SU33601A1 - Electric meter - Google Patents

Description

Measurements of some electrical quantities are available with instruments that allow you to count the ratio of the strengths of the currents flowing in two different circuits. An uneven magnetic field, which is a feature of such devices, is achieved in existing devices by the fact that pole shoes and the core form a gradually widening annular gap.

The present invention aims at obtaining a non-uniform magnetic field in a strictly cylindrical annular gap with the help of an obliquely cut core.

In FIG. 1 shows schematically a general view of the proposed device; FIG. 2 is a cross section along the line / - / in FIG. one; FIG. 3 is an incision along the line // - // in FIG. one; FIG. 4- sweep ring-shaped sedentary.

The proposed device consists of a double moving frame of the usual type, both windings of which, rigidly fastened together, are located in the same plane so that the outer parts of the windings rotate in an annular gap between the ring-shaped core C and the pole shoes B, having an internal cylindrical recess, strictly coaxial with the outer surface of the core. Ser (200)

The bar is cut at a certain angle to its axis by a certain, for example, cylindrical, surface parallel to its forming diameter connecting the middle of the shoes.

The direction of the currents in the windings of the frame is chosen so that, due to the interaction with the magnetic field, each of the windings will tend to shift towards the short generator core. The direction of the electromagnetic forces acting on the frame in the proper direction is shown in FIG. 1 by arrows and FZ- Thus, if the current in the right winding is clockwise, in the left it is directed counterclockwise, and the direction of the currents is consistent with the direction of the magnetic field so that the windings tend to turn into the zone of shorter core .

If a current flows through one of the windings having, for example, an equal number of turns, stronger than the other, and if in the initial position the frame is located in a plane passing through the middle of the shoes, then one of the F, Fy forces, for example, the F force will be greater than 2 and the frame will begin to rotate. But as the frame rotates, the force FI will start to decrease, since the winding through which the stronger current passes will begin to enter the zone of the shorter cores, and the force F will increase accordingly, as the winding with the weaker current will start to enter the zone of the longer corers . If the difference between the forces of the currents in the windings is not excessive, the power of FI and FZ will at some point compare and take the position defined by the equation: ii "1/1 4 Sch. H where the current in the windings, n is the number of turns in them , - the lengths of those forming the core, against which the frame has stopped. As is well known, the force acting on a conductor element placed in a magnetic field, through which an electric current flows, is equal to: l j: H .g. Sin (B, As) .is ,, 4 P () where // is the magnetic the floor, in gauss, i is the Walk force in amperes, AS, is the length of the conductor element, D is the displacing force in. grams. Considering that the internal parts of the coil are inside the iron core, where the field voltage is close to zero, the interaction of these parts of the windings with the magnetic field is neglected. So, on the frame there are two forces FI VI FZ (Fig. 1), creating two modes; cop; r and, hert r - frame radius. Moments are directed oppositely. Equilibrium framework is possible with equality: ...... (2) what gives when the constant /:. :. . . . (2a) Each of the forces. (I or) is an integral of the form / B. i. n (sin (H,. &.). & -9810. (i.e. with the “H instructions” shown in Fig. 1-3, g. p. 9810 where / is the winding length located with under the action of a magnetic field, a is the number of consecutively connected winding coils.The development of the lateral surface of the core, for example, has a sinusoidal flat section (Fig. 4). The average position of the windings having a certain width B is indicated by shaded strips. the floor length of the uniformly wound windings of the frame is defined as the mean ordinate of the shaded Surface i.e. with the middle position of the frame as: / A + A f - 2 where L and AZ are the smallest and largest generatrix of the core. If the frame is rotated from the initial symmetrical position to some other one defined by the angle of rotation p5 (FIG. 4) one of the windings will be under the action, the flux on the length / 1, and the Friend on the length / z- Long and li and / 2 can be found from the following ratios: / + 2S 1 - 2B J fei-f / IS 2 2 1If where 5 - area-equal:, hi - / c g r sin with d cs -1Г - / 12 „.. B 2- G. 2 Sin cc sin -g- In view of the smallness of the angle -we assume B because of of which: -Bsino) Substitute the value found S Equation (b), and (7), we have: J Y1 -ji «La - -. (6а) k - -2, 7li + Лг I Tit - AI / 2 -4 -, + Sin cf 2 (e) If the NUMBER of series-connected turns in the first winding is I,

and in the second 1C, the electromagnetic forces FI and FZ are equal:

E- g. tin / Ld + h Rg - fti.

 98lO, 2,

n-jff. ha A2 / 7, + fej. Yyyy-yy. /, „,

2,810 - (- Tb- sm 9J (lOa)

where Zj and / 3 are the forces / currents flowing in the windings.

Meaning equations 2 and 2a

/ „F +

AJ -t 7n. L.) h «1 (J. (L, ya -7. / ,,, Z2« 2 (2 j -01)

From% 7i2, arcsinA ± 4 g, d, + g, ,, (2) тAs -AI Equation (12) shows that the angle of rotation of the frame does not depend on the voltage of the magnetic field H, nor on the electromotive force, generating currents ii and 112 (since one source ed was used to generate currents) The last circumstance becomes if substitution r is replaced by equation (12) and i their equivalent ones are replaced by / 1 1; 7

where E is the voltage source e. .with. and TJ and g are the resistances of the respective circuits, then:

AND

-n ,,

fti + 7ti

(12b)

arc sm

 E, E ft, -7

ir- "2-t - 7r-" 2

or:

7 (, 4-D «W, - G. J

D) arc,. (14)

tch "8% rs" 1 + ri "2

It follows from equation (14) that the proposed device is suitable for measuring resistances. The subject matter of the invention. An electrical measuring device, the movable frame of which consists of two independent windings located in one plane and a winding, in the inter-iron space of the same, along the frame rotation path, the width formed by the pole bashmaks and the inner core, differing in that, in order to obtain an uneven field with a correct cylindrical surface of the notch of the shoe B, the inner ring-shaped core has a different height along the frame rotation path.

: t It;