Current measuring device

Abstract

A current measuring device is provided that allows for easy characteristic testing of conductors (shunt resistors). [Solution] The current measuring device includes a cover member that integrally fixes the conductor and the current detection circuit. A portion of the conductor is exposed from the cover member on the opposite side of where the current detection circuit is located.

Description

Technical Field

[0001] The present invention relates to a current measuring device.

Background Art

[0002] There is a shunt resistor for measuring the magnitude of a current by flowing the current through a resistor and measuring the voltage (potential difference) across both ends thereof. Such a shunt resistor includes a resistor body and two electrodes connected to both ends of the resistor body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 2 discloses a current measuring device including a shunt resistor. Such a current measuring device includes a shunt resistor and a circuit board that processes a signal taken out from the shunt resistor. The periphery of the circuit board, including the periphery of the resistor body of the shunt resistor, is enclosed in a case or sealed by resin molding.

[0005] Generally, a current measuring device is assembled such that the resistance value of the shunt resistor becomes a desired resistance value. On the other hand, when assembling the current measuring device, the resistance value may change due to causes such as dimensional errors of the shunt resistor.

[0006] However, sealing the entire shunt resistor and circuit board makes it difficult to perform characteristic testing of the shunt resistor after assembling the current measuring device. On the other hand, there is a demand for an easier way to perform characteristic testing of shunt resistors.

[0007] Therefore, the present invention aims to provide a current measuring device that can easily perform characteristic testing of conductors (shunt resistors). [Means for solving the problem]

[0008] In one embodiment, a current measuring device for measuring electric current is provided. The current measuring device comprises a conductor through which the electric current flows, a current detection circuit fixed to the conductor, and a cover member that integrally fixes the conductor and the current detection circuit, wherein a portion of the conductor is exposed from the cover member on the opposite side of where the current detection circuit is located.

[0009] In one embodiment, the conductor is provided with a voltage detection terminal for detecting a voltage generated in the conductor, and the voltage detection terminal is exposed from the cover member. In one embodiment, the current measuring device includes a control device on which the resistance value measured through a portion of the conductor exposed from the cover member is written. In one embodiment, the current measuring device includes a temperature sensor positioned on a portion of the conductor exposed from the cover member. [Effects of the Invention]

[0010] The cover member has a structure that exposes a portion of the shunt resistor as a conductor. Therefore, the operator can easily perform characteristic testing of the shunt resistor through the portion of the shunt resistor exposed from the cover member. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows one embodiment of a current measuring device. [Figure 2]It is a diagram showing a current measurement device when the first detection circuit board is removed. [Figure 3] It is a diagram showing an embodiment of a conductor. [Figure 4] It is a side view of the current measurement device. [Figure 5] It is a top view of the second detection circuit board on the shunt resistor. [Figure 6] It is a top view of the first detection circuit board on the shunt resistor. [Figure 7] It is a diagram showing the circuit block of the current measurement device. [Figure 8] It is a diagram showing the current measurement flow by the control device. [Figure 9] It is a diagram showing another embodiment of the current measurement device. [Figure 10] It is a diagram showing another embodiment of the exterior structure. [Figure 11] It is a diagram showing another embodiment of the exterior structure. [Figure 12] It is a diagram showing another embodiment of the exterior structure. [Figure 13] It is a diagram showing a state where a probe is connected to the voltage detection terminal of the shunt resistor exposed from the exterior. [Figure 14] It is a diagram showing another embodiment of the exterior structure. [Figure 15] It is a diagram showing another embodiment of the current measurement device. [Figure 16] It is a diagram showing another embodiment of the current measurement device.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals, and redundant descriptions are omitted. In the following plurality of embodiments, the configuration of one embodiment not particularly described is the same as that of other embodiments, so the redundant descriptions thereof are omitted.

[0013] FIG. 1 is a diagram showing an embodiment of a current measurement device. As shown in FIG. 1, a current measurement device CMD is a device for measuring current. The current measurement device CMD includes a conductor (in this embodiment, a shunt resistor) SR through which current flows, a current detection circuit CS fixed to the shunt resistor SR, and an exterior (cover member) EC that houses the current detection circuit CS. The current detection circuit CS includes a plurality of substrates (in this embodiment, a first detection circuit substrate CS1 and a second detection circuit substrate CS2).

[0014] As shown in FIG. 1, the first detection circuit substrate CS1 and the second detection circuit substrate CS2 protrude from the region in the width direction of the shunt resistor SR. More specifically, the width W2 of the first detection circuit substrate CS1 and the second detection circuit substrate CS2 is wider than the width W1 of the shunt resistor SR. The exterior EC that houses the first detection circuit substrate CS1 and the second detection circuit substrate CS2 also protrudes from the region in the width direction of the shunt resistor SR (see the dotted line in FIG. 1).

[0015] FIG. 2 is a diagram showing the current measurement device when the first detection circuit substrate is removed. As shown in FIGS. 1 and 2, the first detection circuit substrate CS1 and the second detection circuit substrate CS2 are arranged hierarchically along the vertical direction. The first detection circuit substrate CS1 is arranged farther away from the shunt resistor SR than the second detection circuit substrate CS2. In other words, the second detection circuit substrate CS2 is arranged closer to the shunt resistor SR than the first detection circuit substrate CS1.

[0016] According to this embodiment, by forming a gap between the first detection circuit substrate CS1 and the shunt resistor SR, the first detection circuit substrate CS1 is arranged with an air layer interposed between it and the shunt resistor SR. Therefore, the first detection circuit substrate CS1 can be thermally isolated from the shunt resistor SR, and heat conduction from the shunt resistor SR can be suppressed. As a result, the current measurement device CMD can eliminate the influence of heat and can mount a plurality of devices.

[0017] Figure 3 shows one embodiment of a conductor. A shunt resistor SR, an example of a conductor, comprises a resistor 11 made of a resistance alloy plate material and a pair of electrodes 12 and 13 made of a highly conductive metal connected to both ends of the resistor 11. The electrodes 12 and 13 have the same structure and are arranged symmetrically with respect to the resistor 11.

[0018] Each end of the resistor 11 is joined to the electrodes 12 and 13 by means of welding (e.g., electron beam welding, laser beam welding, or brazing). Examples of materials for the resistor 11 include low-resistance alloys such as Cu-Mn alloys, Cu-Ni alloys, Ni-Cr alloys, and Fe-Cr alloys. An example of a material for the electrodes 12 and 13 is copper (Cu).

[0019] The shunt resistor SR is equipped with a pair of voltage detection terminals 14 and 15 positioned at predetermined locations on electrodes 12 and 13. Each of the voltage detection terminals 14 and 15 is a conductive pin extending perpendicularly from the respective surfaces of electrodes 12 and 13. By detecting the voltage between the voltage detection terminals 14 and 15, the current measuring device CMD can measure (calculate) the current flowing through the shunt resistor SR. Note that the conductor may be a busbar made of a single metal, such as copper, rather than the structure of the shunt resistor described above.

[0020] The current flowing through the shunt resistor SR generates a magnetic field around it. This magnetic field can affect (introduce noise to) the detection signal (especially analog signals) of the shunt resistor SR.

[0021] Therefore, in order to minimize the influence of such magnetic fields, a circuit for transmitting analog signals, which are relatively susceptible to magnetic field effects, is formed on the second detection circuit board CS2, which is close to the shunt resistor SR. A circuit for transmitting digital signals is formed on the first detection circuit board CS1, which is spaced away from the shunt resistor SR. The configurations of the first detection circuit board CS1 and the second detection circuit board CS2 will be described below.

[0022] Figure 4 is a side view of the current measuring device. Figure 5 is a top view of the second detection circuit board on the shunt resistor. Figure 6 is a top view of the first detection circuit board on the shunt resistor.

[0023] As shown in Figures 4 and 6, the first detection circuit board CS1 includes an isolation transformer 21 and an isolator 22, a control device 25, a connector 26, and a printed circuit board CB1 on which these electronic components (i.e., the isolation transformer 21 and isolator 22, the control device 25, and the connector 26) are mounted.

[0024] The control device 25 has a circuit parameter adjustment function and a temperature compensation function. These functions will be described later. The control device 25 consists of a microcomputer equipped with a processor and memory as a non-temporary storage medium, and is configured to calculate the current value (measured current value). The connector 26 is an output device for outputting the current value calculated by the control device 25 to an external device (not shown).

[0025] The isolation transformer 21 and the isolator 22 are configured to electrically isolate the first detection circuit board CS1 and the second detection circuit board CS2, and to supply power to the control device 25.

[0026] As shown in Figures 4 and 5, the second detection circuit board CS2 includes an analog front-end IC (hereinafter referred to as the AFE section) 51 for processing the analog signal from the shunt resistor SR, a temperature sensor 30 for measuring the temperature of the shunt resistor SR, and a printed circuit board CB2 on which these electronic components (i.e., the AFE section 51 and the temperature sensor 30) are mounted. Voltage detection terminals 14 and 15 extend through the printed circuit board CB2.

[0027] The first detection circuit board CS1 and the second detection circuit board CS2 are equipped with connectors 50A and 50B that are mechanically connected to each other. Therefore, the signal from the shunt resistor SR is transmitted from the second detection circuit board CS2 to the first detection circuit board CS1 through connectors 50A and 50B.

[0028] The first detection circuit board CS1 is equipped with a temperature sensor 40 for measuring the temperature of the AFE section 51 (particularly the amplification circuit 23 described later) or the ambient temperature. The temperature sensor 40 is located on the back side of the first detection circuit board CS1, i.e., above the AFE section 51 (see Figure 4). Therefore, the temperature sensor 40 can efficiently detect the temperature (more specifically, the temperature signal) of the AFE section 51.

[0029] Similarly, the temperature sensor 30 is located on the back side of the second detection circuit board CS2, i.e., above the shunt resistor SR (see Figure 4). Therefore, the temperature sensor 30 can efficiently detect the temperature (more specifically, the temperature signal) of the shunt resistor SR.

[0030] Figure 7 shows the circuit block of the current measuring device. As shown in Figure 7, the first detection circuit board CS1 includes a control device 25, a connector 26, and a temperature sensor 40, while the second detection circuit board CS2 includes an AFE section 51 and a temperature sensor 30. In Figure 7, the isolation transformer 21 and isolator 22 are not shown.

[0031] The AFE section 51 is a combination of an amplification circuit (i.e., an amplifier) ​​23 and an A / D converter 24a. In one embodiment, the amplification circuit 23 and the A / D converter 24a may be separate components. In the embodiment shown in Figure 1, the control device 25 and the A / D converter 24b are configured as a single unit, but in the embodiment shown in Figure 7, the control device 25 and the A / D converter 24b are separate components.

[0032] The A / D converter 24a and the control device 25 can communicate signals through connectors 50A and 50B. The voltage signals detected through the voltage detection terminals 14 and 15 of the shunt resistor SR are amplified by the amplification circuit 23 and converted into digital signals by the A / D converter 24a. The converted digital signals are input to the control device 25 through connectors 50A and 50B.

[0033] The temperature signal detected by the temperature sensor 30 for measuring the temperature of the shunt resistor SR is converted into a digital signal by the A / D converter 24a and input to the control device 25. The temperature signal may be amplified by the amplification circuit 23 if necessary.

[0034] Similarly, the temperature signal detected by the temperature sensor 40 for measuring the temperature of the amplification circuit 23 (or the ambient temperature around the amplification circuit 23) is converted into a digital signal by the A / D converter 24b and input to the control device 25.

[0035] The amplification circuit 23 has a temperature characteristic that causes the signal amplification factor to fluctuate depending on the temperature. Similarly, the shunt resistor SR has a temperature characteristic that causes the rate of change of its resistance to fluctuate depending on the temperature.

[0036] Therefore, the control device 25 is configured to correct the input voltage signal based on the signals detected by the temperature sensors 30 and 40, and to measure the current flowing through the shunt resistor SR. The current measurement flow by the control device 25 will be described later.

[0037] The control device 25 acquires the current circuit parameters (resistance value of shunt resistor SR, offset AD value described later, and amplification factor of amplifier circuit 23) based on the input information (i.e., signal) and predetermined temperature characteristic information. The temperature characteristic information is necessary for correcting the voltage signal and is stored in the memory (not shown) of the control device 25.

[0038] The control device 25 calculates the voltage value of the shunt resistor SR based on the current circuit parameters, and then calculates the current value (measured current value) from the calculated voltage value and the resistance value of the shunt resistor SR. Subsequently, the control device 25 outputs the calculated current value to an external device via the connector 26.

[0039] Figure 8 shows the current measurement flow by the control device. As shown in step S1, a voltage signal corresponding to the voltage generated across the shunt resistor SR (i.e., the voltage between voltage detection terminals 14 and 15) is acquired. The voltage signal is amplified by the amplification circuit 23 and converted into a digital signal (Vd1) by the A / D converter 24a. The converted digital signal is input to the control device 25.

[0040] As shown in step S2, when the temperature sensor 30 detects a temperature signal corresponding to the temperature of the shunt resistor SR, the control device 25 measures (acquires) the temperature (T1) of the shunt resistor SR from the temperature signal sent from the temperature sensor 30. More specifically, the temperature signal (thermistor voltage signal) detected by the temperature sensor 30 is amplified by the amplification circuit 23, converted into a digital signal by the A / D converter 24a, and sent to the control device 25.

[0041] As shown in step S3, when the temperature sensor 40 detects a temperature signal corresponding to the temperature of the current detection circuit CS (particularly the AFE section 51), the control device 25 measures (acquires) the temperature (T2) of the AFE section 51 from the temperature signal sent from the temperature sensor 40. More specifically, the temperature signal (thermistor voltage signal) detected by the temperature sensor 40 is amplified by the amplification circuit 23 (or an amplification circuit not shown) as needed, converted into a digital signal by the A / D converter 24b, and sent to the control device 25.

[0042] As shown in step S4, the control device 25 obtains the current offset AD value from the temperature T2 measured in step S3 and the temperature characteristics of the offset AD value stored in memory beforehand. Here, the offset AD value represents the difference in the signal output value according to the temperature of the shunt resistor SR. For example, when the temperature T2 is 25°C, the offset AD value is Vd25, and when the temperature T2 is 40°C, the offset AD value is Vd40. In this way, the offset AD value Vd is predetermined according to the temperature T2. The offset AD value (e.g., function, list) is stored in memory beforehand.

[0043] As shown in step S5, the control device 25 obtains the current amplification factor from the temperature T2 measured in step S3 and the temperature characteristics of the amplification factor of the amplification circuit 23 that are stored in memory beforehand. The amplification circuit 23 has temperature characteristics. Therefore, since the amplification factor changes depending on the temperature, the memory of the control device 25 stores the amplification factor according to the temperature.

[0044] As shown in step S6, the control device 25 obtains the current resistance value from the temperature T1 measured in step S2 and the temperature characteristics of the resistance value of the shunt resistor SR stored in memory beforehand.

[0045] As shown in step S7, the control device 25 calculates the current value. More specifically, first, the processor of the control device 25 calculates a corrected value by correcting the digital value Vd1 by subtracting the offset AD value obtained in step S4 from the digital value Vd1 obtained in step S1.

[0046] Next, the processor converts the correction value to a shunt output voltage value based on the amplification factor acquired in step S5, and calculates a voltage value from the shunt output voltage value by performing a predetermined conversion process. Subsequently, the processor calculates (measures) a current value from the calculated voltage value and the resistance value acquired in step S6. The calculated current value is output to an external device through the connector 26 (for example, a data bus).

[0047] Figure 9 shows another embodiment of the current measuring device. In the embodiment described above, the first detection circuit board CS1 is arranged with an air layer between it and the shunt resistor SR. In the embodiment shown in Figure 9, the current measuring device CMD has a resin layer formed between the first detection circuit board CS1 and the shunt resistor SR instead of forming an air layer.

[0048] As shown in Figure 9, the enclosure EC housing the current detection circuit CS includes an insulator IS positioned between the first detection circuit board CS1 and the shunt resistor SR. The insulator IS is, for example, a resin with dielectric strength.

[0049] The insulator IS can not only provide thermal insulation between the first detection circuit board CS1 and the second detection circuit board CS2, but also provide thermal insulation between the current detection circuit CS (more specifically, the first detection circuit board CS1 and the second detection circuit board CS2) and the shunt resistor SR.

[0050] In the embodiment shown in Figure 9, the insulator IS comprises an intermediate insulator ISa disposed between the first detection circuit board CS1 and the second detection circuit board CS2, an outer peripheral insulator ISb disposed outside the intermediate insulator ISa, and a wall-type insulator ISc on which the first detection circuit board CS1 and the second detection circuit board CS2 are placed. In one embodiment, the current measuring device CMD may include insulating paper (not shown) disposed between the first detection circuit board CS1 and the second detection circuit board CS2.

[0051] In this embodiment, the intermediate insulator ISa and the outer periphery insulator ISb are formed from the same resin material by insert molding. In one embodiment, the intermediate insulator ISa and the outer periphery insulator ISb may be formed from different resin materials.

[0052] The wall-type insulator ISc is positioned to ensure the distance between the first detection circuit board CS1 and the second detection circuit board CS2. More specifically, the wall-type insulator ISc has a stepped portion ISc-1 on which the first detection circuit board CS1 (printed circuit board CB1) is placed, and a bottom portion ISc-2 on which the second detection circuit board CS2 (printed circuit board CB2) is placed.

[0053] The stepped portion ISc-1 is located above the bottom portion ISc-2. Therefore, by placing the second detection circuit board CS2 (printed circuit board CB2) on the bottom portion ISc-2 and the first detection circuit board CS1 (printed circuit board CB1) on the stepped portion ISc-1, a certain distance is formed between the first detection circuit board CS1 (printed circuit board CB1) and the second detection circuit board CS2 (printed circuit board CB2).

[0054] The wall-type insulator ISc may be formed on the shunt resistor SR by insert molding, or a pre-formed wall-type insulator ISc may be attached to the shunt resistor SR. The wall-type insulator ISc may have an enclosure shape that supports the current detection circuit CS as a whole, or it may have a column shape that partially supports the current detection circuit CS.

[0055] As shown in Figure 9, the outer insulator ISb covers not only the circuit-side region of the shunt resistor SR (the region where the current detection circuit CS is located) but also the region on the opposite side of the circuit-side region (the opposite side region). Therefore, the voltage detection terminals 14 and 15 (and the resistor 11) are covered by the outer insulator ISb without being exposed.

[0056] With this configuration, the outer insulator ISb can prevent contact between the voltage detection terminals 14, 15 (and the resistor 11) and moisture. On the other hand, there is also a demand to perform characteristic testing of the shunt resistor SR after assembling the current measuring device CMD. To meet this demand, the outer casing EC may have a configuration that exposes a portion of the shunt resistor SR. An outer casing EC having such a configuration will be described below with reference to the drawings.

[0057] Figures 10 to 12 show other embodiments of the exterior structure. As shown in Figures 10 to 12, the exterior (i.e., cover member) EC that integrally fixes the shunt resistor SR and the current detection circuit CS has an exposed portion ECa formed in the region opposite to the circuit-side region where the current detection circuit CS is located (opposite region). In this embodiment, the exposed portion ECa is a notch that extends along the width direction of the shunt resistor SR.

[0058] A portion of the shunt resistor SR (in the embodiments shown in Figures 10 to 12, a portion of electrodes 12 and 13, the resistor 11 (around the junction between electrodes 12 and 13 and the resistor 11), and the voltage detection terminals 14 and 15) is exposed from the exposed portion ECa of the outer casing EC. In particular, the voltage detection terminals 14 and 15 penetrate electrodes 12 and 13 and extend to the opposite side of the outer casing EC. In this example, the voltage detection terminals 14 and 15 are described as single rod-shaped (pin-shaped) members that penetrate electrodes 12 and 13, respectively. However, voltage detection terminals of separate members may be formed on the upper and lower sides of electrodes 12 and 13, respectively. However, the structure shown in Figure 10, etc., is preferred because substantially the same signal can be obtained from both the upper and lower sides.

[0059] According to this embodiment, the operator can easily perform characteristic testing of the shunt resistor SR through a portion of the shunt resistor SR exposed from the outer casing EC.

[0060] Figure 13 shows a probe connected to the voltage detection terminal of a shunt resistor exposed from the casing. Generally, the current measuring device CMD is assembled so that the resistance value of the shunt resistor SR becomes the desired resistance value. However, during the assembly of the current measuring device CMD, the resistance value may change due to dimensional errors in the shunt resistor SR or other reasons.

[0061] Therefore, after assembling the current measuring device CMD, the probe PB is connected to the voltage detection terminals 14 and 15 of the shunt resistor SR to measure the resistance value of the shunt resistor SR. This measurement allows the operator to measure the resistance value more accurately, even if the resistance value of the shunt resistor SR changes during the assembly of the current measuring device CMD. In particular, by determining the connection position of the probe PB to the voltage detection terminals 14 and 15, variations in the resistance measurement position can be prevented. As a result, the operator can measure the resistance value with greater precision.

[0062] The operator may write the measured resistance value as a characteristic value to the memory of the control device 25. In other words, the current measuring device CMD is equipped with a control device 25 in which the resistance value measured through a part of the shunt resistor SR exposed from the outer casing EC (more specifically, the voltage detection terminals 14, 15) is written. With this configuration, the control device 25 can calculate the current value more accurately without being affected by the resistance value that changed during the assembly of the current measuring device CMD.

[0063] Figure 14 shows another embodiment of the exterior. As shown in Figure 14, the exterior EC may have an exposed portion ECb to expose only the voltage detection terminals 14 and 15. In the embodiment shown in Figure 14, the exposed portion ECb is an opening corresponding to the voltage detection terminals 14 and 15. Thus, the exterior EC may have a configuration that exposes at least the voltage detection terminals 14 and 15.

[0064] Figure 15 shows another embodiment of the current measuring device. As shown in Figure 15, the current measuring device CMD may include a temperature sensor 100 located on a portion of the shunt resistor SR exposed from the outer casing EC.

[0065] The temperature sensor 100 is electrically connected to the control device 25, which can measure the temperature of the shunt resistor SR based on the temperature signal detected by the temperature sensor 100. In other words, the current measuring device CMD includes a control device 25 to which the temperature signal detected by the temperature sensor 100 is input.

[0066] In one embodiment, for the purpose of verifying the performance of the current measuring device CMD itself, the operator may measure the resistance value of the shunt resistor SR using the probe PB and measure the temperature of the shunt resistor SR using the temperature sensor 100. The operator may also write these measurement results as characteristic values ​​to the memory of the control device 25.

[0067] Figure 16 shows another embodiment of the current measuring device. In the embodiment shown in Figure 16, the current measuring device CMD has a configuration that enhances the heat dissipation of the shunt resistor SR. More specifically, the current measuring device CMD includes a thermally conductive grease GR applied to the shunt resistor SR through the exposed portion ECa (or exposed portion ECb) of the outer casing EC, and a heat sink 110 connected to the exposed portion ECa (or exposed portion ECb).

[0068] In the embodiment shown in Figure 16, the current measuring device CMD includes both grease GR and heat sink 110, but it may also include at least one of grease GR and heat sink 110. With this configuration, the current measuring device CMD can dissipate heat from the shunt resistor SR.

[0069] In one embodiment, although not shown, the current measuring device CMD may be incorporated into a water cooling system within the junction box in which it is installed. This configuration also allows the current measuring device CMD to improve the heat dissipation of the shunt resistor SR.

[0070] According to the present invention, measurement accuracy in current measurement is improved, enabling accurate and highly precise current measurement. This is expected to improve energy efficiency, among other things. The present invention can contribute to Goal 3, "Ensure healthy lives and promote well-being," and Goal 12, "Responsible consumption and production," of the United Nations-led Sustainable Development Goals (SDGs).

[0071] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of symbols]

[0072] 11 Resistor 12,13 electrode 14,15 Voltage detection terminals 21 Isolation transformer 22 Isolators 23 Amplifier Circuit 24a, 24b A / D converter 25 Control device 26 connectors 30,40 Temperature Sensor 50A, 50B connectors 51 Analog Front-End IC (AFE section) 100 Temperature Sensor 110 Heatsink CMD Current Measuring Device SR shunt resistor (conductor) CS current detection circuit CS1 First Detection Circuit Board CS2 Second Detection Circuit Board EC exterior (cover material) ECa,ECb Exposed part W1, W2 width CB1, CB2 Printed Circuit Boards IS Insulator ISa Intermediate Insulator ISb outer insulator ISc Wall-type insulator ISc-1 Stepped section ISc-2 bottom PB probe GR Grease

Claims

1. A current measuring device for measuring electric current, The conductor through which the current flows, A current detection circuit fixed to the conductor, The system includes a cover member that integrally fixes the conductor and the current detection circuit, A current measuring device in which a portion of the conductor is exposed from the cover member on the opposite side of where the current detection circuit is located.

2. The conductor is equipped with a voltage detection terminal for detecting the voltage generated in the conductor. The current measuring device according to claim 1, wherein the voltage detection terminal is exposed from the cover member.

3. The current measuring device according to claim 1, further comprising a control device on which a resistance value measured through a portion of the conductor exposed from the cover member is written.

4. The current measuring device according to claim 1, further comprising a temperature sensor positioned on a portion of the conductor exposed from the cover member.

Images