Dynamic spiral motor animation.

[Dingus Mungus]

I was curious to see if you could model it and if the flux becomes completely "absorbed" into the keeper at that position, or "deflected" around the edges and not effecting objects behind it? or some kind of another arrangement that is self canceling?

Is the phenomenon effectively a magnetic gate? or a magnetic on/off switch so to speak?

I simulated the first deisgn I posted with a steel nail at the end of the iron bar and 99% of the flux is diverted straight to the oppisite pole in any position. Only a small ammount of flux is intoduced to the steel at the oppisite end. I am now doing extensive remodeling to see if I can find a way to use this as a magnetic gate, but outlook is poor currently. I will post any interesting results later.

TO ALL INTERESTED PARTIES:
http://femm.foster-miller.net/
Download a free copy of FEMM today!

If I get enough requests for a FEMM tutorial I will create a new thread with step by step instructions for modeling *BASIC* magnetic and electromagnetic simulations with attached demos. With more people searching the more we will find.

[Dingus Mungus]

The keeper has no poles when exactly in the neutral line

Here is the demo of the keeper moving from .25" away from poles to 2" away from poles.
I have also included zoomed in and amplified flux images to show the keeper's poles at 2".

[gyulasun]

Hi Dingus,

Thank you very much for your simulations.  The tendency of poles appearing at the keeper's endings as it is moved away gradually from the horseshoe magnet can be seen a little and it is enough performance from a free software. I wish a true 3D EM software were available for free...

Best Regards

Gyula