Re: [femm] Worked example needed

[dcm3c@xxxxxxx]

In a message dated 9/4/01 11:03:57 PM Eastern Daylight Time, 
jim.bloor@xxxxxxxxxxxxxxxxxxxx writes:


> I have two problems.  Can anybody supply a worked example of a simple 
> multilayer coil wound on a steel core.  I would like to work out the 
> inductance.  I have modelled the coil and calculated the inductance 
> using the E and I values but I get an answer which is 1 million times 
> too small.  I am obviously doing something silly here.  Since this is 
> a basic problem I'm sure somebody can put me right.


I've put an example problem for computing inductance at:
http://members.aol.com/_ht_a/gmagnetics/Inductance-Example/Inductance-Example.

htm
Another nice inductance example is on Jim's website at:
http://web2.iadfw.net/jd4usa/guncoil5.htm

> The second problem is how to get axisymmetric models to calculate.  
> No matter how I draw the model, I get an error message when I press 
> the calculate button.  Once again I am sure this is s trivial problem 
> but there is no information in the manual to help.


Make sure that you don't have anything drawn at a radius of less than 
zero--otherwise, you will get a cryptic error message about not being able to 
solve the problem.  I should change this message to be more informative....  
As an example of an axisymmetric problem, check out Example 2 at 
http://members.aol.com/_ht_a/gmagnetics/tutor/tutor.htm

> Anyway - Femm is brilliant and I look forward to learning how to use 
> it more effectively.
>
> Regards
>
> Jim Bloor