RU2364835C1 - Magnetic compass - Google Patents

Abstract

FIELD: physics, measurements.

SUBSTANCE: invention is related to the field of navigation instrument-making and may be used for destruction of electromagnet deviation in magnet indicating and induction compasses. Substance of invention is compass comprising magnetic sensitive element and electromagnet compensator comprising coils installed pairwise symmetrically relative to compass vertical, which passes through centre of magnetic sensitive element symmetry, with provision of higher efficiency of compensator by means of deviation compensation limits, axis matching with direction of magnet axis of coil is inclined relative to line that passes through centres of magnetic sensitive element coils, by angle defined by the following formula:

where α is angle between axis matching with direction of magnetic axis of coil, and line that connects centres of symmetry of coil and magnetic sensitive element; ψ is angle between vertical that passes through center of compensator coil symmetry_; and line that connects centres of symmetry of coils and magnetic sensitive element; besides, coils of compensator comprise cores of cylindrical shape from ferromagnetic low coercive material with identical dimensional size and weight; distance between centres of symmetry of cores and compass vertical and distance from centres of symmetry of cores to centre of symmetry of magnetic sensitive element are equal to each other.

EFFECT: provision of possibility to expand range of electromagnet deviation compensation with preservation of dimensional size of compensator coils, and compass, accordingly, with provision of minimisation of error in compass course indication due to variation of quadruple deviation in process of vessel or ship sailing with variation of sailing latitude.

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Description

The present invention relates to the field of navigation instrumentation and can be used to destroy electromagnetic deviation in magnetic needle and induction compasses with an expansion of the deviation compensation range, while ensuring the absence of errors in the form of a changing quarter deviation when sailing a ship, a ship with changes in latitude.

Known magnetic compass with electromagnetic compensator (EMC), consisting of a system of three mutually perpendicular solenoid coils X, Y, Z, creating respectively the longitudinal, transverse and vertical components of the electromagnetic field, described in the books "Magnetic Compass Case", Nechaev P.A ., Grigoryev V.V., M .: Transport, 1975, p. 89 (Fig. 64), p. 231-232; “The deviation of the magnetic compass”, Kozhukhov V.P., Voronov V.V., Grigoriev V.V. - L .: Maritime transport, 1960, pp. 264-265.

The main disadvantage of the compass is the location of the EMC on the vertical axis passing through the center of symmetry of the magnetic sensing element (MEC) of the compass, under the compass pot with the MEC. The indicated location of the EMC between the compass pot (see “Magnetic compass business”, position 2 in Fig. 64) and the magnets of the deviation device (position 12 in Fig. 64) necessitates a significant increase in the magnetic moments of the EMC coils, and therefore their overall dimensions , mass and value.

In addition, EMC has a low efficiency - a low value of the ratio of the magnetic moment of the coil to the mass of the coil winding.

A magnetic compass with EMC is also known, described in Compass KM 145. Technical description and operating instructions for KBO.115.071 TO, p. 19-20 (Fig. 1), in which the EMC is located at the level of MChE (see Fig. 1 , positions 12 and 13, and Fig. 3, position 6).

The main disadvantage of the compass is the need to significantly increase the overall dimensions of the compass by increasing the diameter of the upper part of the binnacle of the compass in accordance with the dimensions of the EMC coils.

Known magnetic compass described in "Compass KDE-P. Technical description and operating instructions for BWC. 115.016 TO ”, p. 5, 6, 13, 18, 21, 94, 97, fig. 4, fig. 7.

Compass KDE-P contains a sensor in which the magnetic sensing element of the compass is located (see page 5, page 18, figure 4, position 17) and deviation devices that ensure the destruction of all types of magnetic and electromagnetic deviation (see page 6 , p. 21, p. 97, fig. 7).

The electromagnetic deviation compensator consists of four cylindrical coils: two longitudinal coils X, position 32, and two transverse coils Y, position 83, located under the coils X.

Coils X are provided with two cores of ferromagnetic material, position 77. Coils Y are equipped with one core, position 82.

The main disadvantage of the KDE-P compass - an analogue - is that the cores of the coils are located at different distances from the magnetic sensor and have different masses. As a result of this, the magnetizations of the cores by the field of the sensing element differ significantly, which creates a quarter deviation of the compass, which changes with a change in the latitude of the vessel or ship. Thus, there is a changing compass heading error.

Closest to the proposed invention in technical essence is the magnetic compass according to patent No. 2161775 (application No. 99102426 of 02/09/1999) - a prototype.

The compass contains a magnetic sensing element and an electromagnetic compensator, including coils mounted in pairs symmetrically relative to the vertical of the compass, with the aim of increasing the efficiency of the electromagnetic compensator by increasing the limits of compensation for deviation per unit mass of the compensator. The magnetic axis of the coils are placed in planes passing through the vertical of the compass. The axis coinciding with the direction of the magnetic axis of the coil is inclined with respect to the line passing through the centers of symmetry of the coil and the magnetic sensing element by an angle defined by the formula

where α is the angle between the axis coinciding with the direction of the magnetic axis of the coil and the line connecting the centers of symmetry of the coil and the magnetic sensor;

Ψ is the angle between the vertical passing through the center of symmetry of the coil of the electromagnetic compensator, and the line connecting the centers of symmetry of the coil and the magnetic sensor.

Increasing the efficiency of the electromagnetic compensator is provided by the ratio of the magnetic moment M and the mass of the winding P of its coil, determined by the dependence

Where

M is the magnetic moment of the coil of the electromagnetic compensator;

P is the mass of the coil winding;

σ _max - the maximum permissible current density in the coil winding, not causing heating of the winding relative to the ambient temperature;

ρ _CR - the density of the material of the wire winding;

R is the maximum radius of the winding;

.r is the minimum radius of the winding, with respect

.

The main disadvantage of the prototype compass is the inability to expand the range of compensation for electromagnetic deviation caused by the magnetic fields of the electrical equipment of the vessel, ship, including demagnetizing windings and other equipment that generates and consumes direct current, as well as inter-instrument cable routes, without increasing the overall dimensions of the coils of the electromagnetic compensator , and therefore, the overall dimensions, weight and cost of the compass.

The main tasks to be solved by the present invention are aimed at providing the possibility of expanding the range of compensation for electromagnetic deviation while maintaining the overall dimensions of the compensator coils, and therefore the compass, while minimizing the compass heading error due to changes in the quarter deviation when sailing a ship or ship with a change in the breadth of navigation .

To solve these problems in a magnetic compass containing a magnetic sensor and an electromagnetic compensator, including coils mounted in pairs symmetrically relative to the vertical of the compass passing through the center of symmetry of the magnetic sensor, to increase the efficiency of the electromagnetic compensator by increasing the limits of compensation for deviation, while the magnetic axis coils are placed in planes passing through the compass vertical; the axis coinciding with the direction of the magnetic axis of the coil is inclined with respect to the line passing through the centers of symmetry of the coil and the magnetic sensing element by an angle defined by the formula

where α is the angle between the axis coinciding with the direction of the magnetic axis of the coil and the line connecting the centers of symmetry of the coil and the magnetic sensor;

Ψ is the angle between the vertical passing through the center of symmetry of the compensator coil and the line connecting the centers of symmetry of the coil and the magnetic sensor; electromagnetic compensator coils contain cylindrical cores made of a ferromagnetic low-coercive material with the same geometric dimensions and mass, while the centers of symmetry of the coil and core coincide at a common point; the distances between the centers of symmetry of the cores and the compass vertical are equal to each other, and the distances from the centers of symmetry of the cores to the center of symmetry of the magnetic sensor are also equal.

The proposed magnetic compass is presented in figures 1-3.

Figure 1 presents a General view of the compass with an electromagnetic compensator.

Figure 2 - placement of the coils of the electromagnetic compensator with cores.

Figure 3 - the main parameters of the coil with the core and its location.

The magnetic compass contains (Fig. 1) a magnetic sensing element 1 located in the pot 2, and an electromagnetic compensator 3, including two limit coils X 4 and two transverse coils U 5 (Fig. 2) with cylindrical cores made of ferromagnetic low-coercive material, respectively 6 and 7.

The positions of the coils with cores (FIGS. 2 and 3) are determined by the angles ψ measured from the vertical 8 passing through the combined centers of symmetry of the coil and core (point O of FIGS. 2 and 3) and the line 9 connecting the combined center of symmetry of the coil and core and the center of symmetry of the magnetic sensing element (point A of FIGS. 2 and 3), the magnetic axis of the coils being placed in planes passing through the vertical of the compass 10 and inclined relative to the lines connecting the combined centers of symmetry of the coils and cores O with the center of symmetry A magnet th sensing element, by an angle α.

Figure 3 presents the main parameters of the coils with cores:

T is the full induction vector of the magnetic field of the coil;

CMS - the center of symmetry of the magnetic sensitive compass (point A);

θ is the angle measured from the vertical 8 to the axis 11, which coincides with the direction of the magnetic axis of the coil;

α is the angle between the axis 11, coinciding with the direction of the magnetic axis of the coil, and line 9 connecting the centers of symmetry O of the coil with the core and the magnetic sensor A.

ψ is the angle between the vertical 8 passing through the combined center of symmetry of the coil and core, and line 9 connecting the centers of symmetry of the coil and core with the center of symmetry of the magnetic sensor;

φ is the angle between line 9 connecting the center of symmetry of the coil with the core (point O) and the center of symmetry of the magnetic sensor (point A), and the direction of the vector T;

l is half the length of the core;

r ₁ is the distance from the center of symmetry of the core (point O) to the center of symmetry of the magnetic sensing element (point A).

The proposed device operates as follows.

When direct current flows through the windings of the compensator coils, connected in series and according to, a magnetic field is created in the region of the magnetic sensitive element of the compass, the modulus of the induction vector of which is equal, and the vector itself is oppositely directed with respect to the field vector generated by the deviation source. Since the compensator coils are inclined at equal angles to the plane of the deck and are symmetrical, the total field vector of the coils is parallel to the plane of the deck. Due to the fact that the coils are inclined at an angle Ψ to the vertical, related to the angle α by relation (1), there are no vector projections perpendicular to the deck, field vectors T and their projections on this plane are maximum.

Cores made of low-coercive (soft-magnetic) material enhance the magnetic field induction in the region of the magnetic sensitive element of the compass, since they reduce the resistance to the magnetic flux generated by the current in the windings of the compensator coils, which expands the ability to compensate for the magnetic field induced by compass deviation sources.

If the sources are turned off and, as a result, the compensator coils are de-energized, magnetization by the field of the sensor element of the cores placed in the coils in the longitudinal plane of the compass at a 0 ° course, when the field vector of the sensor passes through these cores, does not deviate the sensor from the magnetic meridian plane , since the field vector caused by their magnetization also lies in the plane of the meridian. The magnetization of the cores placed in the coils in the transverse plane of the compass by the field of the sensitive element also does not cause deviation, since the cores are placed symmetrically relative to the longitudinal plane of the compass and the induction vectors created by their magnetization by the field of the sensitive element in the region of the sensitive element balance each other. At the 45 ° course, all four cores placed symmetrically with respect to the compass vertical line also do not cause deviation, since the cores create mutually balancing field vectors in the region of the sensing element created by their magnetization by the SE field. The same applies to all other courses, including intermediate between 0 ° and 45 °.

The present invention, compared with the prototype, provides a significant expansion of the compensation ranges of electromagnetic deviation, without causing the need to increase the number of ampere-turns of the coil windings, and also does not cause deviation due to magnetization of the cores, depending on changes in the induction (intensity) of the Earth’s magnetic field when sailing with a change latitude.

Theoretical supplement to the invention “Magnetic compass”

Cores of ferromagnetic low-coercive material placed inside the coils of the electromagnetic compensator are magnetized by the field of the magnetic sensing element of the compass (MCE), which causes a quarter deviation.

The coefficient of the quarter deviation, that is, its amplitude value when changing the course of the vessel, ship from 0 ° to 360 °, is determined by the formula (see Kozhukhov V.P., Voronov V.V., Grigoryev V.V. - L .: Sea transport , 1960 p. 196):

Where

D ₁ is the coefficient of quarter deviation;

and ₁ is the Poisson parameter, that is, the coefficient of proportionality between the field strength in the MCE region created by the cores located in the longitudinal plane of the compass and the magnetic field strength of the MCE magnetizing them;

e ₁ is the Poisson parameter, that is, the coefficient of proportionality between the field strength in the MCE region created by the cores located in the transverse plane of the compass and the MCE magnetizing field strength.

An obvious condition for minimizing D ₁ is the numerical equality of the parameters a ₁ and e ₁ with the same signs.

The expression for parameter a ₁ (see ibid., P. 190) has the form:

Where

- магнитная восприимчивость сердечника;

- magnetic susceptibility of the core;

V is the core volume;

l is half the length of the core;

r ₁ is the distance from the center of symmetry of the core to the center of symmetry of the MCE.

The expression for parameter e ₁ with the same core shape is identical to expression (2) for parameter a ₁ .

одинаково.With the same core material, the value

the same way.

With identical core sizes, the values of V and l are also the same.

Thus, the condition for the equality of the parameters a ₁ and e ₁ , which minimizes the value of D ₁ , is the symmetry of the arrangement of the cores relative to the MCE, at which the values of r are equal, which is reflected in the formula of the invention.

Literature

1. Nechaev P.A., Grigoriev V.V. Magnetic compass case. - M .: Transport, 1975, p. 89 (Fig. 64), p. 231-232.

2. Kozhukhov V.P., Voronov V.V., Grigoriev V.V. - L .: Maritime transport, 1960, pp. 196, 264-265.

Claims (1)

A magnetic compass containing a magnetic sensor element and an electromagnetic compensator including coils mounted pairwise symmetrically with respect to the vertical of the compass passing through the center of symmetry of the magnetic sensor element, thereby increasing the efficiency of the electromagnetic compensator by increasing the limits of compensation for deviation, while the magnetic axis of the coils are placed in planes, passing through the vertical compass; the axis coinciding with the direction of the magnetic axis of the coil is inclined with respect to the line passing through the centers of symmetry of the coil and the magnetic sensing element by an angle defined by the formula

where α is the angle between the axis coinciding with the direction of the magnetic axis of the coil and the line connecting the centers of symmetry of the coil and the magnetic sensor;
ψ is the angle between the vertical passing through the center of symmetry of the coil of the electromagnetic compensator, and the line connecting the centers of symmetry of the coil and the magnetic sensor,
characterized in that the coils of the electromagnetic compensator contain cylindrical cores of ferromagnetic low-coercive material with the same geometric dimensions and mass, while the centers of symmetry of the coil and core are aligned at a common point, the distances between the centers of symmetry of the cores and the vertical of the compass are equal to each other and the distances from the centers of symmetry cores to the center of symmetry of the magnetic sensing element are also equal.

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