JP5497236B1 - Shunt for current measurement - Google Patents

Abstract

A shunt for current measurement capable of adjusting an electric resistance while checking a resistance value of a resistor in a state where an electric circuit at the time of measurement is reproduced.
A current measuring shunt 2 includes a first member 4 and a second member 40. The first member 4 and the second member 40 are in a measurement state in which current is measured. Then, the second member 40 is mounted on the same axis so as to cover the first member 4, and in the adjustment state in which the resistance value of the resistor 12 is adjusted, the second member 40 is opposite to the attachment in the measurement state. The member 40 is provided so that it can be attached to the first member 4 coaxially.
[Selection] Figure 1

Description

  The present invention relates to a current measuring shunt.

  Patent Document 1 discloses a first main circuit terminal serving as an input terminal, a second main circuit terminal serving as an output terminal, a resistor that is made in a cylindrical shape, and one end of which is electrically connected to the first main circuit terminal. A cylindrical current return conductor that is coaxially disposed outside the first end and is electrically connected to the second main circuit terminal and the other end is electrically connected to the other end of the resistor. Coaxial for current measurement composed of a measurement lead wire electrically connected and extending to the other end side of the resistor through the inside of the resistor and a measurement terminal electrically connected to the other end of the resistor Discloses shunts.

  Also, this coaxial shunt for current measurement is connected to the circuit so that the current to be measured flows to the first main circuit terminal, the resistor, the current return conductor and the second main circuit terminal, and the voltage across the resistor is measured. It is disclosed that a voltage is measured between a lead wire and a measurement terminal and a current is measured from the measured voltage.

  Here, in the current measurement using the shunt, the accuracy of the resistance value of the resistor affects the current measurement accuracy. For this reason, it is necessary to adjust the electrical resistance of the resistor so that there is no error between the actual resistance value of the resistor at the time of measurement and the resistance value used when calculating the current from the measured voltage.

JP 2003-315371 A

  In order to adjust the electrical resistance so that the actual resistance value of the resistor at the time of measurement becomes a predetermined resistance value, it is necessary to adjust after reflecting the influence of noise caused by the circuit configuration at the time of actual measurement. It is preferable to carry out while confirming the resistance value of the resistor in a state where the electric circuit at the time of measurement is reproduced.

  However, in the current measurement shunt described in Patent Document 1, in the state of use at the time of measurement, the resistor provided inside the shunt is covered with a cylindrical conductor, and each part is connected by brazing or welding. It has been configured. Therefore, it is difficult to adjust the electric resistance while confirming the resistance value of the resistor in a state where the electric circuit at the time of measurement is reproduced.

  An object of the present invention is to provide a current measurement shunt capable of adjusting an electric resistance while confirming a resistance value of a resistor in a state where an electric circuit at the time of measurement is reproduced.

  The present invention includes a first terminal portion through which a current to be measured flows, a first conductor portion electrically connected to the first terminal portion, and one end electrically connected to the first conductor portion. The measurement lead wire, the first conductor portion and one end electrically connected, a resistor provided in parallel with the measurement lead wire, the measurement lead wire penetrating, and the resistance A first member including a second conductor portion electrically connected to the other end of the body and a measurement terminal portion electrically connected to the second conductor portion, and a current to be measured flows. A second member having a second terminal portion and a third conductor portion electrically connected to the second terminal portion, wherein the second conductor portion is the second terminal. The first member and the second member are attached so as to be electrically connected to the third conductor portion at a position opposite to the side to which the portion is connected. The first member and the second member are configured to be coaxially attached so that the second member covers the first member in a measurement state where current is measured, and the resistor In an adjustment state in which the body resistance is adjusted, current measurement is provided so that the second member can be coaxially attached to the first member in the opposite direction to the attachment in the measurement state. For shunt.

  Preferably, the third conductor portion has an outer frame / conductor portion that covers the resistor along the resistor in the measurement state.

  Suitably, the said outer frame combined conductor part is provided with the clearance gap.

  Preferably, a plurality of the resistors are provided so as to surround the measurement lead wire in a circle.

  According to the present invention, there is provided a current measurement shunt capable of adjusting an electric resistance while checking a resistance value of a resistor in a state closer to an electric circuit at the time of measurement as compared with a case without this configuration. be able to.

It is a front view of the shunt 2 for current measurement which concerns on embodiment of this invention. It is a figure which shows the 1st member 4 which comprises the shunt 2 for electric current measurement which concerns on embodiment of this invention, (a) is a partial sectional view which shows the 1st member 4 from the front, (b) It is AA sectional view taken on the line in (a). It is a figure which shows the 2nd member 40 which comprises the shunt 2 for electric current measurement which concerns on embodiment of this invention, (a) is a front view of the 2nd member 40, (b) is the 2nd member 40. FIG. 4C is a perspective view of the second member 40. It is a schematic diagram explaining the attachment method of the 1st member 4 in the measurement state, and the 2nd member 40, (a) is a schematic diagram explaining the attachment direction, (b) is the current measurement after attachment. It is a schematic diagram which shows the shunt 2 for an object. It is a schematic diagram explaining the attachment method of the 1st member 4 in the adjustment state, and the 2nd member 40, (a) is a schematic diagram explaining the attachment direction, (b) is the electric current measurement after attachment. It is a schematic diagram which shows the shunt 2 for an object.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration of the current measurement shunt 2 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3. The current measuring shunt 2 according to the embodiment of the present invention includes a first member 4 and a second member 40, and the first member 4 and the second member 40 are attached to each other. ing. The first member 4 and the second member 40 are attached by a fastener 30.

  Here, as will be described later, the current measurement shunt is attached in a state where current measurement is performed (hereinafter referred to as a measurement state) and a state in which the resistance value of the resistor 12 described later is adjusted ( Hereinafter, the method of attachment in the adjustment state) is different, and the first member 4 and the second member 40 are provided so as to be attachable so as to realize both attachment methods. In addition, the attachment method shown in FIG.

  As shown in FIG. 2, the first member 4 includes a first terminal portion 6, a first conductor portion 8, a measurement lead wire 10, a resistor 12, and a second conductor portion 14. And a measurement terminal portion 16.

  The first terminal unit 6 is a terminal for inputting or outputting a current to be measured. In the present embodiment, the first terminal portion 6 is removably attached to the first conductor portion 8 by a fixing tool 7 such as a screw.

  The first conductor portion 8 is a conductor electrically connected to the first terminal portion 6. In this embodiment, the first conductor portion 8 is a cylindrical conductor portion from the bottom surface of the base conductor portion 18 that is a quadrangular columnar conductor portion. The terminal connecting conductor 20 is formed so as to extend. In the present embodiment, the first terminal portion 6 is attached by being wound around the terminal connecting conductor portion 20.

  The first conductor portion 8 includes a first insulator 22 provided on each side surface of the base conductor portion 18, and the base conductor portion 18 and the first terminal portion 6 on the side surface of the terminal connecting conductor portion 20. A cylindrical second insulator 24 is provided to cover the space between the two. In the present embodiment, the first insulator 22 is provided at a position facing the outer frame / conductor portion 48 in the mounting state in the measurement state.

  The measurement lead wire 10 is a lead wire led out from the first conductor portion 8 on one end side of the resistor 12 in order to measure the voltage in the voltage drop at the resistor 12, and the first conductor portion 8 is electrically connected. In the present embodiment, the measurement lead wire 10 is provided coaxially with the terminal connecting conductor portion 20 so as to extend from the first conductor portion 8.

  The resistor 12 is electrically connected to the first conductor portion 8 at one end and is provided in parallel with the measurement lead wire 10. In the present embodiment, a plurality of rod-shaped resistors 12 are provided on the same axis as the terminal connecting conductor portion 20 so as to surround the measurement lead wire 10 in a circular shape. In the example shown in FIG. 2, ten resistors 12 are provided along a circle centered on the measurement lead wire 10. By configuring the plurality of resistors 12 in this way, it is possible to reduce and measure the influence of noise caused by current flowing through the current measuring shunt 2 when measuring alternating current.

  The second conductor portion 14 is a conductor that is electrically connected to the other end of the resistor 12, and has a through hole 26 that allows the measurement lead wire 10 to pass therethrough. In the present embodiment, the second conductor portion 14 is formed in a rectangular column shape so as to have the same width as the base conductor portion 18 of the first conductor portion 8 including the width of the first insulator 22. Ten resistors 12 are electrically connected to the bottom surface. Further, in the present embodiment, a fastener receiving portion 28 is provided on each side surface of the second conductor portion 14, and a distal end portion of an outer frame / conductor portion 48 described later is provided on the fastener receiving portion 28. The process which receives a fastener so that it may attach to the side surface of the 2nd conductor part 14 with the fastener 30 is made | formed. The fastener is made of a conductor, for example, a screw. In the case of a screw, the fastener receiving portion 28 is processed with a female screw.

  In addition, although this embodiment demonstrates the structure which attaches the 1st member 4 and the 2nd member 40 with a fastener, the attachment method of the 1st member 4 and the 2nd member 40 attaches so that removal is possible. Any configuration may be used, and a fastener is not necessarily used.

  The measurement terminal portion 16 is a terminal electrically connected to the second conductor portion 14 in order to measure the voltage in the voltage drop at the resistor 12. In the present embodiment, the measurement terminal portion 16 further accommodates the measurement lead wire 10, and a voltage (not shown) connected to the voltmeter is attached to the measurement terminal portion 16, whereby the voltage at the resistor 12. The voltage at the drop is measured by a voltmeter.

  As shown in FIG. 3, the second member 40 includes a second terminal portion 42 and a third conductor portion 44.

  The second terminal portion 42 is a terminal for inputting or outputting current to be measured. In the present embodiment, the second terminal portion 42 is detachably attached to the third conductor portion 44 by a fixture 43 such as a screw.

  The third conductor portion 44 is a conductor that is electrically connected to the second terminal portion 42, and is formed in a shape that covers the first conductor portion 8 and the resistor 12 of the first member 4. In the present embodiment, the third conductor portion 44 includes a pedestal conductor portion 46 and an outer frame / conductor portion 48, and the pedestal conductor portion 46 and the outer frame / conductor portion 48 are fixed by a fixture 50. ing. The fixture 50 is made of a conductor, and is, for example, a screw. Note that the pedestal conductor 46 and the outer frame conductor 48 may be fixed by, for example, brazing or welding instead of the fixture 50.

  The pedestal conductor portion 46 has a shape in which a rectangular plate-like conductor is combined with the bottom of a cylindrical conductor, and the plate-like conductor is hollowed out according to the outer diameter of the terminal connecting conductor portion 20. . For example, in the present embodiment, the outer frame / conductor portion 48 is composed of four L-shaped flat plate conductors that are separated from each other by 90 degrees. The outer frame / conductor portion 48 is fixed to the four sides of the rectangular plate-like portion of the pedestal conductor portion 46 by a fixture 50. The outer frame / conductor portion 48 is disposed with a gap therebetween. Thus, in this embodiment, the 3rd conductor part 44 is provided with the clearance gap in the part which covers the resistor 12 in a measurement state. This gap contributes to heat dissipation in the resistor 12.

  The third conductor portion 44 covers at least a part of the first conductor portion 8 and the resistor 12 of the first member 4, so that the cylindrical inner diameter of the pedestal conductor portion 46 is the terminal connecting conductor portion 20. And the length between the opposing outer frame / conductor portions 48 in the space inside the four outer frame / conductor portions 48 is larger than the width of the first conductor portion 8. It is configured.

  In the present embodiment, a fastener receiving portion 52 is provided at the distal end portion of the outer frame combined conductor portion 48, and the distal end portion of the outer frame combined conductor portion 48 is connected to the second portion of the fastener receiving portion 52. The process which hold | maintains a fastener is made | formed so that it may attach to the side surface of the conductor part 14 with a fastener. When the fastener is a screw, a punch through the screw is processed.

  In this way, the second conductor portion 14 is electrically connected to the third conductor portion 44 at a position opposite to the side of the second conductor portion 14 to which the second terminal portion 42 is connected. In this embodiment, specifically, the front end of the outer frame / conductor portion 48 and the second conductor portion 14 are fixed.

  Next, how to attach the first member 4 and the second member 40 will be described. As shown in FIGS. 4 and 5, in the current measuring shunt 2, the direction in which the first member 4 and the second member 40 are attached is opposite between the measurement state and the adjustment state.

  Specifically, the first member 4 and the second member 40 are coaxially attached so that the second member 40 covers the first member 4 in the measurement state, and in the measurement state in the adjustment state. The second member 40 is configured to be attachable to the first member 4 coaxially in the direction opposite to the attachment of the first member 4.

  FIG. 4 is a schematic diagram for explaining how to attach the first member 4 and the second member 40 in the measurement state, and FIG. 4A is a schematic diagram for explaining the attachment direction. b) is a schematic diagram showing the current measuring shunt 2 after attachment.

  As shown in FIG. 4A, the terminal connection conductor portion 20 of the first member 4 passes through the inside of the cylinder of the pedestal conductor portion 46 of the second member 40 and is attached to the second state in the measurement state attachment method. The first member 4 and the second member 40 are attached so that the third conductor portion 44 of the member 40 covers the first conductor portion 8 and the resistor 12 of the first member 4. Then, as shown in FIG. 4B, the front end portion of the outer frame / conductor portion 48 is fixed to each side surface of the second conductor portion 14 by the fastener 30. In the present embodiment, when the measurement state is attached, if the first terminal portion 6 remains attached to the first conductor portion 8, the first terminal portion 6 interferes with the third conductor. Since the portion 44 cannot be attached, after the first terminal portion 6 is once removed from the first conductor portion 8, the first member 4 and the second member 40 are attached, and then the first terminal The part 6 is attached to the first conductor part 8.

  In the current measuring shunt 2 attached in this manner, the current to be measured includes the first terminal portion 6, the terminal connecting conductor portion 20, the base conductor portion 18, the resistor 12, the second conductor portion 14, and the outer frame. A voltage is applied to the measurement lead wire 10 and the measurement terminal portion 16 as a voltage across the resistor 12 so as to flow to the dual-purpose conductor portion 48, the pedestal conductor portion 46 and the second terminal portion 42. Thus, the current value of the current to be measured is measured. Here, at the time of measuring the alternating current, the direction of the current flowing through the resistor 12 and the direction of the current flowing through the outer frame / conductor portion 48 are opposite to each other, and noise due to induction from both currents is canceled out.

  Note that the current flow indicated by the arrows in FIG. 4B is an example, and may be used so as to flow in the direction opposite to the illustrated arrows. Further, the current to be measured is not limited to a direct current but may be an alternating current.

  FIG. 5 is a schematic diagram for explaining how to attach the first member 4 and the second member 40 in the adjusted state, and FIG. 5 (a) is a schematic diagram for explaining the attaching direction. b) is a schematic diagram showing the current measuring shunt 2 after attachment.

  In the adjustment state attachment method, unlike the attachment method shown in FIG. 4A, the second member 40 is inverted and attached to the first member 4 on the opposite side to the measurement state attachment. Then, as shown in FIG. 5B, the front end portion of the outer frame / conductor portion 48 is fixed to each side surface of the second conductor portion 14 by the fastener 30. At this time, the resistor 12 is not covered with the second member 40 and is in a released state. For this reason, it is possible to perform adjustment operations such as polishing on the resistor 12.

  The current measuring shunt 2 attached in this manner has a predetermined current value of the first terminal portion 6, the terminal connecting conductor portion 20, the base conductor portion 18, the resistor 12, and the second conductor. It is connected to the circuit so as to flow through the portion 14, the outer frame combined conductor portion 48, the pedestal conductor portion 46 and the second terminal portion 42. Note that the current flow indicated by the arrow in FIG. 5B is an example, and the current may flow in the direction opposite to the illustrated arrow.

  The adjustment of the resistance value of the resistor 12 is performed by measuring the voltage between the measurement lead wire 10 and the measurement terminal portion 16 in a state where a current having a predetermined current value is passed. This is performed by polishing the resistor 12 while confirming the above.

  Thus, according to the shunt 2 for current measurement, the electrical resistance can be adjusted while checking the resistance value of the resistor in a state closer to the electric circuit at the time of measurement as compared with the case where the present configuration is not provided. . Therefore, the accuracy of the actual resistance value of the resistor 12 in the current measuring shunt 2 in the measurement state can be improved.

2 Current measuring shunt 4 First member 6 First terminal portion 8 First conductor portion 10 Measuring lead wire 12 Resistor 14 Second conductor portion 16 Measuring terminal portion 40 Second member 42 Second member Terminal portion 44 Third conductor portion

Claims (4)

A first terminal portion through which a current to be measured flows;
A first conductor portion electrically connected to the first terminal portion;
A measurement lead wire having one end electrically connected to the first conductor portion;
A resistor which is electrically connected to the first conductor portion and one end and provided in parallel with the measurement lead;
A second conductor portion through which the measurement lead wire penetrates and electrically connected to the other end of the resistor;
A first member comprising: a measurement terminal portion electrically connected to the second conductor portion;
A second terminal portion through which the current to be measured flows;
A second member comprising: a third conductor portion electrically connected to the second terminal portion;
The second member is electrically connected to the third conductor at a position opposite to the side to which the second terminal is connected. It is a configuration to attach the member,
The first member and the second member are attached coaxially so that the second member covers the first member in a measurement state in which current is measured, and the resistance value of the resistor A shunt for current measurement is provided so that the second member can be coaxially attached to the first member in the opposite direction to the attachment in the measurement state in the adjustment state in which the adjustment is performed. The shunt for current measurement according to claim 1, wherein the third conductor portion includes a conductor portion serving as an outer frame that covers the resistor along the resistor in a measurement state. The shunt for current measurement according to claim 2, wherein the outer frame combined conductor portion is provided with a gap. The current measuring shunt according to claim 1, wherein a plurality of the resistive elements are provided so as to surround the measurement lead wire in a circle.

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