SU976388A1 - Current pickup - Google Patents

Description

The invention relates to electrical measuring technology and can be used to indicate alternating currents with a frequency spectrum from fractions of a hertz to several megahertz.

A comparison element is known, containing two transformers, each of which is provided with two primary and one secondary winding, and a ferrite rod, piercing the windings of one of them f1}

The disadvantage of the comparison element is low accuracy due to the influence of disturbing fields and low thermal stability.

A current sensor is known, which contains a source of reference voltage, and toroidal ferromagnetic cores with a rectangular hysteresis loop, with bias-mounted windings, primary windings connected in series, and secondary windings to which display elements 1G2 are connected.

A disadvantage of the known device is also low noise immunity and thermal stability, leading to deviations of the working magnetic flux in the cores, and, therefore,

to reduce accuracy. In addition, the presence of a source of reference for example v in the known device leads to the complication of its design, reducing efficiency and service life.

The goal is achieved by the fact that a current sensor containing M ferromagnetic cores with a rectangular hysteresis loop, with primary windings on them connected in series, and secondary windings and display elements, an armature gorgpk-shaped permanent magnet is inserted in it, the cores are in the form The primary windings of the (2i) -th and (2i-+1) -th cores are switched on, the secondary windings of the specified cores are connected in series according to and connected to the corresponding element entu indication core longitudinal axis coincides with the direction of the magnetic field of the permanent magnet, and the magnitude of the coercive force of the permanent magnet satisfies a condition

 2H

.

her

whereH is the coercive force of armor

cnw.

Claims (2)

pot magnet, ss coercive force of core material. Figure 1 shows a longitudinal section of the sensor current and a winding connection circuit for AND 1; Fig. 2 is an external view of a pot-shaped armored type permanent magnet. The current sensor consists of an even number (at least two) of the same ferromagnetic cores 1, each of which has primary windings 2 and secondary windings 3 wound. Primary windings 2 are connected in series and pair-counter, which provides compensation for the induced emf interference. The secondary windings are connected in pairs according to and connected to the corresponding element 4 of the display. The working flow in the cores 1 is created by an armored pot-shaped permanent magnet 5. The size of the working flow is controlled by changing the gap dX. The device works as follows. When the primary windings 2 are connected to the circuit to be measured, a current flows in the windings, creating a magnetic field in the cores that is opposite to the operation, i.e. the measured signal is compared with the own discrete level of the reference element formed; about the i-th main and i-th additional cores 1; If the algebraic difference of the reference field and the field of the measured signal exceeds the dynamic coercive force of the cores, then impulse signal or in the period they will re-magnetize, and then return to their original state under the action of the field of the permanent magnet 5. At the same time, the permanent magnet 5 that creates the reference field cannot be re-magnetized, to how its coercive force exceeds that in cores 1. Remagnetization of cores 1 leads to the appearance of an emf in the secondary winding 3, which is detected by means of the display element 4, for example, an LED. The number of pairs of cores 1 is chosen equal to the number of discrete reference levels required. The disk is created by changing the number of turns in the primary windings 2 or by quantizing the reference fields by rotating the value of HL in each element of the comparison, and the measurement range can be set by simultaneously changing the magnetic gap in all elements. The permanent magnet 5, which is the source of the working flux in the cores 1, is at the same time an effective magnetic shield, which makes it possible to significantly increase the noise immunity of the device. In addition, the exclusion of the source of the reference voltage or the generator and the bias windings makes it possible to significantly simplify the device and increase its thermal stability and reliability. The proposed current sensor can be used as an integral part of measuring devices without moving parts for measuring variables and pulse currents, as a converter of analog signals into a parallel code with a unified waveform. Claims of the invention A current containing ferromagnetic cores with a rectangular hysteresis loop, with primary windings arranged in series with them connected in series, secondary windings and display elements, characterized in that, in order to improve accuracy, a constant armored pot-shaped is inserted into it. magnet, cores are made in the form of rods, with the primary windings of (2i) -s and (2i + 1 -th cores included opposite, the secondary windings of these cores are connected in series-according and connected The longitudinal axis of the cores coincides with the direction of the magnetic field of the permanent magnet, and the magnitude of the coercive force of the permanent magnet satisfies the 2-Hc condition hf-n, the coercive force of the armored pot-shaped magnet, c - coercive force of the heart material. Sources of information taken into account in the examination 1. The author's certificate of the USSR If 144055, class C 05 1/01, 1961. 2. US Patent 2,962,704, cl. 340347, 1961.