JP2011027679A - Current detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: when fixing on a bottom plate of a distribution board, a conventional current detector needs to secure a space for attachment thereof, and a wiring attachment work thereof takes time and effort. <P>SOLUTION: A magnetic core 37 is arranged on an apparatus terminal metal fitting 26 of a breaker 21 for wiring, a conductor 32 is inserted into a through-hole 37b of the magnetic core 37, the conductor 32 is fastened between an apparatus terminal metal fitting 26 and a crimp terminal fitting 24 connected to the metal fitting 26 by using a terminal screw 25, the magnetic core 37 is therefore held between the apparatus terminal metal fitting 26 and the crimp terminal fitting 24. Thus, a current detector 31 is attached to the breaker 21 for wiring. In this condition, magnetic flux generates at the magnetic core 37 caused by a current flowing a current path that is formed by the conductor 32 and the terminal screw 25. By detecting the magnetic flux using a current sensor 33 at a gap 37a of the magnetic core 37, a current flowing between the apparatus terminal metal fitting 26 and the crimp terminal fitting 24 is detected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a current detector for equipment terminals having a core made of a magnetic alloy.

  Conventionally, as this type of current detector, for example, there is one used in a distribution board disclosed in Patent Document 1. In the distribution board, there is provided a circuit breaker 2 shown in the front view of FIG. 1 (a) and a partially broken side view of FIG. 1 (b). The current detector is a circuit breaker for wiring. It is comprised from the current transformer 1a with which the 2 load side electric wires 3 are mounted | worn. In the distribution board newly provided, the current transformer 1a is passed through the load side electric wire 3 before being connected to the circuit breaker 2 for wiring, and is fixed to the bottom plate of the distribution board by a fixing screw 4. In the existing distribution board, a split-type current transformer is attached to the load-side electric wire 3 after being connected to the circuit breaker 2 and fixed by the fixing screw 4. Or the load side electric wire 3 connected to the circuit breaker 2 for wiring is once removed, and the penetration type current transformer 1 a is passed through the load side electric wire 3 and fixed by the fixing screw 4.

  2A is a partially broken front view and FIG. 2B is a partially broken side view. In the watt hour meter 11a, through-type current transformers 1b and 1b are connected to a printed wiring board 12 to detect current. It is implemented as a container. The current lines 13 and 14 are passed through the current transformers 1b and 1b, respectively. Although not shown, a magnetic sensor is mounted on a printed wiring board as a current sensor, and a magnetic circuit formed of a U-shaped core is passed through and fixed to the current line, and the magnetic sensor is fixed to the U-shape of the core. There is also a configuration sandwiched between the end portions. Moreover, the watt hour meter 11b shown in the partially broken front view of FIG. 3A and the partially broken side view of FIG. 3B is formed through the terminal fittings 15 and 15 inside the watt hour meter 11b. The through holes of the current transformers 1c and 1c are inserted and attached.

JP 2001-103621 A

However, when the current transformer 1a shown in FIG. 1 is fixed to the bottom plate of the distribution board, it is necessary to secure a mounting space. In addition, it takes time to install and fix the load-side wire 3 with the fixing screw 4 through the current transformer 1a. In particular, when the width d ₁ of the crimp terminal 5 is greater than the inner diameter r of the through-hole of the current transformer 1a is crimp connected crimp terminals 5 to the load side wire 3 after inserting the load side wire 3 into the through-hole This requires additional labor for the installation and wiring work. In order to save this trouble, using the current transformer 1a inside diameter r is larger than the width d _1, amount that the inner diameter r increases, the current transformer 1a becomes large, and requires more core material , The cost will be higher.

In addition, when securing the current transformer 1a to the existing distribution board, if sufficient installation space cannot be secured on the bottom plate, the internal wiring of the distribution board is removed and each electric material is rearranged to reduce the installation space. It is necessary to secure. At that time, if the length of the load-side electric wire 3 is insufficient, it is necessary to remove the internal wiring of the distribution board and rearrange it or replace it with a longer load-side electric wire. Gets worse. Moreover, the use of current transformer 1a of segmented capable to put the load side wire 3 from the opening, when the width d ₁ of the crimp terminal 5 is greater than the inner diameter r of the through-hole of the current transformer 1a, Although the trouble of crimping and connecting the crimp terminal 5 to the load-side electric wire 3 after inserting the load-side electric wire 3 through the through-hole of the current transformer 1a can be saved, the split-type current transformer 1a is more than the through-type current transformer 1a. However, the price is high and the cost is higher than the case of using the through-type current transformer 1a.

  Further, in both the new distribution board and the existing distribution board, if the load-side electric wire 3 is thick and hard, the workability of the mounting work for attaching the current transformer 1a to the bottom plate of the distribution board is further deteriorated. To do. Moreover, when fixing the current transformer 1a to the load side electric wire 3 instead of the bottom plate of a distribution board, members for exclusive use for fixation, such as a binding band, are required.

Moreover, since the watt-hour meter 11a shown in FIG. 2 passes through the current line 14 through the current transformer 1b mounted on the printed wiring board 12, the total length of the current line 14 is increased and the cost of the wire material is high. Become. The end portion is bent in a circular shape machined terminal portion 13a of the current lines 13 and 14, the width _{d 2} of 14a, wider than the outer diameter _{d 3} of the current lines 13 and 14 from the need to enter into a terminal screw 16 And the inner diameter r of the through hole of the current transformer 1b needs to be large enough to allow the bent portions of the current lines 13 and 14, so that the current transformer 1b has a larger outer shape and the core material cost. Becomes higher. Further, the current line 14 may be deformed by the influence of vibration or impact when the current value is relatively small and the conductor length is long. For this reason, the fixing member for preventing the deformation | transformation of the electric current line 14 is needed, the attachment operation | work is needed and material cost also starts. Moreover, since the arrangement | positioning space | interval f of the terminal metal fittings 15 and 15 near the center of the current wire 13 is narrow, the current transformer 1b is used after the pitch between both ends of the current wire 13 is made wider than the pitch of the terminal metal fittings 15 and 15. It takes time to pass through the current line 13, and then adjust the pitch between both ends of the spread current line 13 to the pitch of the terminal fittings 15, 15.

Further, in the conventional watt-hour meter 11b shown in FIG. 3, the current transformers 1c and 1c are passed through the terminal fittings 15 and 15, respectively. It is necessary to increase the inner diameter r of the through hole of the vessel 1c. However, if the width of each terminal fitting 15 is reduced, a processing cost is required. Also, when the inner diameter r of the through hole of the current transformer 1c larger, outer shape core material cost increases to become larger, and increasing the size of the terminal block 18 due to the increase in terminal pitch d _4. Therefore, the mounting structure of each current transformer 1c shown in FIG. 3 is unsuitable except for the watt hour meter 11b having a relatively large and large capacity terminal.

The present invention has been made to solve such problems,
A core made of a magnetic alloy having a gap;
An insertion hole having an outer diameter inserted into the core through-hole and a height higher than the through-hole height of the core is formed, and disposed substantially concentrically with the through-hole. The conductive material is fastened between the device terminal and the connection terminal connected to the device terminal by a screw having a through-hole held between the device terminal and the connection terminal. A conductive conductor,
A current sensor for detecting a magnetic flux generated in the core arranged in the gap and detecting a current flowing in a current path formed by a conductor and a screw between the equipment terminal and the connection terminal. A current detector was constructed.

  According to this structure, a core is arrange | positioned on an apparatus terminal, a conductor is inserted in the through-hole of a core, and a conductor is fastened between an apparatus terminal and the connection terminal connected to this with a screw which has electroconductivity. Thus, the core is held between the equipment terminal and the connection terminal, and the current detector is attached to the electrical equipment. In this state, a magnetic flux is generated in the core by a current flowing through a current path formed by a conductor and a screw, and this magnetic flux is detected in the gap of the core by a current sensor, whereby a current flowing between the device terminal and the connection terminal is generated. Is detected.

  According to the present invention, the current detector can be attached by simply removing the wiring connected to the equipment terminal exposed to the outside of the electrical equipment, placing the core on the equipment terminal, and re-fastening the terminal screw. Workability is improved. In addition, when a current detector is attached to an existing electrical device, the current detector can be attached in the same manner, and the workability of the attachment work is improved. Further, since the conductor is fixed to the device terminal by a terminal screw and no bending stress is generated in the conductor, the strength of the conductor is increased and the conductor is extremely resistant to vibration and impact. In addition, since a dedicated member for fixing the current detector is not required, the cost can be kept low without increasing the number of parts. In addition, in the electrical equipment, it is not necessary to increase the overall length of the conductor such as the current line in order to penetrate the current detector as in the conventional case, and the conductor material cost can be reduced, and the insulation distance inside the electrical equipment can be reduced. Since there is a margin, the printed wiring board can be miniaturized.

(A) is a front view of the circuit breaker for wiring provided with the conventional electric current detector, (b) is the partially broken side view. (A) is the partially broken front view of the watt-hour meter provided with the conventional electric current detector, (b) is the partially broken side view. (A) is the partially broken front view of the other watt-hour meter provided with the conventional electric current detector, (b) is the partially broken side view. (A) is the front view of the circuit breaker for wiring which is not provided with the current detector, (b) is the partially broken side view. (A) is a front view of the circuit breaker for wiring provided with the current detector by one Embodiment of this invention, (b) is the partially broken side view. (A) is an exploded perspective view of the current detector provided in the circuit breaker shown in FIG. 5, (b) is a longitudinal sectional view thereof, and (c) is a perspective view showing a modification thereof. (A) is the partially broken front view of the watt-hour meter provided with the electric current detector shown in FIG. 6, (b) is the partially broken side view.

  Next, an embodiment for carrying out the present invention will be described.

  FIG. 4A is a front view of the circuit breaker 21 without a current detector, and FIG. 4B is a partially broken side view thereof.

  In the circuit breaker 21 for wiring, the power supply side electric wires 22a, 22b, 22c are connected to the power supply side terminal portion provided at the upper end portion, and the load side electric wires 23a, 23b, 23c are connected to the load side terminal portion provided at the lower end portion, When a current of a predetermined value or more flows through the load side electric wires 23a, 23b, 23c, the current is cut off. Crimp terminal fittings 24 are crimped and connected to the ends of these electric wires 22a, 22b, 22c, 23a, 23b, and 23c. Each crimping terminal fitting 24 is fastened to the equipment terminal fitting 26 by a terminal screw 25, and each electric wire 22a, 22b, 22c, 23a, 23b, 23c and each equipment terminal fitting 26 are connected.

  FIG. 5A is a front view showing a state in which the circuit breaker 21 shown in FIG. 4 includes the current detector 31 according to the present embodiment, and FIG. 5B is a partially broken side view thereof. In the figure, the same parts as those in FIG.

  The current detectors 31, 31 are respectively connected to the terminal screw 25, between the crimp terminal fittings 24, 24 of the load side electric wires 23 a, 23 c and the equipment terminal fittings 26, 26 at the load side terminal portion of the wiring breaker 21. 25 is fastened and provided. Each current detector 31 is shown in an exploded perspective view in FIG. 6A and a longitudinal sectional view in FIG.

  The current detector 31 includes a conductor 32, a current sensor 33, a magnetic core 37, and a case 38. The current sensor 33 is mounted on the printed wiring board 34 as a Hall element or the like, and a lead wire 36 is connected to the printed wiring board 34. A connection portion between the printed wiring board 34 and the lead wire 36 is supported while being protected by a lead wire support 35 formed of an elastic material.

  The magnetic core 37 is made of, for example, an alloy of iron and nickel (Fe—Ni) and made of a magnetic alloy such as permalloy having a high magnetic permeability, has a gap 37a, and a through hole 37b is formed at the center. The magnetic core 37 is accommodated in a space between the outer wall 38a and the inner wall 38b of the case 38 with the position of the gap 37a aligned with the slit 38c. In the gap 37a of the magnetic core 37, the printed wiring board 34 is inserted into the slit 38c and the lead wire support 35 is attached to the case 38, whereby the current sensor 33 is arranged. The assembly including the printed wiring board 34 on which the current sensor 33 is mounted, the lead wire support 35 and the lead wire 36 is cured by filling a case 38 containing the magnetic core 37 with an elastic resin or adhesive. Thus, the case 38 is fixed.

  The conductor 32 is made of a non-magnetic hollow cylindrical conductor having high conductivity, and a collar 32a is provided at the upper end of the cylindrical portion. The cylindrical portion is formed with an insertion hole 32b disposed substantially concentrically with the through hole 37b of the magnetic core 37, and is inserted into the space inside the inner wall 38b of the case 38. The conductor 32 has an outer diameter inserted into the through hole 37b of the magnetic core 37 and a height higher than the height of the magnetic core 37 in the through hole 37b direction, as shown in FIG. A groove 32c provided on the outer periphery is fitted to a protrusion 38d provided on the inner periphery of the inner wall 38b and fixed to the case 38. Due to this fitting, the case 38 and the magnetic core 37 are elastic so that stress acting on the conductor 32 acts on the magnetic core 37 via the case 38 and the characteristics of the magnetic core 37 do not change. The resin is filled in the case 38 as described above. The case 38 protects the current sensor 33 and the magnetic core 37 and has mechanical strength for fixing the conductor 32, and heat resistance against heat generated by the current flowing through the conductor 32, and is a resin material having high electrical insulation. It is molded from.

  As shown in FIG. 5, the conductor 32 has a terminal screw 25 having conductivity inserted in the insertion hole 32 b, and the height direction of the conductor 32 is a crimp terminal fitting 24 that is a device terminal fitting 26 and a connection terminal connected thereto. And the magnetic core 37 in which the through hole 37b is disposed substantially concentrically with the insertion hole 32b is held between the device terminal fitting 26 and the crimp terminal fitting 24. The conductor 32 and the terminal screw 25 held between the equipment terminal fitting 26 and the crimp terminal fitting 24 form a current path for current flowing from the circuit breaker 21 for wiring to the load side wires 23a and 23c. A magnetic flux is generated in the magnetic core 37 by the current flowing. The magnetic core 37 has a magnetic flux collecting function and supplies magnetic flux to the current sensor 33 disposed in the gap 37a. The current sensor 33 detects the current flowing through the current path by detecting the magnetic flux collected in the gap 37a.

  Power is supplied to the printed wiring board 34 from the host system via the lead wire 36. The magnetic flux detected by the current sensor 33 is converted into a voltage signal or a digital signal by a circuit formed on the printed wiring board 34 and transmitted to the host system via the lead wire 36. The host system processes the transmitted voltage signal or digital signal and displays the current value detected by the current sensors 31, 31 or shuts off another circuit according to the current value detected by the current sensors 31, 31. Control. When the distance to the host system is long, an amplifier circuit for amplifying a voltage signal or a digital signal transmitted to the host system is added to the printed wiring board 34 or the like. The lead wire 36 is a shield wire in an environment that is affected by electromagnetic waves.

  According to the present embodiment, the magnetic core 37 is arranged on the equipment terminal fitting 26 of the circuit breaker 21 for wiring, the conductor 32 is inserted into the through hole 37 b of the magnetic core 37, and the equipment terminal fitting 26 is connected with the terminal screw 25. By fastening the conductor 32 between the crimp terminal fitting 24 connected thereto, the magnetic core 37 is held between the device terminal fitting 26 and the crimp terminal fitting 24, and the current detector 31 is connected to the circuit breaker 21 for wiring. Attached to. In this state, a magnetic flux is generated in the magnetic core 37 by a current flowing through a current path formed by the conductor 32 and the terminal screw 25, and this magnetic flux is detected in the gap 37a of the magnetic core 37 by the current sensor 33. A current flowing between the equipment terminal fitting 26 and the crimp terminal fitting 24 is detected.

  For this reason, the load side electric wires 23a and 23c connected to the equipment terminal fittings 26 and 26 exposed to the outside of the circuit breaker 21 for wiring are removed, and the magnetic cores 37 and 37 are arranged on the equipment terminal fittings 26 and 26, and the terminals The current detectors 31 and 31 can be attached simply by re-fastening the screws 25 and 25, thereby improving workability. Further, when the current detector 31 is attached to the existing circuit breaker 21, the current detectors 31 and 31 can be attached in the same manner. Therefore, unlike the conventional case, it is not necessary to rearrange the internal wiring of the distribution board, and the workability of the mounting work is improved. In addition, since the current detectors 31 and 31 can be installed under the existing wiring of the distribution board and the shape and length of the internal wiring are not affected, there is no need to change the existing wiring.

  Further, it is not necessary to secure a space for installing the current detector 31 in the distribution board or the like as in the prior art. Further, since the current detector 31 is passed through the load side electric wires 23a and 23c and the work for fixing to the bottom plate of the distribution board with the screws 4 as in the conventional circuit breaker 2 shown in FIG. Eliminates the hassle of wiring work. In particular, even when the width of the crimp terminal fitting 24 is larger than the inner diameter of the through hole of the current detector 31, after the load side electric wires 23a and 23c are inserted into the through hole, the crimp terminal fittings 24 and 24 are connected to the load side electric wire 23a, Since there is no need to connect to 23c, the installation wiring work is not time-consuming. Further, in order to save this trouble, it is not necessary to use a current detector in which the inner diameter of the through hole is larger than the width of the crimp terminal fitting 24, and the cost does not increase. In addition, since it is not necessary to use a split-type current detector that is more expensive than the through-type current detector 31, costs can be reduced. Moreover, since the load side electric wires 23a and 23c are not moved, even if the load side electric wires 23a and 23c are thick and hard, the workability of the mounting work of the current detectors 31 and 31 is not deteriorated. Further, it is not necessary to separately use a dedicated mounting member for attaching the current detectors 31 and 31 to the wiring breaker 21, and the current detector 4 is connected to the load-side electric wire as in the conventional wiring breaker 2 shown in FIG. No special member for fixing for fixing to 3 is required. For this reason, the current detector 31 can be attached to the circuit breaker 21 without increasing the number of parts and keeping the cost low.

  In the above embodiment, the case where the magnetic core 37, the printed wiring board 34, and the lead wire 36 are fixed to the case 38 by the lead wire support 35 has been described. However, the present invention is not limited to this configuration. For example, as shown in FIG. 6 (c), a resin 39 which is filled with a heated and melted resin, and a printed wiring board 34 and a lead wire 36 on which a magnetic core 37 and a current sensor 33 are mounted is indicated by a one-dot chain line. It is also possible to adopt a structure in which the insert molding is performed and the integral molding is performed. According to this configuration, since the printed wiring board 34 on which the magnetic core 37, the current sensor 33 are mounted, and the lead wire 36 are integrally formed, the lead wire support 35 is fixed to the case 38 as in the above embodiment. There is no need to do it. Therefore, the productivity of the current detector 31 is improved.

  In the above embodiment, the configuration in which the conductor 32 is fitted to the case 38 by the protrusion 38d and the groove 32c has been described. However, the present invention is not limited to this configuration. For example, the conductor 38 may be set in a molding die of the case 38 when the case 38 is molded, and the case 38 and the conductor 32 may be integrally molded.

  Fig.7 (a) is a partially broken front view of the watt-hour meter 41 provided with the current detector 31 shown in FIG. 6, and the same figure (b) is the partially broken side view.

  The watt-hour meter 41 has a terminal block 42. The terminal block 42 is provided with equipment terminal fittings 43a and 43b connected to the power supply side electric wire and equipment terminal fittings 44a and 44b connected to the load side electric wire. ing. The adjacent equipment terminal fitting 43b and equipment terminal fitting 44a are connected by a connection plate 45 fastened by a terminal screw 48 having conductivity, and the separated equipment terminal fitting 43a and equipment terminal fitting 44b are connected to a printed wiring board 46. Is connected by a current line 47 which is wired below and fastened by a terminal screw 48. Each current detector 31 includes a conductor between the connection plate 45 constituting the connection terminal and the equipment terminal fitting 44a, and between the terminal portion 47a in which the end portion of the current wire 47 is bent into a circular shape and the equipment terminal fitting 44b. 32 is held by being fastened by a terminal screw 48 and attached to the watt hour meter 41. For this reason, each current detector 31 detects a current flowing through a load-side electric wire (not shown) connected to the device terminal fittings 44 a and 44 b as a current flowing through a current path formed by the conductor 32 and the terminal screw 48.

  According to the present embodiment, it is not necessary to penetrate the current detector 31 in each of the device terminal fittings 44a and 44b as in the conventional watthour meter 11b shown in FIG. For this reason, the device terminal metal fittings 44a and 44b are processed to have a narrower width and a processing cost is required, or the inner diameter of the through hole of each current detector 31 is increased to increase the core material cost. The terminal block 42 is not increased in size due to an increase in pitch.

  Further, since the conductor 32 is fixed perpendicularly to the device terminal fittings 44a and 44b by the terminal screw 48 and no bending stress is generated in the conductor 32, the strength of the conductor 32 is increased and the conductor 32 is extremely resistant to vibration and impact. Therefore, unlike the conventional watt-hour meter 11a shown in FIG. 2, there is no need for a fixing member for preventing the deformation of the current line 14, and the attachment work becomes unnecessary, and the material cost is not increased. Further, the connection plate 45 is manufactured by pressing a plate material, and unlike the conventional watt hour meter 11a shown in FIG. 2, it is not necessary to bend the wire material of the current line 13, and the processing cost is also reduced. .

  Further, as in the conventional watt-hour meter 11a shown in FIG. 2, it is troublesome to penetrate the current detector 1b through the current line 13 after the pitch between both ends of the current line 13 is made wider than the pitch of the terminal fittings 15 and 15. Is no longer required. Further, unlike the conventional watt hour meter 11a shown in FIG. 2, the current line 14 does not have to be passed through the current transformer 1b mounted on the printed wiring board 12. The total length does not have to be as long as that of the current line 14, and the wire material cost can be reduced. In addition, since the insulation distance inside the watt hour meter 41 can be afforded, the printed wiring board 46 can be downsized. Furthermore, since the current line 47 is shortened and the connection plate 45 can be used, the wiring member is not damaged by vibration or impact.

  In the above embodiment, the case where the current detector according to the present invention is applied to a circuit breaker and a watt hour meter has been described. However, other power distribution devices and other devices in which a connection terminal is fastened to a device terminal with a terminal screw. It is also possible to apply the current detector according to the present invention. Even in this case, the same effects as those of the above-described embodiment can be obtained.

DESCRIPTION OF SYMBOLS 21 ... Circuit breaker 24 ... Crimp terminal metal fitting 25, 48 ... Terminal screw 26, 44a, 44b ... Equipment terminal metal fitting 31 ... Current detector 32 ... Conductor 33 ... Current sensor 34 ... Printed wiring board 35 ... Lead wire support 36 ... lead wire 37 ... magnetic core 37a ... gap 38 ... case 41 ... watt hour meter

Claims (1)

A core made of a magnetic alloy having a gap;
An insertion hole having an outer diameter inserted into the through-hole of the core and a height higher than the height of the core in the through-hole direction and arranged substantially concentrically with the through-hole is formed and inserted into the insertion hole. The core in which the through-hole is disposed substantially concentrically with the insertion hole is fastened between the device terminal and the connection terminal connected to the device terminal by a screw having conductivity. A conductive conductor held between the connection terminals;
A current sensor arranged in the gap to detect a magnetic flux generated in the core in the gap and detect a current flowing in a current path formed by the conductor and the screw between the device terminal and the connection terminal; A current detector for the configured equipment terminal.

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