JP2004361248A - Clamp type leakage current meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clamp type leakage current meter which is light and excellent in workability. <P>SOLUTION: A dividing section 18 is formed at the tip part of a clamp section 10, a part for housing a magnetic core 16 on the tip side is formed as a stationary-part case 11, and a part for housing a magnetic core 17 is formed as a movable-part case 12. Along with supporting the movable-part case 12 rotatably with respect to the stationary-part case 11 by providing a rotating shaft 15 on the opposite side of the base end part 14 of the stationary-part case 11 interposing the opening 13 of the dividing part, a crankshaft 25 is provided at a position separated from the rotating shaft 15 of the movable-part case 12 by a predetermined distance. A slidable slide knob 20 is provided on a sidewall of the base end part of the stationary-part case 11, a crank member 26 which engages the movable shaft 24 to the shaft fixing part 22 of the slide knob 20 and unites the movable shaft 24 to the crankshaft 25 is provided, and the movable-part case 12 is made freely-movable with respect to the stationary-part case 11 by sliding the slide knob 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a clamp-type leakage ammeter, and more particularly, is a handy type that is easy to carry, is lightweight and excellent in workability, and can be easily clamped even when a ground wire and a power line are close to each other. It is a devised one.
[0002]
[Prior art]
Conventionally, an Igr type probe has been used to search for an insulation failure point in a field such as a cubicle. Such an Igr type exploration device is for exploring the location of electric leakage by measuring the leakage current. As shown in FIG. 20, for example, a clamp current transformer (CT: current transformer) unit 01 for detecting electric current is provided. And a measuring device unit 02 that processes and displays a minute current, and is not easily portable. Note that the Igr type probe uses the Igr method for monitoring the effective current flowing in the ground insulation resistance from the leakage current generated by the insulation monitoring signal injected into the ground line, and the Igr for monitoring with the scalar amount of the vector sum of the currents. ₀ Insulation can be monitored with this method.
[0003]
In addition, a clamp-type leakage ammeter has been proposed that can measure a specific frequency current at a low frequency extremely easily and accurately, and is lightweight and excellent in workability. They are separated (see Patent Document 1).
Therefore, a clamp-type leakage ammeter with excellent portability has been conventionally demanded.
[0004]
On the other hand, in the conventional clamp-type leak current meter, when the ground line and the power line are close to each other, the clamp may not be clamped because it contacts the ground line or the power line when the clamp is opened.
[0005]
In other words, as shown in FIGS. 21A and 21B, conventional clamp parts are made movable parts 012A and 012B that halve the CT and fix one part as fixed parts 011A and 011B and rotate and open only the other part. In general, as shown in FIG. 22, the CT is halved and both are rotated and opened as a movable part 013. However, in the type that opens and closes in rotation, the opening / closing part of the clamp is at the tip and opens laterally, so that the ground wire or power line 020 cannot be clamped by the clamp 014 as shown in FIG. There is. Further, these push the lever 015 to open the movable parts 012A, 012B, 013 against a spring (not shown), and the spring is always biased in the closing direction while it is open.
[0006]
On the other hand, as shown in FIG. 24, there is a known type in which the clamp part is halved in the lateral direction, one is a fixed part 016 and the other is a movable part 017, and the slide lever 018 is slid in the direction of the apparatus body to open and close. (See Patent Document 2).
[0007]
[Patent Document 1]
Registered Utility Model No. 3046008
[Patent Document 2]
No. 7-54990
[0008]
[Problems to be solved by the invention]
In this slide type, since there is an open / close part in the lateral direction, even if the gap between the ground line and the power line is narrow, it can be clamped by rotating it after passing it upright, but the movable part 017 and the slide Since it is necessary to secure a space for the lever 018 to slide, there is a problem that the apparatus becomes large.
[0009]
In view of such circumstances, the present invention is a handy type that is easy to carry, is lightweight and excellent in workability, and can be easily clamped even when a grounding line and a power line are close to each other. It is an issue to provide.
[0010]
[Means for Solving the Problems]
A first aspect of the present invention that solves the above-mentioned problem is to divide and open the magnetic core and the case of a current transformer having a magnetic core and a case containing the magnetic core and having a window hole for passing a wire to be measured. A clamp-type leakage current meter comprising a flexible clamp unit and a measurement unit that processes a signal from the current transformer and measures a leakage current, and is inclined obliquely from the center of the tip of the clamp unit A portion for accommodating the magnetic core on the distal end side is provided as a fixed portion case, and the other movable magnetic core is accommodated and the portion movable with the magnetic core is a movable portion case. And a rotating shaft is provided on the outer side of the magnetic core on the opposite side across the window hole of the split portion at the base end portion of the fixed portion case so that the movable portion case can rotate with respect to the fixed portion case. To support In both cases, a crankshaft is provided at a position separated from the rotary shaft of the movable part case by a predetermined distance, and a slide knob that can slide from the front end side to the rear end side is provided on the side wall of the base end of the fixed part case. And a crank member that engages the movable shaft with an inner shaft fixing portion of the slide knob located on the rear end side of the rotation shaft and connects the movable shaft and the crank shaft. The clamp type leakage current meter is characterized in that the movable part case can be opened and closed with respect to the fixed part case by sliding.
[0011]
In the first aspect, the split part of the clamp part is provided obliquely from the tip side in an inclined direction so that the movable part case side can be rotated and the movable part case is opened and closed by a sliding knob and a crank mechanism. Therefore, the size of the opening in the open state can be kept large while saving space.
[0012]
According to a second aspect of the present invention, in the first aspect, there is provided a spring member that is elastically deformed when the movable part case opens and biases the movable part case in a closing direction. Clamp type leak current meter.
[0013]
In the second aspect, even when the movable part case is rotated in the opening direction, an elastic force that returns to the closing direction is applied by the spring member, and the closed state is easily maintained.
[0014]
According to a third aspect of the present invention, in the second aspect, when the movable part case is closed, the spring is fixed so as to be farthest from the movable shaft and approach the movable shaft as the movable part case rotates in the opening direction. A clamp type leakage current meter, wherein one end of the spring member is engaged with the spring fixing portion and the other end is engaged with the movable shaft. .
[0015]
In the third aspect, the spring member gradually elastically deforms as the movable part case rotates in the opening direction, and the elastic force acting in the rotation direction in the closing direction gradually increases.
[0016]
A fourth aspect of the present invention is the clamp type leak current meter according to the third aspect, wherein the spring fixing portion is a spring fixing shaft, and the spring member is a torsion coil spring.
[0017]
In the fourth aspect, the torsion coil spring gradually elastically deforms as the movable part case rotates in the opening direction, and the elastic force acting in the rotation direction in the closing direction gradually increases.
[0018]
According to a fifth aspect of the present invention, in the second or third aspect, the spring fixing portion is on or slightly beyond a straight line connecting the crankshaft and the movable shaft when the movable portion case is most open. The clamp type leakage current meter is characterized in that the movable part case is not urged in the closing direction by the spring member.
[0019]
In the fifth aspect, when the spring member is completely opened, the biasing force in the closing direction of the spring member does not act and the open state is maintained.
[0020]
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the rotating shaft, the crankshaft, and the movable shaft are positioned at the apex of a triangle when the movable portion case is closed. When opened, the crankshaft is located on a straight line connecting the rotating shaft and the movable shaft or slightly before this.
[0021]
In the sixth aspect, a crank mechanism for sufficiently securing the opening of the movable part case in an open state is realized while saving space.
[0022]
According to a seventh aspect of the present invention, in the sixth aspect, when the movable part case is closed, the crankshaft and the movable shaft are connected to the rear end of the base end part of the fixed part case from the rotating shaft. The clamp-type leakage ammeter is located on the side and in the region closer to the rotating shaft than the center of the window hole.
[0023]
In the seventh aspect, the crank mechanism for rotating the movable part case is provided in the region on the rear end side of the base end part of the fixed part case from the rotation axis and on the rotation axis side from the center of the window hole, thereby reducing the size. Can be planned.
[0024]
An eighth aspect of the present invention is the clamp type leakage current according to any one of the first to seventh aspects, wherein the divided portion is in the vicinity of a position inclined by 45 ° from the center of the tip portion of the clamp portion. In total.
[0025]
In the eighth aspect, since the divided portion is provided at a position inclined by about 45 ° from the center of the tip portion, the apparatus is in a standing state even if the measured wire is provided close to other wires. Clamping can be easily realized when inserting and clamping.
[0026]
According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the clamp portion and the measurement portion are integrated by being detachably engaged and the shape of the engagement portion is vertically and horizontally symmetrical. On the other hand, four contact points that are connected to opposite end surfaces of the engaging portion are arranged at symmetrical positions in the vertical and horizontal directions, and one pair of contact points at the symmetrical position of the engaging portion end surface of the clamp portion is provided. A clamp-type leakage current characterized by connecting a starting point and an ending point of the first winding of the magnetic core, respectively, and connecting a starting point and an ending point of the second winding of the magnetic core to the other pair of contacts, respectively. In total.
[0027]
In the ninth aspect, since the clamp part is detachable from the measurement part and can be joined even when it is rotated by 180 °, the operation direction for opening and closing the clamp part can be arranged at an easy-to-operate position.
[0028]
According to a tenth aspect of the present invention, in the ninth aspect, the four contacts on the end face of the engaging portion of the clamp portion are arranged in a straight line, and the first winding and the second wire are connected to the inner pair of contacts. A starting point and an end point of any one of the windings are connected, and a starting point and an end point of any one of the first winding and the second winding are connected to a pair of outer contacts. Clamp type leak current meter.
[0029]
In the tenth aspect, even if the clamp part is reversed and joined to the measurement part, it is not necessary to change the process in the measurement part.
[0030]
According to an eleventh aspect of the present invention, in the ninth or tenth aspect, the first engagement member that can be engaged with the engagement end portion of the clamp portion and the engagement end portion of the measurement portion can be engaged. The second engaging member, the contacts provided on the engaging portion end surfaces of the first engaging member and the second engaging member, and provided on the engaging portion end surface of the clamp portion, and the measuring portion. A clamp-type leakage current meter comprising a clamp part connecting member having a connection cable that connects contacts that are in contact with contacts provided on the end face of the engaging part.
[0031]
In the eleventh aspect, it can be used even in a state where the clamp part is separated from the measurement part according to the work situation, and the operability is improved.
[0032]
In a twelfth aspect of the present invention, in any one of the first to eleventh aspects, the measurement unit is provided with a reference signal input connector unit for Igr system, and a reference signal connected to the connector unit The acquisition code includes a pair of connection clips that are respectively connected to the ground phase and the ground portion, a pair of connection terminals that are connected to signal lines that are respectively connected to the connection clips, and a connector that is connected to the connector portion. A current-limiting resistor is attached to at least a connection clip connected to the ground phase of the pair of connection clips, and a voltage clip element for connecting the pair of connection terminals is attached to the connector. It is in the clamp type leak current meter characterized by being characterized.
[0033]
In the twelfth aspect, by using the reference signal acquisition code incorporating the current limiting resistor and the voltage clip element, the connector portion connected to the measurement unit can be remarkably reduced in size. System leakage current can be measured.
[0034]
A thirteenth aspect of the present invention is the clamp type leak current meter according to the twelfth aspect, wherein the voltage clip element is a Zener diode.
[0035]
In the thirteenth aspect, the withstand voltage of the connector can be improved at low cost by the Zener diode.
[0036]
A fourteenth aspect of the present invention is the clamp type leak current meter according to the twelfth or thirteenth aspect, wherein the voltage clip element comprises a plurality of Zener diodes connected in opposite directions.
[0037]
In the fourteenth aspect, even when an AC voltage is applied, a voltage higher than a predetermined voltage is not applied to the connector.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on an embodiment.
[0039]
FIG. 1 is a plan view and a side view of a clamp-type leakage ammeter according to an embodiment, FIGS. 2 to 4 are plan views with a part of the separated state cut away, FIG. 5 is a perspective view thereof, and FIG. FIG. 7 and FIG. 8 are enlarged plan views of the clamp part, FIG. 9 is a side view showing the separated state, and FIG. 10 is a plan view and a sectional view of the main part showing the separated state.
[0040]
As shown in these drawings, the clamp-type leakage ammeter includes a clamp unit 10 and a measurement unit 100, both of which are detachable.
[0041]
The clamp part 10 constitutes a ring-shaped part having a window hole 13 through which an electric wire to be measured is passed by a fixed magnetic core holding part 11 and a movable part case 12 constituting a part of a plastic fixed part case. The core holding part 11 and the movable part case 12 have a base end case 14 provided integrally with the fixed magnetic core holding part 11. The movable part case 12 is rotatable with respect to the fixed magnetic core holding part 11 and the movable part case 12 with respect to the fixed magnetic core holding part 11 and the movable part case 12 with respect to the fixed magnetic core holding part 11 and the base end case 14. Each of which includes a fixed magnetic core 16 and a movable magnetic core 17 each obtained by dividing a circular magnetic core into two parts.
[0042]
The division part 18 of the fixed magnetic core 16 and the movable magnetic core 17 is set at a position inclined by approximately 45 degrees with respect to the tip direction, and the rotary shaft 15 is located at a position opposite to the division part 18 through the window hole 13. Are provided outside the fixed magnetic core 16 and the movable magnetic core 17. The reason why the dividing portion 18 is inclined at about 45 ° in this manner is to facilitate clamping of the electric wire to be measured, as will be described later. In the present embodiment, the position of the rotary shaft 15 is set at 45 °, but the fixed magnetic core holding part 11 and the movable part case 12 are configured to overlap each other at the dividing part 18, so that the movable shaft case 15 is movable. When the part case 12 moves, the tip of the split part of the fixed magnetic core holding part 11 is inclined by (45 ° + θ; θ = 10-15 °) from the tip direction.
[0043]
Moreover, the structure of the fixed magnetic core 16 and the movable magnetic core 17 may be a conventionally well-known thing, and is not specifically limited. In the present embodiment, as shown in the side view of FIG. 6, the fixed magnetic core 16 and the movable magnetic core 17 have a laminated structure in which thin magnetic plates 19 such as permalloy are laminated. 16 and the thin plates 19 of the movable magnetic core 17 are alternately overlapped and joined. In addition, shield materials (not shown) are provided on the four sides of the laminated structure of the thin plates 19.
[0044]
Here, the base end case 14 is divided into two in the thickness direction, and is provided on the side wall on the one side (left side in the figure) in the width direction (left and right direction in the figure) of the divided part in the vertical direction in the figure. A slide knob 20 is slidably provided in the guide hole 14a. That is, the slide knob 20 has guide grooves provided on both sides in the thickness direction between the knob portion 21 that is protruded and held outside the base end case 14 and the shaft holding portion 22 that is protruded and held inside. 23 is slidably held by fitting with the opening edge of the guide hole 14a of the base end case 14.
[0045]
A movable shaft 24 is engaged with a through-hole penetrating in the thickness direction of the shaft holding portion 22 of the slide knob 20. On the other hand, it is separated from the rotating shaft 15 of the movable portion case 12 inward and downward (base end side). A crankshaft 25 is provided at this position, and the movable shaft 24 and the crankshaft 25 are connected by a crank 26. Here, when the slide knob 20 is located above (when the clamp is closed), the movable shaft 24 is located slightly below the left side of the rotary shaft 15 in the figure, and the vertical position of the crankshaft 25 is approximately in the middle between them. The rotary shaft 15, the movable shaft 24 and the crankshaft 25 are positioned to form a substantially isosceles triangle having the rotary shaft 15 as a vertex. Further, a spring fixing shaft 27 is provided at a position further inward and downward from the crankshaft 25 of the movable portion case 12 (positioned substantially rightward of the movable shaft 24 when the clamp is closed). A torsion coil spring 28 is provided between the shaft 27 and biased in a direction to separate them. The torsion coil springs 28 are provided on both sides in the thickness direction, and the movable shaft 24 is provided on both sides so as to sandwich the crank 26 (see FIG. 5).
[0046]
On the other hand, a lock member 30 is provided in the guide hole 14b on the side wall on the other side (right side) in the width direction (left and right direction in the figure) of the base end case 14 so as to be movable in the vertical direction. The stopper part 12a extended in the lower end in the figure of the movable part case 12 is located facing each other.
[0047]
This state will be described with reference to FIGS. 7 and 8 which are enlarged views. The lock member 30 includes an operation knob 31 protruding outward from the base end case 14 and a lock portion extending along the inner inner wall. 32 and an elastically deformable piece 33 provided in parallel to the inside of the lock portion 32, and a locking recess 34 is provided in the upper portion on the wall surface side of the lock portion 32, and the lock portion 32 moves upward. A locking projection 35 that engages with the locking recess 34 is provided on the inner wall of the base end case 14. As a result, when the operation knob 31 of the lock member 30 is moved upward by sliding upward, the tip of the lock portion 32 moves over the locking projection 35 to the locking position, and the locking recess 34 and The locking position is fixed by engaging the locking projection 35. At this position, the tip of the lock portion 32 and the stopper portion 12a come into contact with each other, and the rotation of the movable portion case 12 is restricted. When the operation knob 31 of the lock member 30 is pushed down and moved downward, the distal end portion of the lock portion 32 of the lock member 30 is separated from the wall surface and the engagement of the engagement recess 34 and the engagement projection 35 is released. Moves down to the unlock position. At this position, the lock portion 32 does not interfere with the stopper portion 12a, and the movable portion case 12 is allowed to rotate.
[0048]
In such a configuration, when the lock member 30 is moved to the unlock position and the slide knob 20 is slid downward, the movable part case 12 is pulled via the crank 26 and the crankshaft 25 engaged with the movable shaft 24. Rotate about the rotation axis 15. At this time, the spring fixing shaft 27 of the movable part case 12 moves in the direction approaching the movable shaft 24 against the elastic force of the torsion coil spring 28.
[0049]
By such rotation of the movable part case 12, an opening 18a is formed in the divided part 18, and the measured electric wire can be inserted into the window hole 13 through the opening 18a.
[0050]
As described above, in the present embodiment, the movable portion case is formed by the crank mechanism using the slide knob 20 and the crank 26 that slides downward while the movable portion case 12 is rotatable with the dividing portion 18 inclined obliquely from the front end side. Since 12 is opened and closed, the size of the opening 18a in the open state can be kept large while saving space. That is, the size of the opening 18a can be ensured larger than the movement amount of the slide knob 20. The positions of the rotary shaft 15, the movable shaft 24, and the crankshaft 25 that constitute the crank mechanism are arranged in a region below the rotary shaft 15 and on the left side of the center of the window hole 13, and rotate as described above when the clamp is closed. The shaft 15, the crankshaft 25 and the movable shaft 24 are arranged so as to form a triangle. When the clamp is opened, the crankshaft 25 is located near the intermediate position between the rotary shaft 15 and the movable shaft 24 and is almost a straight line. Since they are moved so as to be arranged in a letter shape, a sufficiently large opening 18a can be secured while saving space. It is sufficient that the opening 18a is slightly larger than the diameter of the window hole 13.
[0051]
In addition, although the stop position of the rotation of the movable part case 12 may be performed by regulating the slide position of the slide knob 20, in this embodiment, the stopper part 12a is a circular shape in the inner wall 14c of the base end case 14 or in the vicinity thereof. The position is regulated by contacting with a structure such as a boss (see FIG. 8).
[0052]
In the present embodiment, when the clamp is opened, the spring fixing shaft 27 is positioned between the movable shaft 24 and the crankshaft 25 so that the three members are arranged on a substantially straight line. At this time, in this embodiment, the crank 26 is provided with a recess 26a so that the spring fixed shaft 27 can move between the movable shaft 24 and the crankshaft 25. Is not necessarily required.
[0053]
As described above, in this embodiment, the crankshaft 25 moves in the opening direction while resisting the elastic force of the torsion coil spring 28 according to the rotation of the movable part case 12, that is, receiving the rotational force in the reverse direction (closing direction). The spring fixed shaft 27 is arranged on a substantially straight line with the movable shaft 24 and the crankshaft 25 when the crank is completely opened, so that the crankshaft 25 is given a rotational force in the closing direction. No state. Since this state is a delicately balanced state, if a rotational force in the closing direction is generated due to some impact or the weight of the movable part case 12 or the like, the balance is lost, and the movable part case is caused by the elastic force of the torsion coil spring 28. 12 is rotated in the closing direction.
[0054]
As described above, in this embodiment, even if the hand is released from the slide knob 20 when the clamp is opened, the open state is maintained without providing a special lock mechanism. This is because, as described above, the spring fixed shaft 27 is positioned between the movable shaft 24 and the crankshaft 25 when the crank is opened, and the three members are arranged on a substantially straight line. If the spring fixed shaft 27 is moved to a position slightly beyond the line connecting the movable shaft 24 and the crankshaft 25, the balance of the open state becomes more stable. In this case, the torsion coil spring 28 In order to make the elastic force work in the closing direction, it may be necessary to move the slide knob 20 in the closing direction.
[0055]
The above-described torsion coil spring 28 is provided in order to smoothly move the movable part case 12 from the open state to the closed state, but the type and arrangement position of the spring member are not limited thereto. Needless to say. Various spring members can be used as long as they are provided so as to act on other parts of the movable part case 12, and a leaf spring or the like can be used to provide and act similarly to the torsion coil spring 28. it can.
[0056]
The clamp unit 10 and the measurement unit 100 described above are detachable. That is, as shown mainly in FIGS. 9 and 10, an engaging convex portion 41 is formed at the lower portion of the clamp portion 10, and an engaging concave portion 42 is provided at the upper portion of the measuring portion 100. The engagement state is maintained by engaging a pair of locking projections 43 provided on both sides in the thickness direction of the central portion in the width direction of the clamp portion 10 with a locking groove 44 provided in the measurement unit 100. It is like that. The engagement state between the locking projection 43 and the locking groove 44 is released by a separation knob 45 provided integrally with the locking projection 43, and the locking projection 43 is moved by pushing the separation knob 45. The engagement state between the locking projection 43 and the locking groove 44 is released by elastic deformation.
[0057]
Here, four contact points 50 to 53 are provided on the joint surface of the engagement convex portion 41, and contacts 54 to 57 are provided on the joint surface of the engagement concave portion 42 at positions opposite to the contact points 50 to 53, respectively. Is provided. At the time of joining the clamp part 10 and the measuring part 100, it is preferable that either one of them is elastically deformed in the joining direction so that the contacts 50 to 53 and the contacts 54 to 57 come into contact with each other in a favorable conductive state. In this embodiment, the contacts 50 to 53 are in a planar state, and the contacts 54 to 57 are elastically deformed inward when pressed with a cross-sectional "<" shape.
[0058]
The contacts 50 to 53 are connected to the start point and the end point of the two types of windings of the magnetic cores 16 and 17. A schematic diagram showing this state is shown in FIG. As shown in the figure, the magnetic coils 16 and 17 include a first winding 58 and a second winding 59, and the inner contacts 51 and 52 are at the start and end points of the first winding 58. The outer contacts 50 and 53 are connected to the start and end points of the second winding 59. Of course, out of the contacts 54 to 57 corresponding to the contacts 50 to 53, the outer contacts 54 and 57 are connected to an element that inputs a signal from the second winding 59, and the inner contacts 55 and 56 are the first contacts. It is connected to an element for inputting a signal from one winding 58. Needless to say, the connection between the first winding 58 and the second winding 59 may be reversed.
[0059]
Here, the contacts 50 to 53 and the contacts 54 to 57 are provided in a straight line at the center of the joint surface, and the contacts 51 and 52 to which the start point and the end point of the first winding 58 are connected are mutually connected. The contacts 50 and 53 provided at the rotation reference position and connected to the start point and the end point of the second winding 59 are provided at rotationally symmetrical positions. Further, by making the shape of the joint convex part 41 and the joint concave part 42 vertically and horizontally symmetrical, the clamp part 10 can be joined by rotating 180 degrees. In other words, even if they are rotated and joined, the signals of the first winding 58 and the second winding 59 are input to the measuring unit 100 via the contacts 54 to 57 only at the connection positions at the start point and the end point. Therefore, the leakage current can be measured similarly. FIG. 12 shows a state in which the clamp unit 10 is joined to the measurement unit 100 by being rotated 180 ° in this way.
[0060]
As described above, if the clamp unit 10 can be joined even if the clamp unit 10 is rotated by 180 °, the position of the split unit 18 or the slide knob 20 of the clamp unit 10 is changed to the left or right side while viewing the operation unit 101 and the display unit 102 of the measurement unit 100. Since it can be arranged on the side, workability in a narrow place can be improved, and deterioration in operability due to differences in dominant arms can be improved.
[0061]
In addition, the arrangement of the contacts 50 to 53 and the contacts 54 to 57 for enabling the joining by rotating the clamp portion 10 is not limited to a straight line as described above, and corresponds to the first winding 58. And the contacts corresponding to the second winding 59 may be arranged at symmetrical positions in the vertical and horizontal directions. For example, the contacts may be provided in a row in the thickness direction, one pair is arranged in a row in the width direction, and the other pair is It may be arranged in a line in the thickness direction.
[0062]
On the other hand, the measurement unit 100 is provided with an operation unit 101 and a display unit 102 on one side, and a processing unit for processing signals from the contacts 54 to 57 is incorporated inside. The operation unit 101 performs mode switching, circuit voltage switching, range switching, and the like for switching the measurement target, and the display unit 102 displays necessary information such as mode and range and also displays measurement results. For example, it is formed by a liquid crystal panel or the like. Further, the processing unit only needs to detect a leakage current by a conventionally known process. ₀ Any method may be used as long as the leakage current is detected by the method, but the present embodiment also supports the Igr method. Therefore, when the leakage current is detected by the Igr method, a reference signal is required in addition to the signals from the contacts 54 to 57. For this reason, the connection connector portion 110 for connecting the reference signal acquisition cord is provided. ing. This point will be described later.
[0063]
The clamp type leakage ammeter of the present embodiment is provided with a clamp connection member so that it can be used even when the clamp unit 10 is separated from the measurement unit 100. As shown in FIG. 13 and FIG. 14, the clamp connection member 60 has a joint portion similar to the engagement concave portion 42 of the measurement unit 100 so that the clamp connection member 60 can be joined to the engagement convex portion 41 of the clamp portion 10. A joint member 61, a second engaging member 62 having a joint similar to the engaging convex portion 41 of the clamp portion 10 so as to be engageable with the engaging concave portion 42 of the measuring portion 100, and a connection for connecting them. And a cable 63. The first engagement member 61 incorporates contacts (not shown) connected to the contacts 50 to 53, and the second engagement member 62 includes contacts (not shown) connected to the contacts 54 to 57. Are built in, and these contacts are connected to each other via a connection cable 63. Needless to say, the second engaging member 62 is provided with a locking projection 43 and a separation knob 45 similar to those provided in the clamp portion 10.
[0064]
An example of the reference signal acquisition code connected to the connection connector unit 110 of the measurement unit 100 is shown in FIG. 15, and a schematic diagram is shown in FIG. As shown in these drawings, the reference signal acquisition code 120 includes a connector 121 connected to the connection connector portion 110, a connection clip 122 connected to the ground phase, and a connection clip 123 connected to the ground portion. The connector 121 and the connection clips 122 and 123 are connected by connection cords 124 and 125, respectively.
[0065]
The connector 121 includes at least a pair of connection terminals connected to the connection cords 124 and 125. As shown in FIG. 15B showing the disassembled state, the pair of connection terminals are connected to each other. A voltage clip element 126 is attached. The voltage clip element 126 acts so that a voltage higher than a predetermined voltage is not applied to the connector 121. In the present embodiment, a pair of zener diodes 126a and 126b (each corresponding to a 30V diode) connected in the opposite direction as the voltage clip element 126 are used, and an AC voltage of 30V or more is not applied to the connector 121.
[0066]
The voltage clip element 126 is not limited to this, and VRD (silicon surge absorber) can be used.
[0067]
On the other hand, the connection clips 122 and 123 are provided with an insulating cover 128 made of elastomer or rubber so as to cover the metal clip portion 127, and the connection clip 122 into which the current flows is shown in an exploded state in FIG. As shown in (c), a current limiting resistor 129 is incorporated. In this embodiment, 390 kΩ and 1 W resistors are used. The current limiting resistor 129 can limit the inflow of overcurrent when an erroneous connection is made. Similarly, a current limiting resistor may be provided in the clip portion 123 as well. Further, it is preferable to use an insulating connection clip having an insulating layer such as an insulating paint provided on the outside for the clip portion 127.
[0068]
By providing the voltage clip element 126 in the connector 121 and the current limiting resistor 129 in the connection clip 122 in this manner, the connector 121 can withstand a surge of several kV even if the size of the connector 121 is significantly reduced. Can do. That is, when the reference signal acquisition code 120 is normally connected, a voltage of several volts or more is not applied, but if it is accidentally connected to the charging phase instead of the ground phase, for example, 100 V or the like In consideration of the high voltage surge that will be applied between the connecting cords 124 and 125 and will be superimposed, a surge withstand voltage of several kV is required. Even in such a case, if the cord and the connector have a sufficient withstand voltage, the size becomes very large. However, by adopting the above-described structure, for example, the size of the connector 121 is a few minutes as the capacity. The size is one. Accordingly, the connection connector 110 provided in the measurement unit 100 can also be reduced in size.
[0069]
The clamp type leak current meter of the present embodiment described above is a handy type very small one, and since there is no installation type measuring instrument, since it can always be carried and measured as necessary, Very efficient work can be realized.
[0070]
Here, FIG. 17 shows a functional block diagram of the clamp type leak current meter of the present embodiment. As shown in FIG. 17, the function of the measuring unit 100 is I ₀ And a detection signal circuit 131 that detects Ig and an arithmetic / control circuit 132, a reference signal circuit 133, a power supply circuit 134, and a microprocessing unit (MPU) 135. The clamp unit 10 is connected to the detection signal circuit 131 and the calculation / control circuit 132 through a contact (not shown), and the reference signal circuit 133 acquires a reference signal through the connection connector unit 110 and the connector 121. Connecting clips 122 and 123 are connected. The MPU 135 is connected to a display unit 102 formed of an LCD, and further connected to various switches of the operation unit 101. In addition, various display lamps 103, an analog signal output circuit 104, and the like not described so far are connected. .
[0071]
I ₀ When the leakage current is detected by the method, a signal from the clamp unit 10 is detected by the detection signal circuit 131, and this detection signal is processed by the MPU 135 to detect the leakage current. This result is displayed on the display unit 102. Is displayed. On the other hand, in the case of the Igr method, the above-mentioned I ₀ Similar to the system, the reference signal is input to the MPU 135 to the reference signal circuit 133 via the connection clips 122 and 123. This signal is calculated by a signal from the MPU 135 in the calculation / control circuit 132 to control the clamp type CT. The signal thus detected is measured as Igr by the MPU 135, converted into an electric circuit voltage value, and displayed.
[0072]
In the clamp type leak current meter of the present embodiment, since the dividing portion 18 is provided at the inclined position as described above, there is an effect that the efficiency of the clamping work can be improved. That is, as explained in the section of the prior art, for example, if there is a divided portion at the center of the tip, the wire to be measured cannot be clamped, and it may be difficult to clamp even if it is inserted vertically. However, since the dividing portion 18 is provided in the vicinity of 45 ° obliquely and the opening 18a in a state where the movable portion case 12 is opened exists in a region obliquely forward from substantially the side, as shown in FIG. When there is another electric wire in the vicinity of the wire, the wire to be measured 200 can be easily passed through the window hole 13 by inserting it vertically with the clamp portion 10 in the open state and rotating it horizontally. it can.
[0073]
When the movable part case 12 is in the open state, the torsion coil spring 28 does not act in the closing direction, so that the above-described operation can be performed without pressing the slide knob 20 and the side wall is covered in the window hole 13. Since the movable part case 12 is rotated to the closed state by the action of the torsion coil spring 28 by applying some vibration after passing through the measuring wire 200, the operation can be performed very easily.
[0074]
Moreover, in this embodiment, since the clamp part 10 can be reversed and joined with respect to the measurement part 100 as above-mentioned, the position of the division part 18 or the position of the slide knob 20 is arrange | positioned in the direction where work is easy. The workability can be further improved.
[0075]
Furthermore, by using the clamp connecting member 60, only the clamp part 10 can be used apart from the measuring part 100, so that the clamp part can be further reduced in size, and clamping work in a space without space can be achieved. Furthermore, it can be performed efficiently.
[0076]
In addition, as described above, the reference signal acquisition cord 120 having the small connector 121 with high pressure resistance performance is attached and the connection connector portion 110 that can be connected to the small connector 121 is provided. Can measure the leakage current.
[0077]
An example of the state of leakage current measurement by the Igr method is shown in FIG. As shown in FIG. 19, the low voltage side of the transformer 201 and the load 202 are connected by an R phase 203, an S phase (ground phase) 204, and a T phase 205, and the ground phase 204 has a reference signal (leakage). A monitoring signal line 206 for flowing in a current monitoring signal) is connected, and the load 202 is grounded by a ground line 207.
[0078]
In order to detect the leakage current by the Igr method in such an environment, for example, the connection clip 122 of the reference signal acquisition cord 120 in which the connector 121 is connected to the connection connector unit 110 is connected to the S phase (ground phase) 204. A reference signal is acquired by connecting the connection clip 123 to the ground line 207, while leakage current is obtained by clamping the R phase 203, the S phase (ground phase) 204, and the T phase 205 with the clamp unit 10. Is detected. Further, by connecting the connection clip 122 to the monitoring signal line 206 and connecting the connection clip 123 to the ground 208, a reference signal is obtained. On the other hand, the monitoring signal line 206 is clamped by the clamp unit 10, thereby reducing leakage current. To detect.
[0079]
【The invention's effect】
As described above, according to the present invention, the movable portion case is opened and closed by the slide knob and the crank mechanism that are provided with the divided portion of the clamp portion in a direction obliquely inclined from the tip side so that the movable portion case side can be rotated. As a result, the size of the opening in the open state can be kept large while saving space, and it is a handy type that is easy to carry, is lightweight, and has excellent workability. Therefore, it is possible to provide a clamp-type leakage ammeter that can be easily clamped even if they are close to each other.
[Brief description of the drawings]
1A and 1B are a plan view and a side view of a clamp type leak current meter according to an embodiment of the present invention.
FIG. 2 is a plan view of a clamped leakage ammeter according to an embodiment of the present invention with a part of the separated state cut away.
FIG. 3 is a plan view of a clamp-type leakage ammeter according to an embodiment of the present invention with a part of the separated state cut away.
FIG. 4 is a plan view showing a state in which a part of the separated state of the clamp-type leakage ammeter according to the embodiment of the present invention is cut away.
FIG. 5 is a perspective view of a clamp unit according to an embodiment of the present invention.
FIG. 6 is an enlarged side view of a split portion of a clamp type leak current meter according to an embodiment of the present invention.
FIG. 7 is an enlarged plan view of a clamp portion according to an embodiment of the present invention.
FIG. 8 is an enlarged plan view of a clamp portion according to an embodiment of the present invention.
FIG. 9 is a side view showing a separated state of the clamp type leak current meter according to the embodiment of the present invention.
FIGS. 10A and 10B are a plan view and a cross-sectional view of a main part showing a separated state of a clamp type leak current meter according to an embodiment of the present invention.
FIG. 11 is a schematic diagram showing windings and contacts of a magnetic core according to an embodiment of the present invention.
FIG. 12 is a plan view showing a state in which a clamp part according to an embodiment of the present invention is rotated 180 ° and joined to a measurement part.
FIG. 13 is a plan view showing a state in which the clamp part and the measurement part of the present invention are connected by a clamp connecting member.
FIG. 14 is a plan view showing a state in which the clamp unit and the measurement unit of the present invention are connected by a clamp connection member.
FIGS. 15A and 15B are a plan view and a main part enlarged cross-sectional view of a reference signal acquisition code according to an embodiment of the present invention. FIGS.
FIG. 16 is a schematic diagram of a reference signal acquisition code according to an embodiment of the present invention.
FIG. 17 is a functional block diagram of a clamp type leak current meter according to an embodiment of the present invention.
FIG. 18 is a schematic view showing a usage state of a clamp-type leakage ammeter according to an embodiment of the present invention.
FIG. 19 is a schematic diagram showing a state of leakage current measurement by the Igr method according to an embodiment of the present invention.
FIG. 20 is a schematic view of a clamp-type leakage ammeter according to the prior art.
FIG. 21 is a schematic view of a clamp unit according to the prior art.
FIG. 22 is a schematic view of a clamp portion according to the prior art.
FIG. 23 is a schematic view showing a usage state of a clamp-type leakage ammeter according to the prior art.
FIG. 24 is a schematic view showing another example of a clamp portion according to the prior art.
[Explanation of symbols]
10 Clamp part
11 Fixed magnetic core holder
12 Movable part case
13 Window hole
14 Base end case
15 Rotating shaft
16 Fixed magnetic core
17 Movable magnetic core
18 division
20 Slide knob
24 movable shaft
25 Crankshaft
26 cranks
27 Spring fixed shaft
28 Torsion coil spring
30 Locking member
43 Locking projection
45 Separation knob
50-53, 54-57 contacts
58 First winding
59 Second winding
60 Clamp connection member
63 Connection cable
100 Measuring unit
110 Connector part
120 Reference signal acquisition code
126 Voltage clip element
129 Current limiting resistor

Claims (14)

The magnetic core of the current transformer having a magnetic core and a case incorporating the magnetic core and having a window hole for passing the wire to be measured, and a clamp part that can be opened and closed by dividing the case, and a signal from the current transformer A clamp-type leak current meter including a measurement unit that measures a leakage current by providing a split part of the magnetic core at a portion inclined obliquely from the center of the tip part of the clamp part. The part that stores the magnetic core on the side is a fixed part case, and the other movable magnetic core is stored and the part that moves together with the magnetic core is the movable part case, and the divided part at the base end of the fixed part case A rotating shaft is provided outside the magnetic core on the opposite side of the window hole so as to rotatably support the movable part case with respect to the fixed part case, and the rotational axis of the movable part case is A crankshaft is provided at a position spaced apart by a distance of the same, and a slide knob that is slidable from the front end side to the rear end side is provided on the side wall of the base end portion of the fixed case, and is positioned on the rear end side from the rotation shaft. A crank member is provided that engages the movable shaft with the inner shaft fixed portion of the slide knob and connects the movable shaft and the crankshaft. The slide knob slides the movable portion case to the fixed portion case. A clamp-type leakage ammeter characterized by being openable and closable. 2. The clamp type leak current meter according to claim 1, further comprising a spring member that is elastically deformed when the movable part case is opened and biases the movable part case in a closing direction. In Claim 2, when the movable part case is closed, the movable part case is provided with a spring fixing part that is most separated from the movable shaft and approaches the movable shaft as the movable part case rotates in the opening direction. A clamp type leak current meter, wherein one end of the spring member is engaged with the spring fixing portion and the other end is engaged with the movable shaft. 4. The clamp type leak current meter according to claim 3, wherein the spring fixing portion is a spring fixing shaft, and the spring member is a torsion coil spring. 4. The spring fixing portion according to claim 2, wherein the spring fixing portion moves to a position on or slightly beyond a straight line connecting the crankshaft and the movable shaft when the movable portion case is most opened. A clamp-type leakage ammeter, wherein the movable part case is not biased in the closing direction by the spring member. 6. The rotating shaft, the crankshaft, and the movable shaft according to claim 1, wherein the rotating shaft, the crankshaft, and the movable shaft are positioned at the vertices of a triangle when the movable portion case is closed, and the crankshaft is rotated when the movable case is opened. A clamp-type leakage ammeter characterized by being positioned on a straight line connecting a shaft and the movable shaft or slightly before this. 7. The crankshaft and the movable shaft according to claim 6, wherein when the movable portion case is closed, the crankshaft and the movable shaft are located on the rear end side of the base end portion of the fixed portion case from the rotation shaft and from the center of the window hole. A clamp-type leakage ammeter characterized by being located in a region on the rotating shaft side. The clamp type leak current meter according to claim 1, wherein the divided portion is in the vicinity of a position inclined by 45 ° from a center of a tip portion of the clamp portion. In any one of Claims 1-8, while making the said clamp part and the said measurement part detachably engage and integrating, while making the shape of an engaging part into an up-and-down left-right symmetrical shape, Four contact points connected to opposite end faces are arranged at symmetrical positions in the vertical and horizontal directions, and the first winding of the magnetic core is connected to one pair of contact points at symmetrical positions on the end face of the clamp part. A clamp-type leakage ammeter, wherein a start point and an end point are connected to each other, and a start point and an end point of the second winding of the magnetic core are connected to the other pair of contacts. In Claim 9, the four contact points of the engaging part end face of the clamp part are arranged in a straight line, and the starting point and the ending point of one of the first winding and the second winding are disposed on the inner pair of contacts. And a starting point and an ending point of any one of the first winding and the second winding are connected to a pair of outside contacts. In Claim 9 or 10, the 1st engagement member which can be engaged with the engagement end part of the above-mentioned clamp part, the 2nd engagement member which can be engaged with the engagement end part of the above-mentioned measurement part, and these A contact point provided on the engagement part end surface of the clamp part and a contact point provided on the engagement part end face of the clamp part and a contact point provided on the engagement part end face of the measurement part; A clamp-type leakage ammeter comprising a clamp part connecting member having a connection cable for connecting contact contacts. In any one of Claims 1-11, the said measurement part is provided with the reference signal input connector part for Igr systems, The reference signal acquisition code connected to this connector part is a ground phase, a ground part, and And a pair of connection terminals connected to the signal lines respectively connected to the connection clips and a connector connected to the connector portion, and the pair of connection clips A clamp type characterized in that a current limiting resistor is attached to at least a connection clip connected to the ground phase, and a voltage clip element for connecting the pair of connection terminals is attached to the connector. Leakage ammeter. The clamp-type leakage ammeter according to claim 12, wherein the voltage clip element is a Zener diode. 14. The clamp type leak current meter according to claim 12, wherein the voltage clip element is composed of a plurality of Zener diodes connected in opposite directions.

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