SU789759A1 - Electromagnetic modulator - Google Patents

Description

I

The invention relates to measuring, fielding technology and can be used in devices for automatic control, control and monitoring of electrical and mechanical parameters, in particular, for converting a constant voltage to an alternating voltage.

Known magnetoelectric recording measuring device, Yu containing an internal ferromagnetic cylinder with. the grooves in which the excitation winding is placed, the external magnetic conductor located coaxially with respect to the internal ferromagnetic cylinder, and in the cavity between the cylinder and the external magnetic conductor there is an electrically conductive element with the possibility of its longitudinal movement 13.20

A disadvantage of the known magnetoelectric recording meter is the low sensitivity.

Also known is an electromagnetic modulator 25 with a variable inductance in the circuit of the modulating signal, consisting of a magnetic conductor, alternating and direct current windings arranged mutually perpendicular to p- 30

However, the magnetic core is made in the form of two concentric cylindrical cores arranged relative to each other, closed at one end, and in the cavity between the cores there is a movable DC winding p.

The disadvantage of this electromagnetic modulator is also low sensitivity due to the non-differentiation of the design, high magnetic resistance in the path of the working magnetic flux, caused by a large air gap. In this case, the change in modulated magnetic resistance is small compared to the total resistance, which reduces the modulation depth, output power and sensitivity, and necessitates an increase in the magnetizing force of the modulating winding.

The purpose of the invention is to increase the sensitivity of the electromagnetic modulator, as well as to ensure the possibility of its linear regulation.

This goal is achieved due to the fact that an electromagnetic modulator containing a magnetic core consisting of two cylindrical spherical connectors coaxially arranged relative to each other, between which a ferromagnetic washer is located at one end, an alternating current excitation winding placed on the ferromagnetic cylindrical cores in their longitudinal perpendicular to her located DC winding, placed on the inner ferromagnetic cylindrical core, and measuring The coil, on the side of the other end between the ferromagnetic cylindrical cores, is placed on the second ferromagnetic washer, and the direct current excitation winding is made in two sections interconnected sequentially between the strips and placed directly under the ferromagnetic washers, and the measuring winding is placed in a screw groove made on the outer side of the inner ferromagnetic cylindrical core, and in the cavity between the ferromagnetic cylindrical cores is located ring a ferromagnetic core with the possibility of its longitudinal movement.

The drawing shows schematically the design of an electromagnetic modulator.

Electromagnetic. the modulator consists of two cylindrical ferromagnetic cores 1 and 2 located coaxially and closed at both ends by ferromagnetic washers 3. In the gap between the cylinders there is a movable ferromagnetic core 4. On the surface of the inner cylinder there are slots with a winding 5, the other two windings are made so that the magnetic fluxes from them are mutually perpendicular. The winding 6 is made of two sections and a section of the winding, connected in series, at the ends of the magnetic circuit, the winding 7 covers both cores and is connected via a diode 8 to an alternating current source.

The device works as follows.

Winding 7 is connected to an alternating current source (not shown in the drawing and creates in the magnetic core a transverse alternating magnetic field, under the action of which the specific / magnetic resistance varies ffc according to the law:

ModH

R

db

-9

Since p varies with double frequency with respect to changes in B and H, winding 7 is connected to the power supply through diode 8.

For the design with selected parameters, with the length of the rolling

the core is 15 cm and the gap between the movable core and the cylindrical cores is 0.2 mm. (idle fit) is the coefficient determining the modulation depth of the magnetic one. resistance equals:

V A-RI (PS; op ° / °

 | p | -p. cn hsig J2; b,

Where; R- magnetic resistanceLTg .- lOQofo ™ ®

-change magnetic

Mg resistance in% relative to total resistance;

- the length of the magnetic flux path;

- the area of the magnesium section of the ground conductor along the path of the constant magnetic flux;

- area of air gap over which constant magnetic flux is recorded;

b - the gap between the movable

and cylindrical cores.

Excitation winding 6 is connected 0 to the source of a modulated direct current signal (thermoEMF), and a longitudinal magnetic flux appears in the magnetic circuit. As the magnetic resistance of the magnetic circuit changes, an emf is induced in the output measuring winding 5.

"- 2L W GH

where: W - the number of turns distributed

windings 5, F - winding magnetizing force

b;

1 is the path length of the magnetic flux (does not change with x),

Dependence (1) can be written in the form. .

0 E S.X., (2) where; S is the sensitivity of the modulator by displacement .;

Crw

whence it is seen that with decreasing & the sensitivity decreases (decreases t) and at 5 O. (there is no alternating signal in the winding 7) b O, the output signal is zero and at. the coordinate of the core 4, while in the known device there is no winding position in which

the output would be zero.

The sensitivity of the proposed electromagnetic modulator compared to the known 1.5-2 times higher. From the expression (2). It is evident that

Moving the moving core 4 in the cavity between the two cylindrical cores 1 and 2 allows the modulator sensitivity to be adjusted linearly.

The proposed design can be used in devices for converting and amplifying weak electrical signals, as well as converting mechanical quantities into electrical signals. Its charter feature is high sensitivity, linear dependence of the output signal on the coordinate of the moving part, high reliability, complete shielding from external electromagnetic fields.

Claims (2)

1. Electromagnetic modulator containing a magnetic core consisting of two cylindrical cores coaxially arranged relative to each other, between which a ferromagnetic washer is located at one end, an alternating current winding placed on ferromagnetic cylindrical cores in their longitudinal plane perpendicular to its winding direct current, placed on the inner ferromagnetic cylindrical core, and measuring winding, characterized in that, in order to increase from the other end between the ferromagnetic cylindrical cores placed second ferromagnetic washer, and the excitation winding of direct current is made in the form of two sections interconnected in series and counter and placed directly under the ferromagnetic washers, and measuring 5, the winding is placed in a screw groove, which is filled on the outer side of the inner ferromagnetic cylindrical core. 2. A modulator according to claim 1, characterized in that, in order to ensure the possibility of a linear sensitivity control, in the cavity between the ferromagnetic cylindrical cores there is an annular ferromagnetic core with the possibility of its longitudinal movement. Sources of information taken into account in the examination 1. USSR author's certificate D No. 605182, cl. G 01 R 5/02, 1978. 2. USSR author's certificate number 446837, cl. G 01 R 15/06, 1974.  VM /// r ///////// y / 7 // 7A 17 is k- k5 (X)