided for in groups B61B7/00 - B61B11/00
- B61B12/06—Safety devices or measures against cable fracture
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/001—Constructional details of gauge heads
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/023—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring distance between sensor and object
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
- G01D5/22—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils
- G01D5/2208—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils by influencing the self-induction of the coils
- G01D5/2216—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils by influencing the self-induction of the coils by a movable ferromagnetic element, e.g. a core
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
-
- 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
- G01R33/028—Electrodynamic magnetometers
- G01R33/0283—Electrodynamic magnetometers in which a current or voltage is generated due to relative movement of conductor and magnetic field
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/58—Calibration of imaging systems, e.g. using test probes, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
- G01V3/101—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil
- G01V3/102—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil by measuring amplitude
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/945—Proximity switches
- H03K17/95—Proximity switches using a magnetic detector
- H03K17/9502—Measures for increasing reliability
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/945—Proximity switches
- H03K17/95—Proximity switches using a magnetic detector
- H03K17/952—Proximity switches using a magnetic detector using inductive coils
Abstract
order to make an inductive sensor insensitive to external electromagnetic fields, provision is made for the sensor coil (3) to be embodied with a first winding part (6a) and a second winding part (6b) connected thereto, wherein the first winding part (6a) and the second winding part (6b) are wound in the opposite sense to one another and the first winding part (6a) is connected to a first coil connector (5a) and the second winding part (6b) is connected to a second call connector (5b). The use of a sensor of this kind for monitoring the position of a cable of a cable car system. d in the opposite sense to one another and the first winding part (6a) is connected to a first coil connector (5a) and the second winding part (6b) is connected to a second call connector (5b). The use of a sensor of this kind for monitoring the position of a cable of a cable car system.
Description
Inductive sensor
The present ion relates to an inductive sensor comprising a sensor coil having two coil
terminals and a sensor tion unit which is connected to the two coil terminals, and the
use of a sensor of this kind for monitoring the position of a cable of a cable car system.
Contactless inductive sensors are often used for distance measurement. In this case, the
sensor can be designed as a proximity sensor that works from a certain distance of the
sensor from the measured object, or the distance from the object can also be output by the
sensor as a value. Sensors of this kind are often used to monitor particular functionalities in
machines and systems.
An inductive sensor uses a coil to generate an electromagnetic field which is nced by
the measured object. The influence can be recorded and evaluated using measurement
technology. One exemplary embodiment is an inductive sensor designed as an eddy current
. In this case, an oscillator tes an electromagnetic alternating field that
emanates from the active surface of the sensor. Eddy currents are induced in each
electrically conductive object in the vicinity of the active surface depending on the distance of
the object from the active surface, which eddy currents draw energy from the oscillator and
can be detected as power losses at the coil input.
One particular application for an inductive sensor is monitoring the position of the circulating
traction cable of a cable car system. The traction cable is guided along the route on the cable
car supports via rollers of a roller battery. The position of the traction cable relative to the
rollers of the roller battery can be monitored using an ive sensor. In so doing, it is
possible to fy both the lateral deflection of the traction cable, which can indicate, for
example, the traction cable popping out of the roller, and an insufficient distance from the
axis of on of the roller, which indicates that the traction cable is eating into the running
surface of the roller, for example when the roller is d. Monitoring the position of the
cable is an important safety function of a cable car system and can lead to a reduction in the
conveying speed or to a forced shutdown of the cable car. When monitoring the position of
the cable, the on cable which is ed as a steel cable is used as the object to be
measured and the sensor is arranged so as to be nary in the region of the traction
cable. This ation requires high sensitivity of the inductive sensor in order to be able to
detect the position of the cable with ient accuracy.
Inductive sensors of this kind are disadvantageous in that each external (electro)magnetic
ating field in the vicinity of the sensor induces an electrical voltage in the coil of the
sensor. This overvoltage impressed from the outside of course also interferes with the
measurement. Besides this, the sensor must of course also have sufficient overvoltage
resistance. Radio waves in the vicinity of the sensor will only induce low voltages and will
ily negatively influence the ement and reduce the sensitivity of the
measurement. However, if lightning strikes the traction cable of the cable car, this s a
current flow in the traction cable, thereby generating strong magnetic fields around the
traction cable. Lightning currents of this kind can cause very high electrical voltages to be
injected into the coil of the sensor. Studies have shown that, in the event of typical lightning
currents, induced voltages of several kilovolts can occur at the outlets of the coil. These high
voltages can destroy the coil and/or destroy the subsequent sensor electronics.
Of course, it is possible to ent electronic lightning tion or protection against
overvoltage in the , but this in turn interferes with the measuring circuit and thus limits
the sensitivity of the sensor.
The problem addressed by the invention is therefore that of providing an ive sensor
which is insusceptible to external omagnetic fields.
This problem is solved by the sensor coil being designed so as to have a first winding part
and a second winding part connected thereto, the first winding part and the second winding
part being wound in opposite directions and the first winding part being connected to a first
coil terminal and the second winding part being connected to a second coil al. By
means of g in opposite directions, voltages induced in the winding parts compensate
for one another at least in part, and therefore only low or no overvoltages can occur at the
coil terminals. This does not interfere or only slightly interferes with the ement such
that a high sensitivity of the measurement can be achieved. Likewise, further measures for
overvoltage protection t overvoltage caused by external electromagnetic fields, which
measures could interfere with the measuring circuit, are not required. This means that the
sensor can also be protected t very high external electromagnetic fields, such as can
occur in the event of lightning currents through conductors, for example. A sensor of this kind
is therefore particularly le for outdoor applications. A particularly advantageous
application for a sensor of this kind is therefore use in a cable car system, for example for
monitoring the position of the traction cable.
In one simple embodiment, the sensor coil is continuously wound in a figure of eight. A
sensor coil of this kind is particularly easy to manufacture.
A sensor coil which comprises a first single coil as the first winding part that is connected in
series with a second single coil as the second winding part is particularly advantageous. By
means of this embodiment, high differential voltages between individual windings of the
sensor coil can be d, which reduces the risk of voltage owns.
If the first single coil and the second single coil are wound helically, a particularly flat sensor
coil can be created, which is advantageous for use in the sensor.
In the following, the present invention will be explained in greater detail with reference to
Fig. 1 to 5, which show exemplary advantageous embodiments of the invention in a
tic and non-limiting manner. In the drawings:
Fig. 1 shows the operating principle of a contactless inductive sensor;
Fig. 2 shows a first embodiment of a sensor coil according to the invention;
Fig. 3 shows a further embodiment of a sensor coil according to the invention;
Fig. 4 shows a further ment of a sensor coil according to the invention; and
Fig. 5 shows the use of a sensor coil according to the invention for monitoring the
position of a cable in a cable car system.
The principle of an inductive sensor for ce measurement is shown in Fig. 1. A sensor
coil 3 tes an electromagnetic field which interacts with an electrically conductive
object 4. This interaction can be detected and evaluated at the outlets 5 of the sensor coil 3
by a sensor evaluation unit 2, for example via the coil voltage u and/or the coil current i. In
one embodiment as an eddy current sensor, an oscillator in the sensor evaluation unit 2
generates a high-frequency alternating voltage which is applied to the sensor coil 3 and
generates a high-frequency ating field. This high-frequency alternating field generates
eddy currents in an object 4 in the region of nce of the sensor 1, which currents draw
energy from the omagnetic alternating field, thereby reducing the height of the
oscillation amplitude of the oscillator voltage. This change in oscillation ude is
ted by the sensor evaluation unit 2. If embodied as a proximity switch, the sensor 1
either supplies a high level or low level as an output signal A or the output signal A
represents a measure of the distance between the sensor coil 3 and the object 4. In the latter
case, the output signal A can be analog, for example an ical voltage, or digital.
However, the principle according to which the inductive sensor 1 operates or how the sensor
evaluation unit 2 is designed or how it is evaluated or in what way the output signal A is
output is irrelevant to the invention.
The invention is based on a particular embodiment of the sensor coil 3. According to the
invention, the sensor coil 3 is designed so as to have a first winding part 6a and a second
g part 6b connected thereto, the first winding part 6a and the second winding part 6b
being wound in opposite directions. A first coil terminal 5a is connected to the first winding
part 6a and a second coil terminal 5b is connected to the second winding part 6b. As a result
of winding the two winding parts 6a, 6b in te directions, external electromagnetic fields
induce opposite voltages in the two winding parts 6a, 6b, which voltages compensate for one
another at least in part. In this way, a icantly lower overvoltage is produced by external
omagnetic fields at the coil terminals 5a, 5b. If the two winding parts 6a, 6b are identical
except for the winding direction, the voltages induced therein substantially cancel one
another out and there are no or only extremely low overvoltages at the coil terminals 5a, 5b.
This s at least to a homogeneous external electromagnetic field, but can usually be
assumed for typical applications. However, even in the case of an inhomogeneous external
field, the two induced es would largely compensate for one another.
The sensor coil 3 can be wound continuously or can also consist of two single coils
connected in series.
In a first embodiment according to Fig. 2, the sensor coil 3 is continuously wound in a figure
of eight. For the sake of simplicity, only two windings per g part 6a, 6b are shown in
Fig. 2, but the sensor coil 3 can of course also have more gs. As a result of the figure-
of-eight-shaped winding, the two resulting winding parts 6a, 6b have opposite winding
directions.
A similar result is obtained by first winding a coil, compressing the wound coil at one point
and then rotating one of the resulting winding parts 6a by 180° with respect to the other
winding part 6b. This likewise produces a continuously wound figure-of-eight-shaped sensor
coil 3 which has two winding parts 6a, 6b wound in opposite directions.
A further embodiment is produced when two single coils 7a, 7b wound in opposite directions
are ted in series. In this case, the two single coils 7a, 7b each form a winding
part 6a, 6b in the sensor coil 3, as shown in Fig. 3.
In one particularly advantageous embodiment, the two single coils 7a, 7b forming the winding
parts 6a, 6b are wound helically, as shown in Fig. 4. In this case, the windings of the g
parts 6a, 6b are preferably arranged in one plane. The winding parts 6a, 6b can in this case
be wound as a single-layer helix or also as a multi-layer helix. In an embodiment of this kind,
the sensor coil 3 can be particularly flat.
The advantage of the embodiment comprising single coils 7a, 7b connected in series
compared to a continuously wound sensor coil 3 is that the voltage ences between
adjacent windings of the sensor coil 3 are always small, and therefore no undesirable voltage
breakdowns can occur which would destroy the sensor coil 3. In the case of a figure-of-eightshaped
embodiment, there may be large e ences between individual windings, in
particular in the region of the ng point of the individual windings, for which reason the
risk of voltage owns is higher in this case and therefore higher insulation measures
have to be taken according to the stances.
In order to avoid the electromagnetic excitation fields generated by the winding parts 6a, 6b
not completely or partially cancelling one another out, the two winding parts 6a, 6b are
arranged one next to the other in one plane, as shown in the figures, and not one behind the
other. This plane is also referred to as the active surface 8 (Fig. 1) of the sensor 1, from
which surface the omagnetic fields emanate. In this case, the object 4 is arranged
opposite the active surface 8 of the sensor 1 in order to reach the region of influence of the
electromagnetic fields.
The sensor 1 can also be used in safety-critical applications, and therefore the sensor 1 can
also be designed to meet functional safety requirements (e.g. a safety requirement level in
accordance with IEC 61508). For example, the sensor 1 could be designed so as to have a
two-channel sensor tion unit 2, it also being possible to provide mutual checks on the
channels. Of course, other or additional known measures for achieving functional safety are
also conceivable.
One advantageous application of the inductive sensor 1 according to the invention is
monitoring the position of a cable of a cable car system 10, as shown in Fig. 5. The cable car
system 10 is only shown in part and as far as necessary in Fig. 5, since the basic structure of
a cable car system in various embodiments is well known. In this case, the sensor 1 is
arranged, for example, so as to be stationary in the region of a roller battery 11 on a cable
car support comprising a number of cable rollers 12 and so as to be in contactless ive
connection with a traction cable 13. Of course, the sensor 1 can also be arranged at any
other point in the cable car system 10 in order to monitor the position of the traction cable 13.
‘In operative connection’ in this case means, of course, that the traction cable 13, as the
object 4, iently influences the electromagnetic field of the sensor coil 3 of the sensor 1
that a change in position of the traction cable 13 relative to the sensor 1 can be detected and
evaluated by the sensor tion unit 2. For this purpose, the traction cable 13 is arranged
opposite the active e 8 of the sensor 1. The output signal A from the sensor 1 is
itted to a cable car l unit 20 and used in said unit to control the cable car
system 10. The transmission can, of course, be wired or wireless. For example, depending
on the output signal A, the conveying speed of the traction cable 13 can be changed, or the
cable car system 10 can be stopped.
Claims (6)
1. An ive sensor for monitoring the on of a traction cable of a cable car system, 5 the sensor comprising a sensor coil having two coil als and a sensor evaluation unit which is connected to the two coil terminals, wherein the sensor coil is designed so as to have a first winding part and a second winding part connected thereto, the first winding part and the second winding part being wound in opposite directions and the first winding part being connected to a first coil terminal and the second g part being connected to a 10 second coil terminal, and wherein the sensor coil is designed to be operatively connected to the traction cable and the sensor evaluation unit is designed to detect and evaluate a change in position of the traction cable relative to the sensor.
2. An inductive sensor according to claim 1, wherein the sensor coil is continuously wound in a figure of eight. 15
3. An inductive sensor according to claim 1, wherein a first single coil as the first winding part is connected in series with a second single coil as the second winding part.
4. An inductive sensor according to claim 3, wherein the first single coil and the second single coil are wound helically.
5. An inductive sensor according to any one of claims 1 to 4, wherein the two winding parts 20 are arranged one next to the other in one plane.
6. A cable car system sing a traction cable and an inductive sensor according to any one of claims 1 to 5 for monitoring the position of the traction cable. s 1 4 2 A 3
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ATA50711/2017 | 2017-08-25 | ||
AT507112017 | 2017-08-25 | ||
PCT/EP2018/072804 WO2019038397A1 (en) | 2017-08-25 | 2018-08-23 | Inductive sensor |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ761649A NZ761649A (en) | 2021-03-26 |
NZ761649B2 true NZ761649B2 (en) | 2021-06-29 |
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