JPH0786510B2 - Moving coil type instrument - Google Patents

Description

TECHNICAL FIELD The present invention relates to a moving coil instrument, and more particularly to a moving coil instrument having improved scale characteristics.

{Background of the Invention} In order to improve the scale characteristics of a moving coil instrument, A. regulation of the directionality of magnets B. effective placement of pole pieces C. improvement of machining accuracy of parts etc. can be mentioned. Even if the instrument is configured with these points in mind, the tracking error will be about ± 1.5%.

{Problems to be Solved by the Invention} The present invention has been made in order to solve the above problems in a moving coil instrument, and its purpose is to improve a magnetizing means for magnetizing a permanent magnet. Therefore, it is an object of the present invention to provide a moving coil type instrument capable of keeping a tracking error within ± 0.2%.

{Means for Solving the Problems} In order to achieve the above-mentioned object, the present invention uses data analysis of virgin scale characteristics of an instrument in which a DC power source whose output voltage is variable is connected to a moving coil, and is used for the instrument. And a computer for determining the magnetic characteristics of the permanent magnets, which are wound around a plurality of magnetic poles annularly arranged around the permanent magnets based on the data analyzed by the computer, and connected to the computer via a controller. And a magnetizer that remagnetizes the permanent magnet by changing the level of magnetic flux by a magnetizing coil, and the permanent magnet remagnetized by the magnetizer is configured as an internal unit of the instrument. . Hereinafter, examples will be described in detail with reference to the drawings.

{Embodiment} FIG. 1 is a configuration diagram of an embodiment of a magnetizing device for attaching and detaching an exciting part of an instrument according to the present invention. In the figure, 10 is a computer, 11 is its keyboard, 20 is a controller controlled by the computer 10, 21-24 are pulse amplifiers, 31
˜34 are magnetizing coils respectively. The output terminals of the controller 20 are connected to the magnetizing coils 31 to 34 via amplifiers, respectively. The magnetizing coils 31 to 34 are wound around the magnetic poles of a magnetizer 40 having four magnetic poles 41 to 44 arranged annularly as shown in FIG.

50 is an internal unit of the moving coil type instrument. This internal unit includes an exciting portion (exciting portion for an internal magnet type instrument) including a cylindrical core 53 arranged in a permanent magnet 51 with a gap 52, a movable coil 54 attached to the exciting portion, and the movable portion. It consists of a pointer 55 attached to the coil, and the permanent magnet 51 is magnetized in advance with a predetermined directionality. Reference numeral 56 shown in FIG. 1 is a variable DC power supply for supplying a current to the movable coil 54. The inner unit 50 of the meter is arranged inside the magnetic poles 41 to 44 of the magnetizer 40 in a predetermined direction and at a predetermined position. The inner unit 50 is already magnetized as described above. In this case, the tracking error of the instrument due to virgin magnetization is about ± 3% even if measures are taken in the magnetization direction.

In such a configuration, a current is supplied from the DC power supply 56 to the moving coil 52 to rotate the moving coil. The movable coil 52 rotates according to the supplied current and the virgin magnetization characteristic of the magnet 51. The computer 10 obtains linearity by image-processing the deflection angle of the movable coil 52 with respect to the applied current value, and the computer 10 controls the magnetizing current supplied to the magnetizing coils 31 to 34 in accordance with the linearity. That is, by supplying a magnetizing current to the magnetizing coils 31 to 34, the magnetic flux from the magnetic poles 41 to 42 is changed to φ12,
When the magnetic flux from the magnetic poles 42 to 43 is φ23, ..., The magnetic fluxes φ13 and φ24 interlink the permanent magnet 51 as shown by the chain line in FIG. Therefore, the computer 10 according to the virgin linearity
If the magnetizing currents supplied to the magnetizing coils 31 to 34 are controlled for each coil by means of, the permanent magnets 51 are linked to each other between the deflection angle of the movable coil 52 of zero and the full scale FS as shown in FIG. The magnetic fluxes φ13 and φ24
As a result, the magnetic distribution of the permanent magnet 51 becomes the target value, and the linearity is improved. According to the experimental results of the present invention, the tracking error can be greatly improved,
Could be within%. The magnetizing current for changing the magnetic distribution has been described in the above embodiment in the case where the magnitude of the current is changed. However, the magnetizing current is a pulse current,
The pulse width may be changed.

{Effect of the present invention} As described above, in the present invention, the magnetic characteristic of the magnet used in the instrument is analyzed from the scale characteristic of the instrument using a computer, and the magnet is used based on the analyzed data. Since it is configured to re-magnetize, it is possible to easily obtain a moving coil instrument capable of keeping the tracking error within ± 0.2%.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a magnetizing device for magnetizing an exciting part of an instrument according to the present invention, and FIG. 2 is a block diagram of a magnetizer used in the device of FIG. 1, FIG. 3 and FIG. The figure is an illustration of the magnetization characteristics of the magnet when magnetized using the apparatus of FIG. 10: Computer, 31-34 ... Magnetizing coil, 40 ... Magnetizer, 41-44 ... Magnetic pole, 50 ... Internal unit, 51 ... Permanent magnet,
54 ... Moving coil.

Claims (1)

[Claims] 1. A computer for analyzing data of virgin scale characteristics of an instrument in which a direct-current power source having a variable output voltage is connected to a moving coil to obtain magnetic characteristics of a permanent magnet used in the instrument, and a computer for analyzing the magnetic characteristics. Based on the data obtained, the magnetic flux levels are varied by magnetizing coils that are respectively wound around a plurality of magnetic poles that are annularly arranged around the permanent magnet and that are connected to the computer through a controller, and then the permanent magnet is regenerated. It has a magnetizer that magnetizes,
A movable coil type instrument characterized in that the permanent magnet remagnetized by the magnetizer is configured as an inner unit of the instrument.