JPS5833167A - Current measurement - Google Patents

Abstract

PURPOSE:To enabe accurate detection of current free from effect of magnetic hysteresis by employing the overlapping of an A.C. bias magnetic field in a current measuring clamp instrument provided with a Hall element in a close magnetic circuit. CONSTITUTION:An A.C. bias magntic field overlaps a magnetic field corresponding to current flowing through an electric circuit 4 to be measured running through a magnetic core 2 which forms a closed magnetic circuit provided with a Hall element 1 through an A.C. attenaution oscillator 6 or the like. As a result, the final magnetized point of the core 2 is determined by a magnetic resistance, a saturated magnetized point or the like and hence takes a value linearly corresponding to the current of the electric circuit 4 not affected by magnetic hysteresis. This eliminates demagnetization required for each measurement through a winding 3, a sample hold circuit 8, an indicator 9 and the like thereby enabling accurate measurement of small current with an easy operation free from effect of the magnetic hysteresis or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION This patent relates to a current measurement method using a clamp instrument having a Hall element in a magnetic path formed by a magnetic core and an air space.

At the above-mentioned 9-51 tawing meter i, the minute current is a +
*JllK is Mitsuli 1st part's lefta! Errors occur due to the influence of non-linearity of the magnetic field 9 during the movement of the external 11 nose zero point during the rounding and excessive input signals which have agricultural characteristics. This nine KJ
As shown schematically in I/en, the magnetic core cgo-sKsi* winding F of the instrument having the Hall element I is provided in the closed magnetic circuit, and the *mmmm method is applied to the ee winding a* before j1#il. Conventionally, a method of performing AC demagnetization has been commonly practiced.

However, even in 'J & good plan #k like this,
When measuring the fresh air, a measurement error occurs due to the magnitude and polarity of the input signal's magnetic flux, which is based on the magnitude and polarity of the magnetic field.

叉JIIJIiK As shown in the diagram, using the aIJ in the layer and its negative layer RK) II, the tortoise ze w7 which has been removed so that the magnetic flux of the circuit becomes zero, the tap meter ME. Then, Kazuoka wrinkles are being performed with a φ plow, but - a large input signal is suddenly applied in the outer seaweed magnetic nose of the five class mis large #1, and the response is increased. deviates from the operation of the ze w7 tutus method, i+ucs
Due to the magnetization of bribes, the relatives of Fusaku changed drastically, resulting in the error of concubines. In the above case, since the demagnetization is done manually, it is difficult to prevent the situation such as forgetting the procedure and completing the 9tk1m determination, especially when it comes to the last sentence. At the time of measurement, the measured values after magnetization 1 were unreliable.

This WA is generated by superimposing a uniformly attenuated alternating current magnetic field on the magnetic field generated by a constant current when measuring a circular current using a Tawonde meter that has a Hall element in the closed magnetic circuit. I have MI! This is related to the nine-current measurement method, which is based on the agricultural and industrial magnetization mechanism, which is characterized by excellent linearity and nine-current detection without being affected by
Next, one example of the present invention will be explained with reference to the jlJ diagram and the 1s# diagram.

As shown in JIJIIK, the magnetic path element (υ
The current detection by the zero-7 foot-tasting method, which is constructed by the winding (2) provided on the base of the magnetic core (2), is conventional and OKASI, but in this invention, the current detection is The magnetic field generated by the current in the measurement circuit (4) has a uniform Kmf
The alternating current magnetic field that generates i is superimposed on one target over four short periods. (according to the control method (1))
AC damped oscillation 41IB- and sample *- ~ donegi (8) 1aE superimposed imriarx,'sp superimposed period relation r
Drive control is performed alternately according to s. For example, in the non-superimposed period Oka TS, the output voltage of the tande meter is sampled by the control side (control side) No. 011 with a period of about several S. and then in the superimposed period TI to Nande ~ Umbrella ~ Ludo Ensai)
- Hold the directly applied non-superimposed period Hrs value as a waveform, and at the same time operate the AC damped oscillation 4W to create an AC damped magnetic field via the feedback amplifier (gradient) and winding (2). In order to supply the magnetic core (K), repeat the superposition and non-superposition alternately with the brick scrap steel as described above, and then
)''Display the weaving voltage obtained by opening (2)M(1
) that can be displayed and measured.

lI! , it shows the action memorial service of No. 1141 in the evening, so it
c is the alternating current wave carving, ip is the electric current of the subject j1 heavy electric circuit 0), the cup is the magnetic flux wave liang because the open circuit is generated by them K, the town is the sample *-kr the power voltage of the garden path The waveform shows the seabass fill l#c, so the fill I dengue is the best.)
An output voltage method that is proportional to the current to be measured Kl:lIK can be obtained. By repeating the superimposition and non-superimposition of w/i at a sufficient interval compared to the temporal change of the constant current to be measured in advance) The matter will be revealed at the meeting where I will be able to write about it.

The operating principle of this JIw method is as described in Zeng's records)) The alternating current magnetic field and IIIfJIIJIL are applied superimposed and 9 and 1 are obtained, so it is a magnetization mechanism). If there are enough stones to saturate the Jl air pressure, then the air flow will open and +V% will be completed.
11ll &< It was decided * written by the autograph of the signal magnetic field -
Laxsxpsa - Agricultural magnetization structure is used to grow one product. Shi-
Then, the total number of tafunde by this i & beak method is simply 1 ml of alternating current and the signal magnetic rise is printed after the round g! Unlike the conventional method, this method has excellent linearity and enables III-mode current measurement. Now, regarding JIIi* during the above-mentioned superimposition period, referring to Figure J showing the hysteresis of the magnetic enclosure in detail, as in the conventional system, the 11 AC #JllL signal magnetic signal 1. If you apply JIll negative Hjll, it is determined by the low layer a1 conversion to 11LKII conversion and is written. As a result, it is affected by the linearity of initial magnetization and magnetization, and Confucianism 81111 has partial layer characteristics depending on the Great Book of Gai S*kan and the value-related method, and in the worst case, Kitg' Consideration is 1
``There are times when I am magnetized by thought, and it is impossible to write a book in the summer.

-1 According to the 7m of this lI-, in the Jh insect in the 1ljs kaku, the Usui of the 51 liquid is electrified, so in the superimposed layer genus TI's Usuka Youkai, the JIg7 kaku's Niste IF through-1 “Kh-
So, I cast the major loop fnera my t-p-de and made the final II.
Around kKhJILK, you can hear the Renden. At this time, the final magnetization point is J
The resistance of the 91st step to the resistance of Il's bribe is I
It is determined at the time when the threshold of t conversion, i.e., Ire < Hz 11m e < Iwm II: signal magnetic field, Jar: intersection is determined, and the conventional method of Caofei and the part of the 114: is ff! We are the summer-wearing turtle current #I electrician. For example, convert the integral control fence (7)% into the integral μ・umbrella−I〜de field (2)−
You can use it to concentrate on Oka fishing. *S***S performs constant time-scale integration of the input, then divides 1 quasi-voltage into ms, and calculates 1
By displaying the escape time when the 1-minute voltage changes over -Denden MEK, it converts the input power into the Epp* display, so the input II minute time can be calculated according to Book 11w4. At the sample time of jl, which is the single-fold period threshold, write the inverse integration time at the Hall Y time, that is, when the superposition JII belongs to #l: and operate it. However, it is natural that it is natural, and the ground cover 1 [#) conversion is applied to the case where it is layered. For example, J
As shown in IIIK, it is possible to write -r in the 9th round of the magnetic road meeting and make the proper rotation of the conventional O-type tahunde meter MK4.

Regarding this la*, which I have explained in detail in detail, the Tafunkyo is essentially not responsible for the influence of the sub-level divinity of the Km demons.
I! It is very effective to make summer accurate current detection ■ possible in direct current measurement*, and if five superimposed and non-superimposed periods are sufficiently repeated, then alternating current can be detected. It will be difficult to show the true nature of the memorial service to JL Yi. Furthermore, KF's relaxation method is able to reduce human manipulation and prevent errors in recording measurements over a long period of time during one meditation session due to handling of measuring instruments.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing the conventional magnetization method in a clamp instrument, and FIG.
Open circuit! Shigemaro, Ayuda Kyou is the one who will destroy the power of Shikem to me.
EII I11 rope is magnetically open circuit Stekyo vX4-a
11.114 As for this matter, the threshold for bribery is based on this decision.
Number by example threshold. (Support)... Middle ~ element, (2)... Magnetic core, (2
). ――・・・Winding, ni) ・・・Electric circuit, (transfer) ＊
* Increased work, (2), d...3! ! Flowing Responsibility & Shaker, (
7). (K... Control circuit, ■, Id... 1 voice, * - LED H path, #), @f --- Display, iac -@
@ AC reduced liability current memorial service, is... measurable current memorial service, cup... generated magnetic flux liquid, %, 屹... sump ~ hold 1 circuit force wave order 1 ■ I20 Pa

Claims (1)

[Claims] 1. In current measurement using a clamp instrument with a Hall element in the open magnetic path, the signal magnetic field generated from the electrical circuit to be measured is overlaid with AC 111JF caused by a waterfall reduction current onto the magnetic path. Damn it, a current measuring method characterized by measuring the output voltage of a loop element in proportion to the above-mentioned non-superimposed 11 MIK current to be measured.