JP2000351575A - Detection device for disconnection of wirerope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the detection device for the disconnection of a wirerope which can prevent the generation of a residual magnetization on the steel wirerope and also detect the disconnection of the steel wirerope precisely and simply without the necessity of an experience. SOLUTION: This device is provided with a sensor 14 provided with exciting coils 3, 4 and detection coil 5 so as to be wound to the outer periphery of a steel wirerope through a sensor part coil holder, an exciting circuit part 7 provided with a sine wave oscilator 10 for adding an alternating current I0 to the exciting coils 3, 4 of the sensor 14 and a phase shifter 13 for changing the phase of the alternating current I0 from the sine wave oscilator 10, a phase wave detecting circuit 16 for finding out the phase wave detection signal VF based on the detection signal VC from the detection coil 5 and the carrying wave signal VW from the phase shifter 13, a low pass filter 17 for obtaining the disconnection detection signal VL of a low freqency based on the phase wave detection signal VF from the phase wave detecting circuit 16 and an abnormality indication lamp 19 for lighting based on the disconnection detection signal VL from the low pass filter 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rope disconnection detecting device capable of non-destructively inspecting internal wires for disconnection.

[0002]

2. Description of the Related Art There are many types and structures of steel wire ropes, and they are appropriately selected according to the application.

[0003] The most commonly used cranes and the like at present are strands formed by twisting a large number of strands to form strands (strands). However, in recent years, a considerable number of breakage accidents of the strand-type steel wire rope have occurred.

[0004] When a steel wire rope having a steel core breaks, it is characterized in that damage proceeds in advance inside, rather than outside, as compared with a conventional fiber core rope. For this reason, the breakage of the wire generated from the inside gradually progresses to the outside, and in many cases, eventually leads to the cutting of the steel wire rope. It has been pointed out that it is impossible to evaluate the damage. For this reason, in recent years, an inspection device for inspecting whether or not the internal element wire is broken due to non-destruction is required.

An X-ray inspection apparatus is most suitable as an apparatus for inspecting whether or not an internal element wire is broken due to non-destruction. However, an X-ray inspection apparatus is expensive and requires handling. However, there is a problem that specialized technology is required and it cannot be easily used.

For this reason, as shown in FIG. 7, there has been proposed a wire rope disconnection detecting device which detects leakage magnetic flux by electromagnetic flaw detection as a device which can be easily used.
In the apparatus shown in FIG. 7, permanent magnets d and e for magnetizing the steel wire rope b are mounted on a sensor holder c having a split yoke a and capable of surrounding the outer periphery of the steel wire rope b. A detection coil provided at a predetermined interval in the longitudinal direction of the steel wire rope b, and further detecting a magnetic flux leaking from the steel wire rope b at an intermediate portion of the permanent magnets d and e in the longitudinal direction of the steel wire rope b. f is provided so as to surround the steel wire rope b.

According to the wire rope disconnection detecting device shown in FIG. 7, the steel wire rope b is strongly magnetized by the permanent magnets d and e. If there is a disconnection in the steel wire rope b, magnetic flux leaks from the broken portion. This leakage magnetic flux is detected by the detection coil f, and the detection coil f
By processing the measurement signal detected in step (1), the disconnection of the steel wire rope b is detected. In addition,
In FIG. 7, g and h are magnetic fluxes.

[0008]

However, the above-described wire rope disconnection detecting device has the following problems.

I) Since the yoke a is used, in order to efficiently magnetize the steel wire rope b, strong permanent magnets d and e are required. For this reason, residual magnetization may occur in the steel wire rope b and iron powder or the like may adhere, and during operation after inspection, the steel wire rope b may be damaged by friction with the iron powder or the like.

Ii) Since the S / N ratio (ratio of the signal S to the noise N) of the measurement signal detected by the detection coil f is low and the number of noise signals is large, it is necessary to determine and extract disconnection information based on the disconnection. It is very difficult and therefore requires experience to read the signal and is not readily available.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and aims to prevent the occurrence of residual magnetization in a steel wire rope, and to accurately and easily detect a break in the steel wire rope without requiring experience. An object of the present invention is to provide a wire rope disconnection detecting device that can perform the above-described operation.

[0012]

In order to solve the above-mentioned problems, a wire rope disconnection detecting apparatus according to the present invention comprises a sensor,
A signal processing circuit having an excitation circuit section and a phase detection circuit section, wherein the sensor is a sensor section coil holder provided on the outer periphery of the steel wire rope so as to be relatively movable with respect to the steel wire rope, and an axis of the sensor section coil holder. A pair of serially connected exciting coils provided to be wound around the outer periphery of the sensor coil holder in the front and rear directions, and leakage of the steel wire rope wound around the outer periphery of the sensor coil holder so as to be located between the front and rear exciting coils. A detection coil configured to detect a magnetic flux, an excitation circuit unit of the signal processing circuit includes a sine wave generator for applying an alternating current to the excitation coil, and a sine wave generator connected in parallel to the excitation coil and A phase shifter adapted to change the phase of the alternating current from the oscillator, and a phase detection circuit of the signal processing circuit, A phase detection circuit that obtains a phase detection signal by multiplying a detection signal from the detection coil by a carrier signal from the phase shifter, and cuts off a high-frequency component from the phase detection signal from the phase detection circuit to convert a low-frequency component signal. A low-pass filter configured to output as a disconnection detection signal, and at least one of an alarm unit that issues an alarm when a disconnection detection signal is output from the low-pass filter and an abnormality display unit that performs an abnormality display. It is a thing.

The present invention also provides a coil winding apparatus having a rotatable shaft and a drivable hollow cylindrical shaft disposed parallel to the shaft and through which a steel wire rope can be inserted. And at one end of the shaft,
A winding coil holder in which a coil is separately wound at three positions in the axial direction is detachably provided, and one end of the hollow cylindrical shaft is divided into a plurality of pieces in the circumferential direction to surround the steel wire rope. A coil detachably provided at one end of a hollow cylindrical shaft and unwound from the winding coil holder can be separately wound at three axial positions so that it can be used as an excitation coil and a detection coil. The winding coil holder is provided.

In the present invention, when there is a break in the steel wire rope, a leakage coil is detected by the detection coil, and this leakage magnetic flux is processed as a detection signal together with the carrier signal to obtain a break detection signal. Alarm is issued from the alarm means or the abnormality display means is displayed based on the information.

In the present invention, since no residual magnetization is generated in the steel wire rope, iron powder or the like does not adhere to the steel wire rope. There is no risk of damage due to wear.

Further, the disconnection detection signal can be easily taken out with a high S / N, so that no experience is required to read the signal and the signal can be easily used.

Furthermore, the sensor is more compact and easier to handle than conventional products, and has a better detection accuracy. Further, it is possible to accurately and reliably detect a break in the steel wire rope regardless of the scanning speed of the steel wire speed. it can.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 6 show an embodiment of the present invention.

1, 2, and 4, reference numeral 1 denotes a non-magnetic sensor coil formed in two pieces and surrounding the outer periphery of the steel wire rope 2 so that the coil can be assembled to the steel wire rope 2. The steel wire rope 2 is a holder that can move in the longitudinal direction with respect to the sensor unit coil holder 1.

Excitation coils 3 and 4 are wound around the outer periphery of the coil holder 1 at both ends in the longitudinal direction. The detection coil 5 can be wound so as to be located therebetween. Thus, the winding directions of the exciting coils 3 and 4 are the same, and the number of turns is the same.

An exciting circuit for exciting the exciting coils 3 and 4 to generate a magnetic flux 6 between the exciting coils 3 and 4 as shown in FIG. 2 and a phase detecting circuit for processing a signal from the detecting coil 5 include: This is shown in FIG. 3, in which 7 is an excitation circuit section, and 8 is a phase detection circuit. Thus, a signal processing circuit is constituted by the excitation circuit section 7 and the phase detection circuit section 8, and the signal processing circuit is housed in the signal processing unit main body 9 shown in FIG.

The excitation circuit unit 7 includes a sine wave oscillator 10 that outputs an AC current I0 = E0sinωt of a reference optimum frequency as an excitation current, and a noise for removing noise from a signal from the sine wave oscillator 10. Filter 1
1; an amplifier 12 for amplifying a signal from the noise filter 11; and a phase shifter 13 arranged in parallel with the amplifier 12 for shifting the phase of the signal from the noise filter 11. Is the sensor 14
The exciting current I0 can be supplied to the exciting coils 3 and 4 connected in series. Here, E0 is voltage, ω is angular velocity, and t is time.

The phase detection circuit 8 detects a detection signal VC (= E1 sin) detected by the detection coil 5 of the sensor 14.
A noise filter 15 for removing noise from (ωt + θ)), a phase detection circuit 16 for multiplying a detection signal from the noise filter 15 and a carrier signal VW from the phase shifter 13 to perform phase detection, and a phase detection circuit 16 A low-pass filter 17 for removing a high frequency component from the phase detection signal VF from
An amplifier 18 for amplifying the disconnection detection signal VL from the low-pass filter 17 to obtain a voltage disconnection detection signal VL 'as shown in FIG.
An analog meter 41 for displaying L ′ and a disconnection signal VL ′
A measuring terminal 42 for outputting a signal to the outside, a judgment circuit 20 for judging that a disconnection detection signal VL ′, which is an analog signal from the amplifier 18, exceeds a certain value (threshold),
There is provided a buzzer 21 that sounds by the digital signal VD from the determination circuit 20.

When detecting breakage of the steel wire rope 2, the exciting coils 3, 4 and the detecting coil 5 are wound around the sensor coil holder 1 as shown in FIGS. For winding the detection coil 5, a coil winding device 22 as shown in FIG. 5 is used.

That is, the frame body 23 of the coil winding device 22 is rotatably provided with a vertical axis 25 via bearings 24 arranged vertically, and a connecting jig 26 is provided at the upper end of the vertical axis 25. , A cylindrical coil holder 27 for winding can be detachably attached. Thus, the coil 28 can be wound around the outer periphery of the winding coil holder 27 at three locations in the vertical direction.

A hollow cylindrical shaft 29 is installed vertically on the frame 23 in parallel with the longitudinal axis 25, and the hollow cylindrical shaft 29 is connected to a rotatable roller 3 disposed above and below the frame 23.
0, the outer periphery of the hollow cylindrical shaft 29 is rotatably supported at four locations in the circumferential direction.
A winding coil holder 31 serving as the sensor unit coil holder 1 shown in FIGS. 1, 2, and 4 is detachably attached.

The winding coil holder 31 is divided into two parts.
By attaching to the upper end of the hollow cylindrical shaft 29, it is configured in a cylindrical shape, and the steel wire rope 2 can be inserted into the coil holder 31 for winding and the hollow cylindrical shaft 29. I have.

The coil 28 unwound from the winding coil holder 27 is wound at three positions in the vertical direction with respect to the winding coil holder 31.

A vertical DC geared motor 32 is disposed on the frame 23, and a pulley 33 for a timing belt is externally fitted and fixed to an upper output shaft of the DC geared motor 32.

The frame body 23 has bearings 34 located at upper and lower positions.
A power transmission longitudinal axis 35 is provided rotatably through the shaft, and a timing belt pulley 36 is externally fitted and fixed to the upper end of the longitudinal axis 35. An endless timing belt 37 is wound around the timing belt pulleys 33 and 36.

A friction drive roller 38 is externally fitted and fixed to the middle portion of the vertical axis 35 in the height direction.
The outer periphery of 8 is in contact with the outer periphery of the intermediate portion in the height direction of the hollow cylindrical shaft 29 so that the hollow cylindrical shaft 29 can be driven to rotate.

The coil 28 is mounted on the coil holder 31 for winding.
In order to fix the steel wire rope 2 inserted into the hollow cylindrical shaft 29 and the winding coil holder 31 when winding the steel wire rope, two portions of the steel wire rope 2 are provided above the winding coil holder 31. A split wire rope fixing bracket 39 can be attached, and one of the split wire rope fixing brackets 39 is fixed to a column 40 erected from the frame 23.

In FIG. 1, reference numeral 41 denotes an analog meter,
2 is a measuring terminal, 43 is an outlet, and in FIG. 5, 44 is a winding counter for the winding coil holder 31 of the coil 28, 45 is a motor code, 46 is a winding counter code, and 47 is an outlet.

Next, the operation of the present invention will be described.

When inspecting the wire break of the steel wire rope 2, the winding coil holder 3 shown in FIG.
1, 2 and 4 to form the sensor coil holder 1 as shown in FIGS.
The winding coil holder 27 around which the coil 28 is wound in three stages is connected to the upper end of the vertical axis 25 via the connection jig 26.

At the upper end of the hollow cylindrical shaft 29 into which the steel wire rope 2 is inserted, a winding coil holder 31 is connected so as to surround the steel wire rope 2 and the steel wire rope 2 is connected to the winding coil holder 31. The steel wire rope 2 is fixed to the frame body 23 by attaching a split wire rope fixing bracket 39.

Further, the coil 28 wound around the winding coil holder 27 in three steps is rewound from the winding coil holder 27 and stopped at the leading end thereof. It winds around the lower three places and drives the DC geared motor 32. Therefore, the power is supplied to the pulley 33 for the timing belt, the timing belt 37, the pulley 36 for the timing belt,
5, transmitted from the friction drive roller 38 to the hollow cylindrical shaft 29, the hollow cylindrical shaft 29 is driven by friction to rotate.

When the hollow cylindrical shaft 29 rotates, the winding coil holder 31 also rotates integrally with the hollow cylindrical shaft 29, so that the coil 28 wound around the winding coil holder 27 becomes the winding coil holder. The longitudinal axis 25 and the winding coil holder 27 are rotated by the tension of the coil 28 on the winding coil holder 31 side, so that the coil 28 is unwound while rotating. The unwound coil 28 is accurately and quickly wound on the winding coil holder 31. Since the number of turns of the coil 28 wound on the winding coil holder 31 is counted by the turn counter 44, the number of turns is also accurate.

When the required number of turns of the coil 28 is wound in three steps on the upper, middle and lower portions of the coil holder 31 for winding, the DC geared motor 32 is stopped and the coil 2 is turned off.
The winding of the coil 8 into the winding coil holder 31 is completed. For this reason, the winding coil holder 31 is removed from the hollow cylindrical shaft 29, and the wire rope fixing bracket 39 for fixing the steel wire rope 2 is also removed.
At this time, the winding coil holder 31 is externally fitted to the steel wire rope 2.

The coil 28 wound around the upper and lower portions of the winding coil holder 31 is connected so that the winding portion is electrically connected in series, and has one end connected to the amplifier of the excitation circuit portion 7. The coil 28 connected to the output side 12 and the other end is grounded, and the coil 28 wound around the middle portion of the winding coil holder 31 has one end connected to the noise filter 11 side of the phase detection circuit section 8 and the other end. The end is grounded (see FIG. 3).

As described above, the sensor 14 in which the excitation coils 3 and 4 and the detection coil 5 are wound around the outer periphery of the coil holder 1 of the sensor unit fitted on the steel wire rope 2 is formed. In addition, the wire rope disconnection detection device is formed by being connected to the phase detection circuit unit 8.

The overall outer shape of the wire rope disconnection detecting device is as shown in FIG. For inspection, the outlet 43 is plugged into a power source, a switch is turned on, and for example, the sensor coil holder 1 is fixed, and the steel wire rope 2 is connected to the sensor coil holder 1.
The inspection is performed by moving the sensor unit coil holder 1 in the longitudinal direction of the steel wire rope 2 without scanning the steel wire rope 2 while moving the steel wire rope 2.

At the time of inspection, the sine wave oscillator 10 shown in FIG.
, An AC current I0 is output as an exciting current, and the exciting current is supplied to the exciting coils 3 and 4 after the noise is removed through the noise filter 11.

For this reason, the exciting coils 3 and 4 are excited, and a magnetic flux 6 is generated in the steel wire rope 2 as shown in FIG. Thus, when the wire of the steel wire rope 2 is not broken, no leakage magnetic flux is generated in the steel wire rope 2 and almost no current flows through the detection coil 5. Is small and stable, and the signal output from the amplifier 18 via the low-pass filter 17 from the phase detection circuit 16 is much smaller than the threshold value. It does not light and the buzzer 21 does not sound. Therefore, in this case, it is determined that no break has occurred in the steel wire rope 2 strand.

When the wire of the steel wire rope 2 is broken, a leakage magnetic flux 6a is generated from the broken portion as shown in FIG. Therefore, when the location where the leakage magnetic flux 6a of the steel wire rope 2 is generated passes through the detection coil 5, the signal VC (E1
sin (ωt + θ)) (here, E1 is a voltage and θ is a phase delay) E1 changes. The noise of the detection signal VC is removed by a noise filter 15 and the detection signal VC is supplied to a phase detection circuit 16.

On the other hand, the alternating current I0 output from the sine wave oscillator 10 is applied to the exciting coils 3 and 4 as described above to act as an exciting current, and the phase shifter 1
3 and the phase shifter 13 outputs a reference signal E
0 sinωt by changing the phase by 0 to 180 degrees
W (= sin ωt) is obtained, and the carrier signal VW is supplied to the phase detection circuit 16.

In the phase detection circuit 16, the detection signal E1 (s
(inωt + θ) and the carrier signal sinωt are multiplied to obtain a phase detection signal VF of E1 sin (2ωt + θ) + E1cosθ, and the obtained phase detection signal VF is output to the low-pass filter 17.

E1 sin of the phase detection signal VF at this time
Since (2ωt + θ) is a high-frequency component and E1cosθ is a DC component, the phase detection signal E1sin (2ωt + θ) +
When E1cos θ is passed through the low-pass filter 17 to cut off high-frequency components, the DC component of the signal is output from the low-pass filter 17 as the disconnection detection signal VL, and the amplifier 1
8 and amplified by the amplifier 18 to obtain a disconnection detection signal VL '(see FIG. 6) which is an analog signal.

The disconnection detection signal VL 'is output from the analog meter 4
1 to display the signal level and at the same time to the discrimination circuit 20. If the strand of the steel wire rope 2 is broken, the disconnection detection signal VL 'has exceeded the threshold value, the discriminating circuit 20 operates, and the buzzer 21 is sounded by the digital signal VD from the discriminating circuit 20. Turn on the abnormality display lamp.

In this way, it is possible to detect non-destructively that the wire of the steel wire rope 2 is broken.

In the embodiment of the present invention, since an alternating current is used to magnetize the steel wire rope 2 and a permanent magnet is not required, no residual magnetization occurs in the steel wire rope 2. Therefore, iron powder or the like does not adhere to the steel wire rope 2, and there is no possibility that the steel wire rope 2 will be damaged by friction of the iron powder or the like during operation after inspection.

In the embodiment of the present invention, the excitation coils 3 and 4 and the detection coil 5 are not attached to the yoke, but are wound around the outer periphery of the steel wire rope 2 via the sensor coil holder 1. Therefore, the disconnection detection signal VL 'can be easily extracted at a high S / N ratio without being affected by the cross-sectional shape and vibration of the steel wire rope 2, and therefore, experience is required to read the signal. It can be easily used without having to use it.

In the sensor 14, the length of the sensor coil holder 1 is about 100 mm, and the total weight is about 500 g. And the detection accuracy is good.

Further, the voltage applied to the excitation coils 3 and 4 is multiplied by a signal detected by the detection coil 5 as a carrier wave, and the obtained signal is processed by a low-pass filter 17 to obtain a disconnection detection signal VL '. Therefore, the scanning speed of the steel wire rope 2 is not affected at all, and the inspection can be performed by moving the wire rope disconnection inspection device without scanning the steel wire rope 2.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.

[0057]

According to the wire rope disconnection detecting apparatus of the present invention, various excellent effects as described below can be obtained.

I) An alternating current is used to magnetize the steel wire rope, and no permanent magnet is required, so that no residual magnetization is generated in the steel wire rope. There is no possibility that the steel wire rope will not be damaged due to friction with iron powder or the like during operation after the inspection.

II) Since the exciting coil is not attached to the yoke but wound around the outer periphery of the steel wire rope via the coil holder, the disconnection signal is not affected by the sectional shape and vibration of the steel wire rope. It can be easily taken out with a high S / N ratio,
Therefore, no experience is required to read the signal, and the signal can be easily used.

III) Since the sensor can be made much more compact than conventional products, it is easy to handle and the detection accuracy is good.

IV) Disconnection of the steel wire rope can be detected accurately and reliably regardless of the scanning speed of the steel wire rope.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall outer shape of a wire rope disconnection detection device of the present invention.

FIG. 2 shows a wire rope disconnection detecting device according to the present invention.
It is a schematic diagram showing the principle of detecting breakage of the strand of a steel wire rope.

FIG. 3 is a block diagram of a signal processing circuit used in the wire rope disconnection detection device of the present invention.

FIG. 4 shows a wire rope disconnection detecting device according to the present invention.
It is a perspective view showing the state where an exciting coil and a detection coil were wound around a sensor part coil holder.

FIG. 5 shows a wire rope disconnection detecting device according to the present invention.
It is a longitudinal cross-sectional view of the coil winding device for winding an excitation coil and a detection coil around the outer periphery of the sensor part coil holder provided in the outer periphery of the steel wire rope.

FIG. 6 shows a wire rope disconnection detecting device according to the present invention.
It is a graph which shows the disconnection signal finally obtained.

FIG. 7 is a schematic vertical sectional view showing a conventional wire rope disconnection detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor part coil holder 2 Steel wire rope 3 Exciting coil 4 Exciting coil 5 Detecting coil 6a Leakage magnetic flux 7 Exciting circuit part 8 Phase detection circuit part 10 Sine wave oscillator 13 Phase shifter 14 Sensor 16 Phase detection circuit 17 Low pass filter 19 Abnormal display lamp (Abnormality display means) 21 Buzzer (alarm means) 22 Coil winding device 25 Vertical axis (axis) 27 Winding coil holder 28 Coil 29 Hollow cylindrical shaft 31 Winding coil holder I0 AC current VW Carrier signal VF Phase detection signal VC detection Signal VL 'disconnection detection signal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidetoshi Takimoto 3-1-1, Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toji Technical Center (72) Inventor Koichiro Nagata Toyosu 3-chome, Koto-ku, Tokyo No. 1-15 Ishikawajima Harima Heavy Industries, Ltd. Toji Technical Center F term (reference) 3F027 DA22 EA09 FA01

Claims (2)

[Claims] 1. A sensor unit comprising: a sensor; and a signal processing circuit having an excitation circuit unit and a phase detection circuit unit. The sensor includes a sensor unit coil holder provided on the outer periphery of the steel wire rope so as to be relatively movable with respect to the steel wire rope. A pair of serially connected exciting coils provided to be wound around the outer periphery of the sensor unit coil holder in the axial direction of the sensor unit coil holder, and on the outer periphery of the sensor unit coil holder so as to be located between the front and rear exciting coils. A detection coil wound so as to be able to detect a leakage magnetic flux of the steel wire rope, an excitation circuit unit of the signal processing circuit, a sine wave generator for applying an alternating current to the excitation coil, and the excitation coil A phase shifter connected in parallel and capable of changing a phase of an alternating current from the sine wave oscillator; Phase detector circuit portion of the circuit includes a phase detection circuit for obtaining a phase detection signal by multiplying the carrier signal from the detection signal and the phase shifter from the detection coil,
A low-pass filter that cuts off high-frequency components from the phase detection signal from the phase detection circuit and outputs a low-frequency component signal as a disconnection detection signal; and an alarm that issues an alarm when a disconnection detection signal is output from the low-pass filter. A wire rope disconnection detection device, comprising at least one of the means or an abnormality display means for performing an abnormality display. 2. A coil winding device comprising: a rotatable shaft; and a drivable hollow cylindrical shaft disposed parallel to the shaft and through which a steel wire rope can be inserted. At one end of the shaft, a winding coil holder in which coils are separately wound at three locations in the axial direction is detachably provided, and one end of the hollow cylindrical shaft is divided into a plurality of pieces in the circumferential direction. A coil detachably provided at one end of a hollow cylindrical shaft so as to surround a steel wire rope and unwound from the winding coil holder can be used as an exciting coil and a detecting coil at three axial positions. The wire rope disconnection detecting device according to claim 1, further comprising a winding coil holder that can be wound separately.