JPH0296663A - Clamp-type ammeter - Google Patents

Abstract

PURPOSE:To eliminate a positional error in a measured current value and also to reduce the cost by disposing air-core coils on the same plane, by connecting them in series and by detecting a magnetic field generated by an alternating current flowing through a conductor to be measured. CONSTITUTION:A plurality of coils 2 wound on a magnetic core of plastic resin are connected in series on the same plane and fixed on resin 3 for fixing the coils. When a clamp-type sensor element is closed at the time of measurement, the coils 2 are connected together by a contact 18. By detecting a magnetic field generated by an alternating current flowing through a conductor to be measured, in this constitution, it is made possible to eliminate a positional error in a measured current value and to reduce the cost.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a current sensor that measures the current flowing through a conducting wire without separating the Δ-1 constant conducting wire, and a clamp-type current measurement using the current sensor. Regarding equipment.

[Conventional technology]

Conventionally, as a method for detecting the current flowing through a conducting wire without cutting off the fixed conducting wire, a coil was wound around a magnetic core made of high magnetic permeability material, and a coil was wound around the entire circumference for an air-core type. A clamp-type ammeter also used the above-mentioned current sensor.

[Problem to be solved by the invention]

However, the above-mentioned conventional technique in which a coil is wound around a magnetic core made of a high magnetic permeability material has a problem in that the measured current value varies depending on the position of the conductor to be measured. By winding the coil uniformly around the entire circumference, the problem of measurement error due to the position described above can be solved, but as with the conventional method of winding the coil around the entire circumference with an air core, The problem is that it is difficult to wind a coil around the coil, making mass production difficult.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a current sensor that is low in cost and easy to mass produce, and a clamp-type ammeter using the current sensor.

[Means to solve the problem]

(1) With the configuration in which a plurality of air-core coils and the air-core coil are arranged on the same plane and connected in series, the magnetic field generated by the alternating current flowing through the fixed conducting wire is detected. 11? Sensor (2) characterized in that it detects the current flowing through the conductor to be measured (2) A clamp-type ammeter that can determine the current flowing through the constant conductor to be measured without disconnecting the conductor to be measured, as described in (1). A clamp-type ammeter characterized by having a sensor.

〔Example〕

The present invention will be described in detail below based on examples.

FIG. 1 shows a current sensor of the present invention, and numeral 1 is a core for winding a coil, which is made of resin such as plastic. 2 is a coil. 3 is a resin for fixing the plurality of coils 2 arranged.

4 is a terminal from which the output of the coil 2 is taken out. Fig. 1 shows an example in which six coils are arranged and connected in series.

FIG. 2 is a diagram showing the relationship between the position of the conducting wire to be measured inside the sensor and the voltage generated from the sensor.

Curve 5 shows the output voltage obtained from terminal 4 when the 7111 constant conducting wire moves along the straight line indicated by 7. Curve 6 shows the output voltage obtained from terminal 4 when the conductor to be measured moves along the straight line indicated by 8. A broken line 9 indicates a range indicated by 10 in the graph in which the output voltage of the terminal 4 does not change even if the conductor position changes.

FIG. 3 is a diagram showing the relationship between the position of the conducting wire outside the sensor and the voltage generated from the sensor. A curve 11 shows the output voltage obtained from the terminal 4 when the conductor to be measured moves along a straight line indicated by 13. curve 1
2 indicates the output voltage obtained from the terminal 4 when the conductive wire to be measured moves along the straight line indicated by 14. 1
The region indicated by -5 corresponds to the region indicated by 16 in the graph, and is a range in which the output voltage of the terminal 4 is below a set appropriate voltage.

FIG. 4 is a diagram showing the relationship between the current flowing through the δPI constant conductor and the output voltage of the terminal 4. The current in the conductor to be measured and the output voltage at the terminal 4 are in a proportional relationship.

FIG. 5 is a diagram showing an embodiment in which the sensor shown in FIG. 1 is used in a sensor section of a clamp-type ammeter. Reference numeral 18 denotes an end point where the coils 2 are connected when the clamp-type sensor section is closed during measurement. 19 is a mechanism section that opens and closes the sensor section. By making the outer diameter of the clamp-type sensor section larger than the curve shown by 15 in FIG. 3, the influence of external magnetic fields can be kept below the set value. Further, by making the inner diameter smaller than the curve 9 in FIG. 2, the output voltage of the terminal 4 becomes the same value depending on the position of the conducting wire to be measured.

The example shown here uses six coils, but by increasing the number of coils used, the value of the 11FJ constant error depending on the position of the conductor to be measured can be reduced.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to eliminate positional errors such as differences in measured current values depending on the position of the δIII constant conducting wire. In addition, there is no need to wind the coil all around the sensor, and the range in which the coil is wound is small, making it suitable for mass production. Furthermore, since a magnetic core made of a high magnetic permeability material is not required, it also has the advantage of being low cost.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a current sensor of the present invention. FIGS. 2(a) and 2(b) are diagrams showing the relationship between the position of the conducting wire to be measured inside the sensor and the voltage generated from the sensor. FIGS. 3(a) and 3(b) are diagrams showing the relationship between the position of the conducting wire to be measured outside the sensor and the voltage generated from the sensor. FIG. 4 is a diagram showing the relationship between the current flowing through the conductor to be measured and the voltage generated by the sensor. FIG. 5 is a diagram in which the sensor of the present invention is applied to a clamp-type ammeter. 1 ・ 2 @ 3 ・ 4 Fist 18 ・ 19 φ Plastic magnetic core coil Resin terminal contact clamp for fixing the coil sensor Over the side of the switchgear

Claims (2)

[Claims] (1) With a configuration in which a plurality of air-core coils and the air-core coil are arranged on the same plane and connected in series, the device to be measured can detect the magnetic field generated by the alternating current flowing through the conductor to be measured. A clamp-type ammeter that detects the current flowing through a conductor. (2) A clamp-type ammeter capable of measuring the current flowing through the conductor to be measured without cutting off the conductor to be measured, characterized by having the sensor according to claim 1.