JP5687460B2 - Current sensor - Google Patents

Description

  The present invention relates to a clamp-type current sensor in which a current detection coil is wound around an openable and closable magnetic core disposed around a conductor to be measured. More specifically, the present invention is easily applied to a crowded wiring location. The present invention relates to a current sensor applicable to the above.

  A clamp-type current sensor has an annular sensor part that can be opened and closed. Even if the conductor to be measured is a live wire, the sensor part is arranged around the conductor to be measured and flows to the conductor to be measured. It is useful at the measurement site because it can measure current.

  This type of current sensor can be divided into the presence and absence of a magnetic core, and a magnetic core type (see, for example, Patent Document 1) in which a sensor part is a clamp arm that can be opened and closed by winding a detection coil around the magnetic core. There is an air core type using a Rogowski coil in which a coil is wound around a tube having electrical insulation and flexibility in a sensor portion (see, for example, Patent Document 2).

JP 2008-267951 A JP 2006-329826 A

  In the magnetic core type, since the magnetic flux due to the current flowing in the conductor to be measured is collected in the magnetic core, it can be detected with high accuracy even at a low current. On the other hand, since the magnetic core is hard and not flexible, there is a problem that the target conductor to be measured cannot be grasped well in a crowded wiring location.

  On the other hand, in the case of the air core type by the Rogowski coil, since it is rich in flexibility, it can be easily attached to the target conductor to be measured even in a crowded wiring location. There is a problem that it is not suitable for low current measurement because there is no magnetic core for collecting magnetism.

  Therefore, an object of the present invention is to provide a current sensor that can be easily attached to a conductor to be measured even in a crowded wiring location, while having a high ability to collect magnetism and thus enabling low current measurement. There is to do.

In order to solve the above-mentioned problem, the present invention provides a current sensor comprising a sensor body having a magnetic core arranged in a ring around a conductor to be measured and a detection coil wound around the magnetic core. However, both end portions are separated, and the both end portions are flexible so that they can be rounded as a joint portion by butting or overlapping , and hold the joint portion of the magnetic core. The holder includes a first holding groove into which one end of the magnetic core is inserted, and a second holding groove into which the other end of the magnetic core is inserted. The holding groove and the second holding groove are characterized by being formed in a V-shape that allows both end portions of the magnetic core to be butted .

  The magnetic core may be in the shape of a round bar, but in order to allow the magnetic core to pass through a narrow gap in a crowded wiring location, the magnetic core has a thickness of 0.2 to 1.0 mm. It is good to form in plate shape.

  In order to give flexibility to the magnetic core, the magnetic core is preferably composed of a laminate of a plurality of core sheets formed in a band shape.

Also, a spacer member formed in a V shape is provided between the first holding groove and the second holding groove so that the conductor to be measured does not approach the joint portion of the magnetic core. It is preferable.

  The detection coil may be wound directly around the magnetic core by a winding machine or the like, but it is preferable to fit a plurality of coil elements having a predetermined number of turns into the magnetic core, By reducing the width of each coil element, the flexibility of the magnetic core can be improved.

  In the present invention, the coil elements may be connected in series or in parallel.

  According to the present invention, in a current sensor comprising a sensor body having a magnetic core arranged in a ring around the conductor to be measured and a detection coil wound around the magnetic core, the magnetic core has both ends. Because it is separated and has flexibility that can be rounded as a joint part by joining or overlapping the above-mentioned both ends, it has high magnetism collection capability, and therefore low current measurement is also possible However, it can be easily attached to the conductor to be measured even in a crowded wiring location.

The perspective view which shows embodiment of the sensor main body with which the current sensor of this invention is provided. The perspective view which shows the magnetic core of the said sensor main body. The perspective view which shows the attachment state of the coil element with respect to the said magnetic core. The side view which shows the preferable form of the junction part of the said magnetic core. The perspective view which shows the 1st holder as reference embodiment holding the junction part of the said magnetic core. The perspective view which shows the holding | maintenance state of the junction part by the said 1st holder. The perspective view which shows the 2nd holder by embodiment of this invention holding the junction part of the said magnetic core. The perspective view which shows the holding | maintenance state of the junction part by the said 2nd holder.

  Next, some embodiments of the present invention will be described with reference to FIGS. 1 to 8, but the present invention is not limited thereto.

  Referring to FIG. 1, the current sensor of the present invention includes a sensor main body 1 in which a detection coil 20 is wound around a flexible magnetic core 10 as the sensor main body.

  The magnetic core 10 has both end portions 10a and 10b separated, and at the time of measurement, the both end portions 10a and 10b are rounded around a conductor to be measured (not shown) as a joint 10c by overlapping, for example, and a closed magnetic circuit Form. Both ends 10a and 10b may be butted together to form a joint 10c.

  As shown in FIG. 2, the magnetic core 10 is formed in a band plate shape. The magnetic core 10 may be formed as a single band plate, but a plurality of core sheets formed in a band shape with a wide permalloy material or electromagnetic steel plate having a thickness of about 0.1 to 0.2 mm are stacked. A laminate is preferred.

  In terms of easy bending, 2 to 5 core sheets to be laminated (0.2 to 1.0 mm in total thickness) are appropriate. In this embodiment, two core sheets 11a and 11b are laminated. The laminated structure of the core sheet may be held by an adhesive or caulking.

  As described above, when the magnetic core 10 is, for example, a laminated body of two core sheets 11a and 11b, in order to reduce the magnetic resistance of the joint portion 10c and increase the sensitivity, as shown in FIG. It is preferable that both end portions of 11b are alternately overlapped and joined in contact with each other.

  Although the detection coil 20 may be wound directly on the magnetic core 10, as shown in FIG. 3, it is produced by fitting a plurality of coil elements 21 wound in advance as a predetermined number of turns on the magnetic core 10. It is preferable in terms of properties. The coil element 21 may be “with bobbin” or “without bobbin” as a winding core.

  As described above, when a plurality of coil elements 21 are fitted to the magnetic core 10, it is preferable that the width of each coil element 21 is narrower without impairing the flexibility of the magnetic core 10.

  Further, the connection of each coil element 21 may be either a serial connection or a parallel connection. In any case, a shunt resistor, for example, is connected between the coil lead wires (not shown) from the magnetic core 10 and, for example, a shunt resistor is connected to the measurement coil (not shown) via the shunt resistor. Output as voltage.

  In the case of low current measurement applications, as an example, it is preferable that the width of the magnetic core 10 is 50 mm, the length is 500 mm, and the number of turns of the detection coil 20 is about 100 turns.

Next, a holder for holding the joint 10c of the magnetic core 10 will be described. The form state of the holder, the first holder 20 shown in FIG. 5, there is a second holder 30 shown in FIG. 7, the first holder 20 shown in FIG. 5 is a reference embodiment shown in FIG. 7 The second holder 30 is according to an embodiment of the present invention.

  Referring to FIGS. 5 and 6, the first holder 20 has a substantially U-shaped cross section, and is preferably a holding frame 21 formed in an arc shape having substantially the same curvature as that of the annular magnetic core 10. It has.

  The inside of the holding frame 21 is partitioned into a first holding groove 20a and a second holding groove 20b by a partition plate 22 formed in an arc shape with the same curvature. As shown in FIG. 6, the first holding groove 20a is divided. One end 10a of the magnetic core 10 is fitted inside, and the other end 10b of the magnetic core 10 is fitted inside the second holding groove 20b.

  Thereby, the sensor main body 1 is annularly arranged around a conductor to be measured (not shown), and the joint portions 10c at both ends thereof are held by the first holder 20 to form a closed magnetic circuit.

  In the embodiment of FIG. 6, both end portions 10 a and 10 b of the magnetic core 10 are held in the first holder 20 with the detection coil 20 (coil element 21) wound thereon. Only the both end portions 10a and 10b of the magnetic core 10 may be held in the first holder 20 without winding the detection coil 20 around the portions 10a and 10b.

  Further, as a modification of the first holder 20, the inside of the holding frame 21 is formed as one holding groove without providing the partition plate 22, and both end portions 10 a and 10 b of the magnetic core 10 are joined so as to face each other in the holding groove. May be.

  Next, referring to FIG. 7 and FIG. 8, the second holder 30 has a holder body 31 that is substantially Y-shaped, and both end portions 10 a and 10 b of the magnetic core 10 are butted in the holder body 31. In order to make it possible, a first holding groove 30a into which one end 10a of the magnetic core 10 is inserted and a second holding groove 30b into which the other end 10b of the magnetic core 10 is inserted are formed in a V shape. Yes.

  In this embodiment, below the intersection of the first and second holding grooves 30a and 30b, there is further provided a third holding groove 30c in which the joint portions 10c of both end portions 10a and 10b of the magnetic core 10 are disposed. It is connected continuously.

  In addition, a spacer member 32 is formed integrally with the holder main body 31 between the first holding groove 30a and the second holding groove 30b so as to prevent the measured conductor from approaching the joint portion 10c. ing.

  According to the second holder 30, as shown in FIG. 8, one end 10a of the magnetic core 10 is inserted into the first holding groove 30a, and the other end 10b of the magnetic core 10 is inserted into the second holding groove 30b. By inserting into the inside, the both end portions 10a and 10b are joined in the third holding groove 30c to form a closed magnetic circuit, and the sensor body 1 is arranged around the conductor to be measured as a balloon.

  Even in this case, both ends 10 a and 10 b of the magnetic core 10 may be held in the second holder 30 without winding the detection coil 20 around the both ends 10 a and 10 b of the magnetic core 10.

  The first holder 20 and the second holder 30 are made of a nonmagnetic material such as a synthetic resin in order to reduce the influence on the measurement value due to the position of the conductor to be measured (the center position or a position shifted from the center) in the sensor body 1. Preferably it consists of.

  According to this sensor main body 1, since the magnetic core 10 is in the shape of a strip, it can be easily attached to a target conductor to be measured even in a crowded wiring location, but it can be easily bent. The magnetic core 10 may be a round bar as long as it is provided.

DESCRIPTION OF SYMBOLS 1 Sensor main body 10 Magnetic core 10a, 10b End part of magnetic core 10c Joining part of magnetic core 11a, 11b Core sheet 20 Detection coil 21 Coil element 20 First holder 20a, 20b Holding groove 21 Holding frame 22 Partition wall 30 First holder 30a, 30b, 30c Holding groove 31 Holder body 32 Spacer member

Claims (6)

In a current sensor comprising a sensor body having a magnetic core arranged in a ring around a conductor to be measured and a detection coil wound around the magnetic core,
Both ends of the magnetic core are separated, and the both ends are flexible so that they can be rounded as a joint by butting or overlapping , and hold the joint of the magnetic core With a holder made of non-magnetic material,
The holder has a first holding groove into which one end of the magnetic core is inserted, and a second holding groove into which the other end of the magnetic core is inserted, and the first holding groove and the second holding groove. The holding groove is formed in a V shape that allows both end portions of the magnetic core to be butted together. A spacer member formed in a V shape is provided between the first holding groove and the second holding groove so that the conductor to be measured does not approach the joint portion of the magnetic core. The current sensor according to claim 1. Current sensor according to claim 1 or 2 said magnetic core, thickness, characterized in that it is formed in a band plate of 0.2 to 1.0 mm. The current sensor according to claim 3 , wherein the magnetic core is formed of a laminate of a plurality of core sheets formed in a band shape. The detection coil includes a plurality of coil elements having a predetermined number of turns, current according to any one of claims 1 to 4, each of which is characterized in that it is fitted to the magnetic core Sensor. The current sensor according to claim 5 , wherein the coil elements are connected in series or in parallel.

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