JP3046142U - Clamp meter inspection equipment - Google Patents

Abstract

(57) [Problem] To provide a small, lightweight and inexpensive clamp meter inspection device. SOLUTION: When a switch PB is pressed, a pulsating current is generated by a current from a battery E, and a coil 2 is generated as a pseudo AC current.
Is conducted. That is, the first pole S1 which is turned on
When a voltage is applied to the coil-side input terminal of the relay X via the relay, the contact S1 is turned off by this application, the applied voltage disappears, and the contact S1 is turned on again. The pulsating flow also flows through the coil 2 by the contacts of the relay X that repeats on / off operations. In this way, the pulsating flow is obtained by a small component called a relay, so that the device is particularly small and lightweight,
Easy carrying. By measuring the current of the coil 2 with a clamp meter and confirming the display, the clamp meter can be easily inspected anytime and anywhere.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a device for inspecting a clamp meter for measuring a current of an electric wire.

[0002]

[Prior art]

 In order to carry out electrical work safely, it is necessary to confirm that no current is flowing through the target wires, and a clamp meter is used for this confirmation. A clamp meter is a device that measures the electric current of an electric wire by using electromagnetic induction without directly touching the electric wire.

FIG. 6 is a diagram showing an example of a clamp meter. This clamp meter M is provided with semicircular sensor portions 12A and 12B at one end of a main body 11 also serving as a handle. The sensor section 12A is formed integrally with the main body 11. Further, the sensor portion 12B is formed integrally with the lever 13, is attached to the main body 11 by a rotating shaft (not shown), and is urged in a direction (clockwise in FIG. 6) in contact with the sensor portion 12A by the action of a spring (not shown). ing. Further, the main body 11 is provided with a circuit including a battery (not shown), a switch SW for turning on / off the power of the circuit, and a display unit 15 for displaying a current value calculated by the circuit. Have been.

In order to measure the electric current of an electric wire using the clamp meter M, as shown in FIG. 7, the sensor 13 is opened counterclockwise by pressing the lever 13 in the direction of arrow A1 (arrow A2). The electric wire W is inserted between the sensor unit 12A and the sensor unit 12B, and the sensor unit 12B is closed again. When the switch SW is turned on in this state, the sensor units 12A and 12B convert a change in a magnetic field generated by an alternating current passing through the electric wire into an induced current by a built-in coil. Then, the circuit built in the main body 11 calculates a current flowing through the electric wire based on the induced current, and displays the value on the display unit 15. After the measurement, the sensor unit 12B is opened again to release the electric wire, and the switch SW is turned off.

If such a clamp meter is used, it is not necessary to directly contact the measuring device with the electric wire or to cut a part of the circuit and connect the measuring device, so that the current can be measured safely and easily. . This clamp meter plays a particularly important role in ensuring safety when constructing large-capacity facilities. For example, in substation construction, when switching control cables, especially when disconnecting cables, it is necessary to always use a clamp meter and check that there is no current before disconnecting. If this check is not sufficient, the control cable of the live line (during current conduction) may be accidentally disconnected, causing a problem such as the occurrence of a mistrip accident.

[0006]

[Problems to be solved by the invention]

 As mentioned above, the main use of the clamp meter is to confirm that the electric current of the electric wire to be attached and detached in the electric work is zero by displaying the electric current. However, even if the display of the clamp meter is zero, only the display may be zero because the clamp meter has failed and no current is detected. For this reason, in order to ensure the safety of work with the clamp meter, it is necessary to confirm at any time by inspection that the clamp meter itself is normal. This is the same as, for example, checking the operation of the detector itself when checking the voltage of the main circuit with the voltage detector.

However, conventionally, there has been no apparatus for inspecting the clamp meter, and therefore, there is no other way to confirm the operation of the clamp meter except to actually measure the operating wires. Was. For this reason, the places and opportunities where the inspection of the clamp meter can be performed are limited, and a technology for easily and safely inspecting the clamp meter anytime and anywhere has been desired. Further, in order to inspect the clamp meter, it is necessary to generate an alternating current of 50 to 60 Hz, but such a circuit is complicated and expensive.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a small and lightweight portable clamp meter inspection apparatus. Another object of the present invention is to provide an inexpensive clamp meter inspection device.

[0009]

[Means for Solving the Problems]

 To achieve the above object, a clamp meter inspection device according to claim 1 is housed in a case, and a pulsating flow generating circuit for generating a pulsating current using a current from a battery; A switch for turning on / off a generating circuit, and a coil that conducts a pulsating flow generated by the pulsating flow generating circuit and that is at least partially located outside the case. . According to the first aspect of the present invention, by operating the switch, a pulsating current is generated by the current from the battery, and the current is conducted to the coil as a pseudo alternating current. By measuring the coil current with a clamp meter and checking the display, the clamp meter can be easily inspected anytime and anywhere.

According to a second aspect of the present invention, in the clamp meter inspection apparatus according to the first aspect, the pulsating flow generating circuit has a relay having a contact that is turned off by applying a voltage to the coil-side input terminal. The input terminal on the coil side is connected to the battery via the contact which is turned off, and the coil is connected to the battery via the contact of the relay. According to the invention of claim 2, when a voltage is applied to the coil-side input terminal via the contact that is on, the contact turns off by this application, the applied voltage disappears, and the contact turns on again. . In this way, the pulsating flow also flows through the coil due to the relay contacts that repeatedly turn on and off. As described above, since the pulsating flow is obtained by the small component called the relay, the device is particularly reduced in size and weight, and is easily carried.

According to a third aspect of the present invention, in the inspection apparatus for a clamp meter according to the second aspect, a capacitor for extending a cycle in which a contact of the relay repeats on and off is provided. According to the third aspect of the present invention, the cycle of the on / off operation can be adjusted to a desired one with a simple configuration of connecting a capacitor. In other words, if a capacitor with an appropriate capacitance is connected in parallel with the input terminal on the coil side of the relay, when the voltage applied to the input terminal on the coil side is generated or disappears, the capacitor will be charged and discharged, and Switching is delayed. For this reason, it is not necessary to adjust the cycle by a complicated circuit using a crystal oscillator or the like, and the device is small, light, and low in cost. Switches and contacts are protected by the action of a capacitor.

According to a fourth aspect of the present invention, in the inspection apparatus for a clamp meter according to the first aspect, a resistor for limiting a current flowing through the coil is provided. According to the fourth aspect of the present invention, the current flowing through the coil can be limited with a simple configuration in which a resistor is connected in series to the coil, so that the device is small, light, and low in cost. Switches and contacts are protected by the action of resistors.

[0013]

[Embodiment of the invention]

 Next, embodiments of the present invention will be specifically described with reference to the drawings. (1) Configuration of Embodiment First, FIG. 1 is a diagram showing an appearance of a clamp meter inspection device according to the present embodiment. As shown in this figure, the inspection device K of the present embodiment has a case 1, a push button switch PB provided in the case 1, and a coil 2 exposed in a loop outside the case. FIG. 2 is a conceptual diagram illustrating a state in which a front part of the case 1 is removed to show the inside. As shown in this figure, a battery 1 and a circuit board B are built in a case 1. The circuit board B, together with the battery E, the push button switch PB, the coil 2, and other wiring, constitutes a pulsating flow generating circuit (claim 1). The pulsating flow generating circuit is a circuit for generating a pulsating flow in which a DC current is intermittent while the push button switch PB is pressed, and for conducting the pulsating current to the coil 2 as a pseudo AC current. In the present application, “pulsating flow” is not limited to an alternating current as a common name, but means an intermittent direct current.However, it is required that a clamp meter can be inspected using a circuit that actually generates an alternating current. Is also good.

This pulsating flow generation circuit is an application of a relay X as shown in the circuit diagram of FIG. That is, the relay used in the present embodiment is a so-called A contact having two poles, and two sets (two poles) of contacts called a first pole and a second pole are connected while a voltage is applied to the coil-side input terminal. It will be turned on. Each contact has a common, which is one connection terminal of the contact, and an A terminal and a B terminal. In both electrodes, the common is conducted to the B terminal when no voltage is applied to the coil-side input terminal, and the common is applied when the voltage is applied. Is conducted to the A terminal. By connecting a circuit to the B terminal, both poles can be used as a so-called B contact that is turned off when a voltage is applied to the coil-side input terminal. The “coil-side input terminal” is an input terminal for controlling the relay, and simply referred to as “coil” means the coil 2 for conducting a pulsating flow.

As shown in FIG. 3, two circuits are connected in parallel to both poles of the battery E via a push button switch PB. The first circuit passes through the common terminal and the B terminal of the first pole S1 of the relay X, and passes through the coil-side input terminal of the relay X. The second circuit passes through the coil 2 via the common and the A terminal of the second pole S2 of the relay X. The coil 2 is formed by winding a vinyl wire about 10 times in a loop. As shown in FIG. 1, most of the coil 2 is exposed to the outside of the case 1. The exposed part is shaped into a substantially Ω shape and is protected by being gathered by a spiral resin cover 21. .

As shown in FIG. 3, an electrolytic capacitor C 2 is connected in parallel to the coil side input terminal of the relay X, and a resistor R for limiting the amount of current flowing is connected in series to the coil 2. ing. The electrolytic capacitor C and the resistor R also serve as a protection circuit for protecting switches from surge current.

(2) Functions and Effects of the Embodiment The present embodiment having the above configuration has the following functions. First, this inspection device has a simple configuration as described above, so it is small and lightweight, and can be configured to be about the size of a business card. In addition, since this inspection device operates only while the push button switch PB is pressed, it can be easily carried around while being stored in a pocket or the like at the time of electrical work.

Since the push button switch PB is off except during use, no voltage is applied to both the first and second circuits. At this time, the contacts S1 and S2 of the relay X are in the following state. That is, in the first pole S1 via the B terminal, the common is conductive to the B terminal, so that it is on. In addition, at the second pole S2 via the terminal A, the common is not conducted to the terminal A, so that the common is off.

When the clamp meter is to be inspected, first, as shown in FIG. 4, the switch SW of the clamp meter M is turned on, and the coil 2 of the inspection device K is located in the sensor units 12A and 12B. Let it. If the push button switch PB is not pressed in this state, no pulsating current is generated in the coil 2 of the inspection device K, and the display unit 15 of the clamp meter M indicates that the current is zero (FIG. 4). In this state, when the push button switch PB of the inspection device K is pushed down and turned on (FIG. 5), the following operation is performed.

First, when the push button switch PB is pressed, in the first circuit, a voltage is applied to the coil-side input terminal of the relay X and the electrolytic capacitor C via the first pole S1 which is already turned on. Applied. The applied voltage is primarily used for charging the electrolytic capacitor C at first, but when the capacity of the electrolytic capacitor C is satisfied, a sufficient voltage is applied to the input terminal on the coil side. As a result, the connection destination of the common in the first pole S1 is switched to the A terminal, and the first pole S1 via the B terminal is switched from on to off. As a result, the voltage applied to the coil-side input terminal of the relay X disappears after being instantaneously maintained by the discharge of the electrolytic capacitor C. When the voltage applied to the input terminal on the coil side disappears, the connection destination of the common at the first pole S1 is switched to the B terminal, so that the first pole S1 via the B terminal is turned on again, and the electrolytic capacitor C And the voltage application to the coil side input terminal is repeated again.

As described above, by connecting the coil-side input terminal of the relay X to the contact S1 controlled by the relay X itself, the contacts S1 and S2 of the relay X are turned on / off as described above. Will be repeated.

As a result of the relay X being repeatedly turned on and off in this way, the second pole S2 via the terminal A is repeatedly turned on and off in the opposite direction to the first pole S1, and the DC current is intermittently supplied to the coil 2. A pulsating flow is generated by flowing. This pulsating current plays the role of a pseudo AC current, and causes a change in the magnetic field around the coil 2 similarly to the AC current. Therefore, by measuring the pulsating flow flowing through the coil 2 with the clamp meter, it is possible to determine whether the clamp meter is normal or abnormal.

For example, when a battery E of 3 V (two dry batteries), an electrolytic capacitor C of about 470 μF and about 6.3 V, and a resistor of 2.2 Ω and 2 W type are used, the pulsating current is 0.2 A When the coil 2 is wound 10 times, a pulsating flow of about 2 A is obtained. If the clamp meter M is normal, a number close to the pulsating current, for example, 1.85 A is displayed on the display unit 15 (FIG. 5). Even if the push button switch PB of the inspection device K is pressed, if the display on the display unit 15 of the clamp meter M remains 0, it is clear that some abnormality exists in the clamp meter. In such a case, it is possible to take measures such as replacing or repairing the battery of the clamp meter, or re-inspecting and using another clamp meter, thus ensuring the safety of construction work.

As described above, according to the present embodiment, by operating the push button switch PB, a pulsating current is generated by the current from the battery E, and the pulsating current is conducted to the coil 2 as a pseudo AC current. You. By measuring the current of the coil 2 with the clamp meter M and checking the display, the clamp meter M can be easily inspected anytime and anywhere.

Further, in the present embodiment, when a voltage is applied to the coil-side input terminal via the first pole S1 which is turned on, the first pole S1 is turned off by this application, and the applied voltage is Disappears and the first pole S1 is turned on again. In this way, the pulsating flow also flows through the coil 2 by the second pole S2 of the relay X that repeats on / off. As described above, since the pulsating flow is obtained by the small component called the relay X, the inspection device K is particularly reduced in size and weight, and is easily carried.

In the present embodiment, the cycle of the on / off operation can be adjusted to a desired one with a simple configuration of connecting the electrolytic capacitor C. That is, since the electrolytic capacitor C having an appropriate capacity is connected in parallel with the coil-side input terminal of the relay X, when the voltage applied to the coil-side input terminal occurs or disappears, the electrolytic capacitor C is charged and discharged. Due to the discharge, the switching between the first pole S1 and the second pole S2, which are the contacts, is delayed. Further, by changing the combination of the voltage of the current supplied from the battery E and the capacity of the electrolytic capacitor C, a desired ON / OFF cycle can be obtained. For this reason, it is not necessary to adjust the cycle by a complicated circuit using a crystal oscillator or the like, and the inspection apparatus K is small, light, and low in cost. Further, the push button switch PB and the contacts S1 and S2 are protected from surge current by the action of the electrolytic capacitor C.

In the present embodiment, the current flowing through the coil 2 can be limited by a simple configuration in which the resistor R is connected in series to the coil 2, so that the inspection apparatus K is small and lightweight and low in cost. . Further, the action of the resistor R protects the push button switch PB and the contacts S1 and S2 from surge current.

(3) Other Embodiments The present invention is not limited to the above embodiments, but includes other embodiments as exemplified below. For example, specific elements such as the material and shape of the case constituting the inspection device, the type and model of the battery, the amount and cycle of the pulsating current, the shape and number of turns of the coil, the type of switch, and the mounting position are freely determined. Can be determined and changed. It is also free to place any part of the coil out of the case. For example, a cover that collectively protects the coils may be formed integrally with the case. In that case, a main part of the case containing the battery and the circuit board corresponds to the case described in claim 1. Further, the specific configuration of the pulsating flow generating circuit is free. For example, the push button switch PB may be provided on the side of the pole opposite to that in FIG. Alternatively, a relay having one contact (one pole) may be used, the coil-side input terminal may be connected to the B terminal, and the coil may be connected to the A terminal of the same contact. Further, since the on / off of the current to the coil and the coil-side input terminal does not need to be in the opposite phase, the coil and the coil-side input terminal may be connected to the same contact terminal. The specifications of the electrolytic capacitor and the resistor can be freely selected, and the type of the capacitor is not limited to the electrolytic capacitor, and another type of capacitor may be used.

[0029]

[Effect of the invention]

 As described above, according to the present invention, a small, lightweight and inexpensive clamp meter inspection device can be provided, so that the safety of electric work is greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of an inspection device for a clamp meter according to an embodiment of the present invention.

FIG. 2 is a diagram showing the inside of the inspection apparatus for the clamp meter according to the embodiment of the present invention.

FIG. 3 is a circuit diagram of a clamp meter inspection device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a state in which the clamp meter inspection device according to the embodiment of the present invention is combined with a clamp meter.

FIG. 5 is a diagram showing a state in which the inspection device for the clamp meter according to the embodiment of the present invention is combined with the clamp meter and a push button switch is pressed.

FIG. 6 is a diagram showing an appearance of a clamp meter.

FIG. 7 is a diagram showing a state in which a clamp meter is combined with an electric wire to be measured.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Case of clamp meter inspection device 2 ... Coil 21 ... Protective cover 11 ... Clamp meter main body 12 ... Sensor part 13 ... Lever 15 ... Display part B ... Circuit board C ... Electrolytic capacitor E ... Battery K ... Inspection of clamp meter Device M: Clamp meter PB: Push button switch R: Resistance S1: Contact (first pole) S2: Contact (second pole) SW: Switch X: Relay

Claims (4)

[Utility model registration claims] 1. A pulsating flow generating circuit housed in a case for generating a pulsating flow of current using a current from a battery; a switch for turning on / off the pulsating flow generating circuit; A coil that conducts a pulsating flow generated by the generating circuit and has at least a part positioned outside the case. 2. The pulsating flow generating circuit includes a relay having a contact that is turned off by applying a voltage to a coil-side input terminal, and the coil-side input terminal is connected to the battery via the contact that is turned off. The inspection device for a clamp meter according to claim 1, wherein the coil is connected to the battery via a contact point of the relay. 3. The inspection apparatus for a clamp meter according to claim 2, further comprising a capacitor for extending a cycle in which a contact of the relay repeats ON / OFF. 4. The inspection apparatus for a clamp meter according to claim 1, further comprising a resistor for limiting a current flowing through the coil.