Electromagnet Question

[gyulasun]

  I'd like to see a similar setup that allowed the solenoid to to be energized for longer.  I don't see this as being easily possible with a mechanical set up and instead would require a variable rate switching circuit.  Again, I'm not sure what this would accomplish, but now I'm just playing while trying to think where the current drop effect could possibly be useful.

Hi Mondrasek,

The monostable circuits I referred to earlier would serve you as variable rate switching circuits ( http://www.overunity.com/index.php/topic,5279.msg119307.html#msg119307 ).

This way you could nicely approach the different L/R time values, adjusting shorter, similar or longer times to see the effect on the current shape.

rgds,  Gyula

[mondrasek]

I was hoping to avoid making solenoids but it looks like I'll have to in order to investigate some ideas further.  Where is the best place to get magnet wire on the net, especially with different color enamel in case I need to do bifilar ones?

[gyulasun]

Maybe on ebay the cheapest? 

http://business.listings.ebay.com/Wire-Cable_Magnet_W0QQsacatZ100180QQsocmdZListingItemList

http://stores.ebay.co.uk/Brocotts_Winding-Wire_W0QQcolZ4QQdirZ1QQfsubZ11474544QQftidZ2QQtZkm

http://cgi.ebay.com/eBayISAPI.dll?ViewItem&item=160268215204

rgds,  Gyula

[capthook]

I've ordered wire numerous times from both of these:

http://www.bulkwire.com/

http://stores.ebay.com/swords-science-treasures

[mondrasek]

Thanks again guys.  Magnet wire is on order.

I plan on testing some solenoid wrap configurations for my own knowledge.  But also, I am particualrly interested in wrapping a very long solenoid.  I want to see what happens to my previous test arrangement where I fire a permanent magnet from inside a long solenoid using repulsive magnetic fields.  From what I have tested earlier the current draw of the solenoid decreased as the PM accelerated.  If the solenoid was infinite in length, how far would the current draw drop?

All ideas and suggestions welcome!

M.