SU140903A1 - Pliers for measuring large constant currents - Google Patents

Description

Pliers for measuring large direct currents in conductors are known. But they have a number of disadvantages: they can measure current only when they are closed or flared, i.e. they are unsuitable for continuous current measurement, besides, the meter in them is a fluxmeter, i.e. a ballistic gauge, possessing large inertia and high cost.

Offered ticks do not have these disadvantages. They use the Hall effect in semiconductors, which makes it possible to measure the true value of the current without opening and closing the tongs for as long as the conductor is gripped by the device’s arm. In addition, a fluxmeter is not required to measure current, which simplifies the instrument and facilitates its use. In order to enhance the magnetic induction, it is possible to use a circuit made of a magnetically soft material with a large number of air gaps, ensuring the straightness of the instrument's chalices.

FIG. 1 shows ticks. They consist of two handles 7, a measuring device 2 of the type M-24 and a measuring contour (RMA) 3 made of a soft ferromagnetic material. The same air gaps (from 100 to 300) are located uniformly around the circumference of the RMA, with a size of the order of iO -10 ml {., In which an equal distance from each other is 5-8 pieces of emf sensors. Hall (semiconductor devices made of germanium p 22 ohm cm). The device has the following data: excitation circuit voltage 3.3 V (from a KBS-L-0.50 battery), excitation current of all sensors 16.5 ma, measuring device M-24, class 0.1 X00 µA with internal 690 ohm impedance. The diameter of the frame is 20 cm, the diameter of the protective ring, made of a dielectric, is 15 cm, which allows to cover the area calculated for the current up to 10 ka.

No. 140903-2. In FIG. Figure 2 shows the electrical circuit of the clamp meter. Here RI, RZ, RZ, RA are the resistances ensuring the same potential of all Hall electrodes and connected in series with the sensors; D rheostat setting a fixed voltage; P2 is a voltage divider used to correct the device when the f excitation current is turned on; Ki - power button; KS button dkdyucheni. meter; DS - additional resistance; TK.S - tbrmbkomniruyuschee resistance of 580 ohms. It is made of germ9Ts1 -. (r - I84 om. see).

The potentials of all the Hall electrodes, in the absence of a magnetic field, must be the same on all sensors, which is done by turning on the resistances i -. The Hall sensors are connected in parallel and the average value of their voltage will always be proportional to the measured current. The operation of the clamp meter is based on this principle.

These tongs make it possible to measure large direct currents up to 10,000 A with an accuracy not exceeding 2.5%.

Subject invention

Claims (2)

1.Ticks for measuring large constant currents, characterized in that, in order to measure the current without breaking and closing the circuit for a long time, n Hall sensors, uniformly distributed in the air gaps along the circuit of ticks and connected in parallel, are applied so that the average value the voltage of the Hall is proportional to the measured current, when the law of total current is fulfilled with a given accuracy. 2. Clamp pliers according to claim 1, characterized in that, in order to enhance the magnetic induction, a circuit made of a magnetically soft material with a large number of air gaps, ensuring the straightness of the instrument scale, is applied.