Plastic pipe for coil?

[z.monkey]

Sure,
What is the composition of the welding rods?  Soft iron, or pig iron is best for soliciting magnetic flux from a coil.  I have built cores with rebar, and concrete reinforcing wires, not the ties.  Also I have used galvanized sheet metal, and galvanized steel pipes.  Soft iron just seems to work better but you have to be industrious to find it.  If you can get soft iron filings, like from an automotive machine shop, you can make a composite slug in any shape using the iron filings, epoxy, and a mold.  But I have found the pipes to be the most convenient and mechanically stable.  I have never worked with Bedini generator so I am not familiar with what is required there.  But, obviously, you want an efficient inductor.  I can tell you that you want to use a core material with the highest permeability you can get.  Get the coil wire in very close proximity to the core.  Make your windings as neat as possible.  There are also ways to cheat the windings to get more inductance, like bifilar winding and caduceus windings where the windings aid the electron spin in the other windings.  This is a very heady subject.  In a bifilar winding the electron spin of the every other winding is opposite.  One is going, two in coming, three is going, four is coming, and so forth.  This causes the electrons to accelerate because the electron spin in the adjacent wires in aiding rather than bucking the electron flow.  This gets a lot more complicated on the next layer because the windings are going in the other direction linearly.  What I have done to mitigate this is to wind one layer and terminate it.  Wind the next layer in the same linear direction then terminate it.  After the coil is finished I add jumpers around the outside of the coil to link the end of coil one to the start of coil two, and the end of coil two to the start of coil three, and so forth.  This way, even with multiple layers of windings, you can get all the windings to aid the spin of all their north, south, east and west neighbors.  Windings on the diagonals are bucking, but that is where the bucking effect is of least significance.  Caduceus windings are quite the opposite where the electron flows are purposely made to smash into each other.  A caduceus coil can be dangerous at high voltages and high frequencies because of unexpected results.  Theoretically, they can produce EMP effects with relatively low voltages (1000's of volts).

Recommended reading, The Awesome Life Force by Joseph H. Cater.

Have fun with this...

[raykos]

Hi Z. Monkey,

    OK, now you've done it!  It looks like you know your way around coils(feeble attempt at humor),
and since you do, I'll probably be bugging you with questions, if you don't mind?
   
     Lets take a scenario of where I would like to build a pulse motor.  The instructions call for winding a coil of 850 turns using 23 gauage wire on a spool that's 2.5" long with a 3/4" dia., and to use welding rods as the core.  OK, first problem, I don't have the spool or the welding rods, but I can go to Home Depot and get short pieces of black iron pipe, a bolt, a nut, & some fender washers to build the coil that you mentioned.  Should I get a piece of pipe the same size as the spool, or some other dimensions?  Then I have no clue as to whether or not to wind more or less or the same number of turns recommended, since I didn't use the spool method?  Is there some kind of formula, or any other way to find out the electromagnetic properties of  the "bolt method"  vs. the "spool method"?

     But, lets say I either make or find the proper spool, but can't find the proper welding rods.  However, I do have an electronics boneyard...that place in your house where old electronic equipment ends up because you just know your going to need a part...and there are old transformers & chokes with iron cores.  Suppose I were to take a special tool( 5 lb. hand sledge), cover the cores with a cloth and proceed to produce recycled iron pieces to use as core material in the spool.  Would that work?  And the question that comes to mind is, when I stuff those recycled pieces into the spool, must every little piece touch every other piece?  In other words if I poured epoxy or some other glue into the pieces, would the glue act as an insulator between the iron pieces?

    Considering the cost of wire these days,  I don't like the idea of maybe ending up with a coil that may be  just a few turns short, or way to big for the application.


Thanks,
Ray

[z.monkey]

Howdy Raykos,
The bottom line on building a coil is inductance.  Look up inductance in Wikipeda and look at the different formulas for calculating inductance.  This should give you some idea of how the physical form of the coil changes the way its inductance is calculated.  A radio coil is different from a solenoid, which is different from a transformer, which is different than toroid.  I think what you are trying to wind here is a solenoid.  I don't mean the electrically operated mechanical actuator kind of solenoid, even though the coil is similar.  This type of solenoid is a straight core with multiple layers of windings on it.

The form that you wind the coil on can be permanent, or it can be a fabrication form which is removed when the coil is finished.  I see coils build from wire spools, that's OK if that's the form you want.  A fabrication form can be anything because you are going to remove it before you put the coil on the core.  Wind the coil on the fabrication form, then "pot" the coil by pouring quick set epoxy into it.  Then remove the form.  This takes some practice to keep from getting epoxy all over the place. 

The magnetic lines of flux emanate from the end of the core.  In the case of the wire spool coil where the core is flush with the end of the coil the magnetic flux emanates from the end of the core.  In the case of the machine bolt the magnetic lines of flux emanate from the top of the hex head on the machine bolt.  What matters he is getting the end of the core as close as possible to the object that it is going to affect.  I think you are trying to make a Bedini wheel, right?  So in this case you object that you are trying to affect is on a spinning wheel.  You need to consider the centrifugal forces on the magnets around the edge of the wheel.  As the wheel spins faster it is going to stretch the magnets outward toward your coils.  If you don't have enough clearance there you magnets will smack into the coil and cause FMOD (Flying Metal Object Damage).  I have a little experience with this, see my Bicycle Wheel Alternator thread.
http://www.overunity.com/index.php/topic,4135.0.html

Yes you can build cores out of junk or scrap.  But you will make a far better inductor if your core is uniform.  You can make a ferrous slug out of iron filings and epoxy.  Scrap chunks don't work as well.  It is better to start with fresh material and build the core by design rather than happenstance.  Many off the shelf nails are soft iron, are in the right form, and are cheap.  All you have to do is cut the points and heads off with a hacksaw and you have rods.  Welding rods are an option, but they have other materials in them, and they are not cheap.  You can get sheet metal, cut it into thin strips, and form them into a bundle.  Take a galvanized steel pipe, fill it with iron filings, and put caps on the ends.  I use machine bolts, and iron tubes.  You could make a slug of iron filings and glue plastic ends on it.

One other thing, iron is malleable.  You can't break it by hitting it, you have to cut it.  But you can take a chunk of iron, like a scrap rail road track piece, and produce iron filings by drilling holes in it.  The 1/2 inch ID cores on my Soft Particle Reactor had to be machined to get the machine screws through them.  This produced a significant quantity of iron filings.  This is blacksmith work, definitely not easy, but worth it because you will build up your muscles, and chix dig that.

About the wire, find a surplus electronics shop, a lot of times they will have stuff they bought at auction and it will be a lot cheaper than retail.  Don't buy stuff at Radio Shack...

Blessed Be Brother...

[raykos]

Hi Z.Monkey,

   Just received your response and will be reading and thinking about what you wrote.  But, before that I did check out your "motornater",  and I must say,  that is really neat!  As soon as I learn more than I presently know, (which at the moment isn't a lot!), I hopefully will be trying something like that...way to go Z!

Ray

[raykos]

Hi again Z. Monkey,

   If I may,  what is your opinion of soldering coil wires?  What I'm wondering about is if I end up with two spools of wire with 'x' amount of feet left on them , and if I soldered them together I would have enough to make another coil, can I do this?  Let me also say I know a little bit about soldering & using heat shrink tubing, so I think I can make a solder joint that won't look like snake that just ate a large meal.

Thanks,
Ray