SU1267537A1 - Method of determining magnetic attraction force of two ferromagnetic surfaces - Google Patents

Abstract

The invention relates to electrical engineering, in particular to the determination of the usable magnetic attraction of mutually displaced ferromagnetic surfaces, for example, linear electric motors. The purpose of the invention is to expand the scope of application by reducing the loading force. The force of the aerostatic support 3 is applied to the ferromagnetic surfaces, which is a system: M or holes in the gap between the intersecting surfaces, or in separate rendered consoles reinforced on one of the surfaces. Often, the mutually displaced surfaces have their own aerostatic support necessary for. ensuring the operability of the device, for example, XY linear stepper motors. The pressure at the outlet of the aerostatic support P is measured by a pressure gauge 4. The iSasopa value between the ferromagnetic surfaces is measured. (About sensor 5. The surfaces load with a known force F measured by a dynamometer 6. During loading of surfaces with force F, the pressure at the entrance to the aerostatic support P is changed so that the indications of the movement indicator do not change. The magnitude of the force of the ferromagnetic surfaces is defined as O5 Fpp PF / dR, where Fy is the external load vj, an acrid force, lR is the change in pressure on the support input when applied with K / J vj

Description

load force F; P is the pressure at the inlet of the aerostatic bearing. The method is based on the proportionality of the repulsion force of the aerostatic support to the pressure at its inlet P with a constant gap between the ferromagnetic surfaces. The advantage of this method is that there is no need for a complex installation for a Cav. nor a load force equal to the force of attraction of ferromagnetic surfaces. 2 Il.

The invention relates to electrical engineering, in particular, to methods for determining the EFFORT of a magnetic attraction of mutually interchangeable ferromagnetic surfaces, for example, parts of linear electric motors.

The purpose of the invention is to expand the scope by eliminating the need for complete detachment of surfaces from one another.

Fig. 1 is a setup diagram for determining the magnetic attraction force of ferromagnetic surfaces; Fig. 2 shows the dependence of the loading force on the pressure at the inlet of the aerostatic support at a constant gap between the ferromagnetic surfaces.

The method for determining the magnetic attraction force between two ferromagnetic surfaces 1 and 2 (Fig. 1), for example, between a moving and stationary part of a linear electric motor, is as follows. The force of the aerostatic support 3 is applied to the ferromagnetic surfaces, which is either a system of openings in the gap between mutually displaced surfaces or in separate rendered consoles mounted on one of the surfaces. Often the mutually displaced surfaces have their own / aerostatic support necessary to ensure the operability of the device (for example, two-coordinate linear stepper motors with aerostatic support). The pressure P at the inlet of the aerostatic support is measured with a pressure gauge 4. , displacement indicator), the surfaces are loaded with a known force FH (detachment or compression), measured by a dynamometer 6, during loading of surfaces with a force Hz pressure P s at the inlet varied aerostatic bearing in such a way that the displacement of the indicator readings were not changed, that is, e,

t (1)

 PR dr. H

where Hz is the loading force;

.DR - pressure change at the inlet of the support when load force Rc is applied; P is the pressure at the inlet of the aerostatic bearing,

The magnitude of the force of attraction of ferromagnetic surfaces is equal to the force of repulsion of the air support, is determined by formula (1) 1, where the applied force FH of the load is the sum of the force Rc measured by the dynamometer and the weight of the part by mass.

The method is based on the proportionality of the aerostatic pushing force FOP to the pressure P at its entrance at a constant gap Q between the ferromagnetic surfaces. The constancy of the gap determines the unchanged aerodynamic drag in all parts of the support duct. In this case, the aerodynamic resistance of both individual sections and the air duct as a whole is determined by the formula

Р-Pi 7

(2)

 / i

where Z is the aerodynamic resistance of the duct; iP is the differential pressure at the inlet and

exit plot;

V - air flow aerostatic support.

Claims (1)

Experience shows the validity of expression (2) in the range of pressure variations P (0-1) Sha, characteristic of aerostatic supports. When the constants Z on all parts of the support duct, the pressure P at each point i of the duct is proportional to the pressure at its entrance, i.e. pressure P at the inlet of the aerostatic support. The lifting force Fgfl of the aerostatic support is equal to the integral of the pressure in the support gap over its area. Due to the proportionality of P and P, Fg also turns out to be proportional to P. gaps (Y between the ferromagnetic surfaces. The dependences (direct) show the magnitude of the force FJ, which should be applied to the ferromagnetic surfaces. So that, at the pressure P at the inlet of the support, the gap between In the general case, the equilibrium condition of ferromagnetic surfaces is determined by equality. PR. OP For this gap, const, which is true for each direct (F). At the points F 0 there is no external load and at the points the lifting force of the support is equal to F 0 and Fnp, i.e., the point of intersection of the direct PP {Fy) with the axis corresponds to the value of F, equal to, and also of F at a pressure P at the point of intersection of the direct () with direct FH 0. The point of intersection of the direct, {Pd,) with the axis is determined by approximation of the direct (F,) obtained at the intersection with the axis, because at this point the position of the ferromagnetic surfaces is unstable and the determination of the forces is difficult here. Here, F is 5-10% F "and may have both a positive and negative sign. The method can be applied to determine magnetic, electromagnetic, body weight, etc. The advantage of the proposed method is that there is no need for a complex installation to create a loading force equal to the force of attraction of ferromagnetic surfaces. For testing linear electric motors with aerostatic support, no additional outriggers are required; the force of attraction can be determined with the help of a manometer, a dynamometer and an indicator of displacements. In addition, the proposed method is the only one possible for testing engines on aerostatic supports, the casing of which does not have strength, allowing it to be loaded with a force equal to the force of attraction of mutually intersecting engine parts. Claims The method of determining the magnetic attraction of two ferromagnetic surfaces, such as electric machines, consists in applying a loading force to the ferromagnetic surfaces, which is recorded by a dynamometer, so that, in order to expand the field of application by eliminating the need the complete separation of the surfaces from one another, an additional force of an aerostatic support is applied to the ferromagnetic surfaces, the pressure at the inlet of which, after application of the load LfTetanus force recorded and varied until a gap between the ferromagnetic surfaces to the initial clearance, the force of magnetic attraction is determined by the formula. TG - - Jj% YR, where F is the external load force; dP is the change in pressure at the inlet of the support when a load force Fq is applied; P is the pressure at the inlet of the aerostatic bearing. Fh