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simple_magnetic_simulation_in_femm_-_step-by-step_tutorial [2021/05/11 19:39]
stanzurek [Step 2 - problem] 		simple_magnetic_simulation_in_femm_-_step-by-step_tutorial [2022/06/01 10:13] (current)
stanzurek [Step 1 - solver]
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 Open FEMM and start new problem, '' menu > File > New ''. Open FEMM and start new problem, '' menu > File > New ''.
  
-Select ''Magnetics problem''' from the pop-up window (Fig. 1).+Select ''Magnetics problem'' from the pop-up window (Fig. 1).
  
 {{select_problem.png}} Fig. 1. Select problem {{select_problem.png}} Fig. 1. Select problem
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 {{enter_point.png}} Fig. 3-2. Entering point with coordinates (0,0) {{enter_point.png}} Fig. 3-2. Entering point with coordinates (0,0)
  
-Click on the ''Zoom extents'' button (Fig. 3-3), which is the third one (white rectangle with a magnifying glass). (//If not sure - hover a mouse over the buttons and see their description in the botoom left of the FEMM window.//) +Click on the ''Zoom extents'' button (Fig. 3-3), which is the third one (white rectangle with a magnifying glass). (//If not sure - hover a mouse over the buttons and see their description in the bottom left of the FEMM window.//) 
  
 Then click on the ''Zoom out'' button once (magnifying glass with a minus). Then click on the ''Zoom out'' button once (magnifying glass with a minus).
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 Select the "Arc" button (//Operate on arc segments//) (see also Fig. 3-1).  Select the "Arc" button (//Operate on arc segments//) (see also Fig. 3-1). 
  
-The arcs are always drawn in anti-clickwise direction. So to draw a bottom arc as shown in Fig. 5-1 the points have to be clicked in the sequence "1" then "2". To draw the top arc click "2" then "1".+The arcs are always drawn in anti-clockwise direction. So to draw a bottom arc as shown in Fig. 5-1 the points have to be clicked in the sequence "1" then "2". To draw the top arc click "2" then "1".
  
 {{arc_drawn.png?500}} Fig. 5-1. Bottom arc from 1 to 2, top arc from 2 to 1 {{arc_drawn.png?500}} Fig. 5-1. Bottom arc from 1 to 2, top arc from 2 to 1
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 FEMM contains a library / database of materials, which can be used in the model, Fig. 9-1. FEMM contains a library / database of materials, which can be used in the model, Fig. 9-1.
  
-{{material_library.png?500}} Fig. 9-1. Acessing Materials Library+{{material_library.png?500}} Fig. 9-1. Accessing Materials Library
  
  
-The library window has two parts. On the left ("database" in Fig. 8-2), there are all the available materials as provided by FEMM. New materials can be added ot it if needed.+The library window has two parts. On the left ("database" in Fig. 9-2), there are all the available materials as provided by FEMM. New materials can be added to it if needed.
  
 The part on the right is for all the materials which will be accessible within the given model. Simply use the mouse to drag-and-drop method to drag the given material from the left to the right sub-window.  The part on the right is for all the materials which will be accessible within the given model. Simply use the mouse to drag-and-drop method to drag the given material from the left to the right sub-window. 
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 FEM equations require boundary conditions to be solved. They act as a reference point. Many different conditions can be specified, but for a simple magnetics simulation it is typically most useful to use the built-in "open boundary" feature. This boundary simulates an infinitely large volume (hence "open"), even though it can be positioned quite close to the simulated objects. FEM equations require boundary conditions to be solved. They act as a reference point. Many different conditions can be specified, but for a simple magnetics simulation it is typically most useful to use the built-in "open boundary" feature. This boundary simulates an infinitely large volume (hence "open"), even though it can be positioned quite close to the simulated objects.
  
-This "open boundary" method (Fig. 10-1) should be done only afer all other geometry was created, because it can automatically set the right size of the boundary, suitably larger thatn the rest of the model. If this is the case then nothing needs to be changed in the pop-up window, and all the default values can be accepted with "OK".+This "open boundary" method (Fig. 10-1) should be done only after all other geometry was created, because it can automatically set the right size of the boundary, suitably larger than the rest of the model. If this is the case then nothing needs to be changed in the pop-up window, and all the default values can be accepted with "OK".
  
 {{open_boundary.png?500}} Fig. 10-1. Create open boundary automatically {{open_boundary.png?500}} Fig. 10-1. Create open boundary automatically
  
-After accepting there will be many cirles created automatically, Fig. 10-2. There will be some block names appearing in the circles (as shown by the red arrows). These should be ignored, because they are needed for correct operation of the boundary.+After accepting there will be many circles created automatically, Fig. 10-2. There will be some block names appearing in the circles (as shown by the red arrows). These should be ignored, because they are needed for correct operation of the boundary.
  
 {{open_boundary2.png?500}} Fig. 10-2. Open boundary created {{open_boundary2.png?500}} Fig. 10-2. Open boundary created
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 ==== Step 11 - block labels, materials, currents ==== ==== Step 11 - block labels, materials, currents ====
  
-Every part in the model must have a material data assigned to it, so FEMM know how to solve it. Each area completely surrounded by blue lines or arcs represtents a "block", and each such block has to have the material specified for it. This is done by using the gren icon //Operate on block labels//, Fig. 11-1.+Every part in the model must have a material data assigned to it, so FEMM know how to solve it. Each area completely surrounded by blue lines or arcs represents a "block", and each such block has to have the material specified for it. This is done by using the green icon //Operate on block labels//, Fig. 11-1.
  
-After selecting the option click somewhere (anywhere) inside of each block, as shown in Fig. 11-1. A green point called ''<none>'' will appear with each click. To remove it, just right-click on it (to select it, changes colour to red) and press Delete (on keboard).+After selecting the option click somewhere (anywhere) inside of each block, as shown in Fig. 11-1. A green point called ''<none>'' will appear with each click. To remove it, just right-click on it (to select it, changes colour to red) and press Delete (on keyboard).
  
 {{block_labels.png?500}} Fig. 11-1. Add block points {{block_labels.png?500}} Fig. 11-1. Add block points
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 Analysis is executed by clicking the "cranked cog" icon (red arrow in Fig. 13-1). A pop-up window appears which shows the progress of calculations. Just wait until it finishes. No message is shown if all finishes correctly.  Analysis is executed by clicking the "cranked cog" icon (red arrow in Fig. 13-1). A pop-up window appears which shows the progress of calculations. Just wait until it finishes. No message is shown if all finishes correctly. 
  
-As soon as the small window dissapears the results can be viewed by clicking the "glasses" button (black arrow).+As soon as the small window disappears the results can be viewed by clicking the "glasses" button (black arrow).
  
  
-For all-linear models the calculation finishes in one step. For non-linear models it takes many iterations. For highly non-linear models (e.g. with deep saturation) or with large very dense mesh, the calculatiations can take very long time. +For all-linear models the calculation finishes in one step. For non-linear models it takes many iterations. For highly non-linear models (e.g. with deep saturation) or with large very dense mesh, the calculations can take very long time. 
  
-If there are errors in the model or material data the solution might not converge. If the computation time is exessive typically there is a problem somewhere in the model (block labels, double labels, wrong boundary, etc.)+If there are errors in the model or material data the solution might not converge. If the computation time is excessive typically there is a problem somewhere in the model (block labels, double labels, wrong boundary, etc.)
  
 {{analyse.png?500}} Fig. 13-1. Analyse / solve {{analyse.png?500}} Fig. 13-1. Analyse / solve
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 {{solution1.png?500}} Fig. 14-1. Results window, with field lines, no colour map {{solution1.png?500}} Fig. 14-1. Results window, with field lines, no colour map
  
-Clicking the "rainbow" button shows the small window, which which the type of variable can be selected: Flux density B, Magnetic field intensity H, or Current density J. Limits are scaled automaticaly betwen the min. and max. value present in the model, but they can be adjusted manually as needed, Fig. 14-2.+Clicking the "rainbow" button shows the small window, which which the type of variable can be selected: Flux density B, Magnetic field intensity H, or Current density J. Limits are scaled automatically between the min. and max. value present in the model, but they can be adjusted manually as needed, Fig. 14-2.
  
 Don't forget to tick the "Show Density Plot" box! Don't forget to tick the "Show Density Plot" box!
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 ==== Step 15 - plot data along line ==== ==== Step 15 - plot data along line ====
  
-In the solution window, use the "red line" icon (Fig. 15-1) to draw a path of lines or arcs, between any two existing points (left-click of mouse) or between any arbitrary points (righ-click of mouse). Once the path is created, various values can be plotter along that line, from the beginning to its end, in the same order as it was drawn.+In the solution window, use the "red line" icon (Fig. 15-1) to draw a path of lines or arcs, between any two existing points (left-click of mouse) or between any arbitrary points (right-click of mouse). Once the path is created, various values can be plotter along that line, from the beginning to its end, in the same order as it was drawn.
  
 The path can end at the same point it started. The path can end at the same point it started.
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 ==== Step 17 - conductor info ==== ==== Step 17 - conductor info ====
  
-The losses in the ciruict (energised coil) can be integrated with the block method described above, but much reacher information is provided with the "Circuit properties" icon, Fig. 17-1. +The losses in the circuit (energised coil) can be integrated with the block method described above, but much richer information is provided with the "Circuit properties" icon, Fig. 17-1. 
  
 If there is more than one current/circuit defined then it can be selected from the drop-down list. If there is more than one current/circuit defined then it can be selected from the drop-down list.
simple_magnetic_simulation_in_femm_-_step-by-step_tutorial.1620754757.txt.gz ยท Last modified: 2021/05/11 19:39 by stanzurek

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