Thane Heins Perepiteia.

[gotoluc]

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[i_ron]

The difference between iron and steel is: when steel is magnetized it stays magnetized.
But iron only remains magnetized until the magnetic field is removed.
If the core of a transformer remains magnetic after the current is turned off that would resist the
transformer action. That is why it's important to get soft iron for the core.
Otherwise it's like winding a coil around a magnet.
My understanding for using welding rods to make cores is because they are a source of soft iron.
We can buy steel wire or rod for a lot less then the price of welding rods.

I noticed the rod chemistry on that site and it says E7014 rods have a low carbon content C 0.06.
I believe it's the carbon content that makes steel stay magnetized.
Anyone have any more info on this.
I though I seen someone else on this forum using welding rods, on another thread.

Abba, what you say is basically correct, but soft steel (sae 1010/1020) is somewhat like iron in that
it does not stay magnetized. It is hardened steel that retains it's magnetism for a long time.

I have used cast iron for cores which works well at low frequencies.

But to clarify (hopefully) the welding rod situation... the rods with names like E6011 are electric
arc welding rods and they come coated with a hard layer of flux. Also the sizes are generally fairly large. The rods that are usually specified for cores ie: Bedini machines, are OXYACETYLENE
welding rods of around 1/16th of an inch. I didn't see any on that site, perhaps a trip to a welding
supply store...?

Ron

PS: Thane, sorry about the use of capital letters there... it was slip, but I do live in a provincial
capital so must be able to use them on occasion? after all, we don't ALL live in THE capital and
get to use capital letters ALL the time.....lol

[aether22]

Back from holiday (it was nice but very happy to be back), and just got internet back too!

Ok, so I was wrong, there are 12 magnets on the rotor, but in only 6 positions.
I thought it was just the way they had been glued on, I only realized when I tried adding one of the extra magnets to the cupholders that they must be 2 deep! (it really wasn't apparent until then, not that I had long with it before going on my trip)

So I now have an 18 magnet rotor, nice!

So now I need to get the coil right, now I am yet to verify all this perfectly but with by .56mm dia wire it will take over 6Kg of wire or over 2km!  that's a seriously large amount of wire, I am questioning is Thane's coils are really that large?

I bought some 'bright' mild steel 1 inch dia. (approx)  bar which I will use as a core as soon as I can figure out how to wind wire on it.

But since a coil with the above specs with be very very extreme (using well over $100usd/cad of copper wire) I would like to get from Thane what is the resistance of the most minimal single coil you fully believe will work or has tested to work. (though I don't think you have tested 18 poles on 6 inch so I know it will be a guess)

I will try to exceed the minimum but hope to use less than 200 ohms of wire.

[aether22]

More on coils, first the ones above for instance do not look large enough to be 200 ohms, are they?

One thing is the huge difference between hoptoad's coils and Thanes which while it seemed he got a similar effect the number of turns could not be more different, hoptoads being very diminutive at only a few hundred turns where Thanes would seemingly have numbers in the 40,000 turns based on my calculations.

But then my calculations seem wrong, sure Thanes coils look large but I'm not sure they are as large as that in the videos and photos.

Ah more investigation and here's the answer.
I could not get AWG sizes in NZ, only metric here, and furthermore it is either criminally expensive or in overly expensive sizes.
So I pretty much got what was going, which was some .56mm dia wire (acceptable price and a weight I could JUST afford), where Thane used 26AWG I think which is .4039.

That seemed OK, .4 something .vs .5 something, not a big difference right? But it's a huge difference!

23AWG is the closest analog at .574mm as opposed to .56mm (.014mm  difference)
That would be  7.05KG to get to 200 ohms. (counting it as 23AWG)
I would need precisely 9849 ft (well as precise as I can get with a limit of 4 significant digits on the wiretronic calculator)

26AWG or .4039 is the wire Thanes used,
That's only 1.73KG to get to 200 Ohms, or 4875 ft

Less than half the weight and length of the wire that is only 0.1561mm  larger, under .16 of a mm, a very tiny difference or so it sounds!

So I am going to have to find some wire that is thinner, am I going to have to fight the temptation to buy stuff even thinner than Thanes to use less?


Thane, why do you use the gauge you do? Would you expect success with a lesser gauge?
Do you only use the gauge you do because it resists breaking?

Of course to some extent maybe I should aim for the same number of turns as Thane (or the same length), while my wire is fatter so I will use more wire getting to the same turns I shouldn't need double the length of wire I don't think (though may need to find a wire building calculator to make sure).

I am going to go out to pickup an optocoupler and use that for RPM measurements as using an aircore coil seemed to give imperfect results.

note: 1.73KG in red since I made an error first time.

[OUman]

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