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Tutorial 3.0

   Circumferentially magnetized multipolar magnet with six Poles

This tutorial shows the basic handling of the software as well as its basic characteristics. The problem which shall be teated here consists of a cylinder made of  six homogenous segments of anisotropic ferrite, having a  remanence induction of  0.40T each. The example below and similar problems ca be treated by use of the demo version of PS-PERMAG and for sure by the full versions 3.0 and 3.1. The additional features of both versions which are not shown here can also be learned easily by use of their extensive help system. The treatment of the new two pole sensormagnets of version 3.1 with enhanced geometric details can be studied in Tutorial 3.1

After starting PS-PERMAG a 3D model of an illustrative permanent magnt shows up on the screen. To define the above described magnet please click on the M symbol at the top symbol bar. M stands for circumferentially  magnetized multipolar cylinders with homogenous magnetization in each pole, see below This opens an input dialog for the data input. Here the basic data of the magnet are given in. Background for defining a cylindrical magnet  is always  a cylindrical coordinate system, see drawing above. This means e.g. that at half the axial height of the magnet there is always z=0. At zero angle phi=0 there always starts an outward oriented pole.

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After you have pressed OK the respective new 3D model below shows up on the screen including the defined results path. You can zoom in or out of the model by using your mouse central wheel. By a left mouse click and simultaneous mouse movement one can turn the model around its x- or y-coordinate axis. By a right click together with a  mouse movement the model can be moved horizontally or vertically. Simultaneous left click and use of the shift key on your keyboard will let you turn the assembly around the z-axis. A general method to increase or decrease the screen contents may also be the use of the + or - button in the second symbol bar. By pressing one of them them beside 3D models all other contents of the screen can be changed by size. With the help of the neighbored SO symbol the respective zoom factors for texts and diagrams can be stored as defaults for any new calculations. By this it is possible to adjust the software to the users screen resolution. The coordinate system symbol you can switch on and off by the respective button in the second symbol bar. Please push now the GO-button to start the field calculations. After a few seconds they should be completed. The progress will be shown by a respective progress bar. Please push then the button to show a diagram for the results of the radial field component as indicated in the picture below by the arrow. The button the show the letters r and x. The three neighbored buttons to the right stand for the other two field components as well as for the absolute field value.

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Now look onto your first results. These are the values of the radial field component as a function of the circular angle. Instead of using the full angular range it can be cut to a defined interval. To change the diagram please click on the respective button on the left side of the second row of symbols, see the picture below. By this an input dialog will open to let you change the start and stop angle. In case you want to return from the field diagram back to the 3D magnet model, please click the respective button in the right half of the second symbol bar. Right beside this button (Here in grey) are three option buttons for the 3D model (Hide coordinate triangle, Transparent magnet model, Default position).

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The fields can also be watched by numerical listings, which can be opened by clicking on the respective  brightly gray buttons in the first symbol bar. The first of these buttons opens the listing of the radial component when cylindrical result coordinates are used. For systems needing cartesian coordinates this button shows the x-component. Generally for cylindrical magnets by default a cylindrical coordinate systems for the resulting components is adjusted. But for all kinds of magnets also cartesian coordinates can be chosen for the output. By clicking the button with the two doted lines in the options bar (second symbol bar) one can change the total number of values which PS-PERMAG computes on a chosen path. To finalize such change the computation has to be repeated by using the GO button. 

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Click on the picture to zoom in !

Additional calculations based on the single field components are e.g.  Fourier series expansions. In case you would like to have an overview over the approximation of e.g. the radial field by such series, please click in the third bar (evaluation bar) and there on the first of the gray symbols in the last quad. Then the original curve together with its Fourier approximations up to specified grades are graphed. Below this is shown for the first two poles  after having constricted the geometric diagram angle to 180deg. Which and how many grades are chosen for graphical depiction can be determined by clicking the first button of the second symbol bar. A listing of all numerical coefficients of the  Fourier series can be shown for each single field component  by clicking on the respective button with letter c in the third symbol bar, like shown below by the respective arrow. In addition the distribution of different wave orders can also be shown graphically by clicking the respective button in the second last  quad of  the third row of  symbols.

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Another sort of evaluations are field angles which are of importance e.g. in sensor technology. In the evaluation bar (third row)  a click on the respective button of the second triplet  reveals these angles graphically. Below the angle of the field projection in the r-phi plane is shown. The buttons of the first triplet supply the respective numerical listings of these angles.  All angles are defined between -180deg and +180deg. Graph colours can be chosen generally in the options bar as being shown by the respective button and its dialog mask below.

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For field evaluation beside circular paths for all kinds of magnets also straight lined paths can be defined. In addition all results on all sorts of paths can be put out in cylindrical as well as in cartesian coordinates. In the picture below the  respective buttons for the change of path geometry and also for the choice of result coordinates are marked by respective arrows. By choosing the button for defining a magnet after having switched to a linear path, an input dialog as shown below will open. To get to the 3D model as show below again the switching button in the second symbol bar is to be used. The linear path is show by a green line. In the case below the linear path shall run 1mm above the center of the first pole, starting at a radius of 12mm and ending at 24mm. Due to the input dialog linear paths are always defined by their cartesian coordinates of start and end point location. Because the center of the first pole is located at 30° here, and as the axial length of the magnet is defined as hm=6mm, the following coordinates for the start point location have to be put in: x=12*cos(30)=10.392, y=12*sin(30)=6.0,z=hm/2+1=4.0. The respective figures for the end of the linear path are: x=24*cos(30)=20.785, y=24*sin(30)=12.0, z=hm/2+1=4.0. After finishing the input dialog the computation has to be started by use of the Go button.

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In the next screenshot we show the result of the x component of the field after a problem definition on a linear path like in the picture above. The result coordinate system has been switched to cartesian coordinates here. Because we have a straight line path the results are shown as a function of distance.

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Click on the picture to zoom in !

To close this tutorial some additional features should be mentioned: In the first symbol bar a dialog can be chosen to put in a description of the analysis. The current contents of the screen can be copied to memory to be used in other software, e.g. to be placed into reports or presentations. This can be done by clicking the camera button in the upper symbol bar. Beside the common binary storage of the analysis, which does not only include all primary and secondary results but also the most current user adjustments of  the software, in addition an ASCII  storage of the fields by using the “txt” button can be performed. Another button of importance is the red button close to the “Go” symbol, which lets you stop a current computation. The options bar, in addition to its already mentioned features, also supplies features like changing the accuracy of computation or giving in and storing your personal data, which will then always be shown on the detailed printouts of PS-PERMAG. The size of the screen view can be adjusted to your demands using the + and - buttons. Additionally a specific button in the options bar opens a dialog which lets you adjust subjects like the thickness of letters or diagram curves or the visibility of diagram grids.  Three sorts of  option buttons handle the storage and recover of the user adjustments of the software. Not to forget: All  features, which are usable by the above described buttons, can also be used by clicking on their respective menu commands, which are included into the main menu bar on top of the program window. Additional features of the software can be learned easily by use of its extensive help system.