@ Cap, Jeanna
The speed at which the core loses it's magnetism is more affected by the type of material it is composed of. It is referred to as the core's "permeability".

The intensity of the magnetic field is affected by the power applied to the primary (self-generated in our case) and by the speed at which the contact is broken in the make/break circuit and the frequency of the make/break cycle.


I finished the wire length calculator spreadsheet. It's attached. The only thing you need to enter is the wire diameter, the core diameter and the coil length. The length is calculated for up to 30 layers, so it could be useful for knowing how much wire to buy for your secondary, also.

I just want to report this little thing I did today using the iron stake.


I used my scope and touched the wires and got a 4mV to 16mV  spike briefly on the coil. It was something but very little.

Even though the stake should be able to demagnetize itself, after a couple of touches I had to touch the opposite wire to get the same reaction. this means to me that there is too much remanence left.

@Hoverdj,
Here is the thing
In the high permeability toroids I have been using with the joule thief circuits, the spike must be very sharp for a high voltage to occur.

Yes, It is raised with a higher input voltage, but a slow rise or slow decline will never make the high spike and high frequency I think we need.
[edit
I guess I mean when the break happens it needs to be a sharp break too and if the core cannot drop the magnetization it got from the on side of the cycle, it won't make a very good spike.]

That is why I believe the softest iron we can find will be the best for us. Or a ferrite, but where? I got a 4 inch long ferrite stick from cws , but 4 inches is a little short for this, maybe....

I don't have any problem with others trying things but I already tried so many things, I will only make another coil when I have put together what I think should work,

so carry on!

jeanna

edit:
WOW 1800 feet of wire!

Jeanna, I think we're saying the same thing. Or at least trying to.

What I meant by intensity is how far from the core the magnetic flux reaches. But speed is definitely the key...to a point. You will eventually reach a point where the magnetic flux is moving so fast that the core doesn't have time to recover. Thus, we say that the core has become saturated. This can also be true going the other way - the flux doesn't have time to reach the outside of the secondary (because it's too fat).

"WOW 1800 feet of wire!"
Yeah...I only did 8 layers. My hands are still aching!

@ IotaYodi,

Quote from: IotaYodi on April 27, 2010, 01:55:14 PM
Have any fluorescent lights? That would do it. Natural electrostatics in the air can build Mv but not as quick as a fluorescent ballast. The polarity may have changed if you moved the coil in a different orientation to the Earths magnetic field or an external field like house wiring or something magnetic.

The timing of the total field collapse may be able to be "tuned" to a faster rate using ferrite instead of iron.

Yes, I remember now, I had my soldering iron turned on, it was about 12" to the coil, and the overhead light globe on its stand, about 15" from the coil. I turned off the soldering iron and the coil settled down a bit, I turned off the light and it's "tiny output" went different, but when I had my scope connected to the ends of the copper and Iron wires, it showed a larger sine wave, but there was no pulse actions or spikes. The glass reed switch is broken because of excessive heat from soldering it so I have to put another one there, but that's later on.

I went for a walk around the house holding the Digital Meter, that's when I noticed the + to - mv output.


In my opinion I simply haven't enough bifilar turns on this coil, I used up all the copper wire I had of that size so I will have to find another lot before I try this again.

OK on the iron to ferrite as the magnetic medium, I was thinking it would work, if you fed the output into an UPS across a 24volt battery, then one could then power the UPS continuously, as long as the charge rate from the stubblefield coil could keep up with the MAX load drawn by the UPS, then free power for the life of the equipment.
The UPS keeps handling the usual voltage/Frequency/Load, the stubblefield coil takes care of the deliverance of the power to the Battery/UPS.

 
@ Jeanna,

I have designed this stubblefield coil as a "dry" coil, because I needed to see for myself what this type of coil would do, the layers of insulation is just masking tape, which won't allow moisture to permeate through the coils, anyway the insulation on the iron coils is not cotton, it is just the type of covering that one sees on ordinary tiewire, but it is flat green in colour.

The bolt I used is what we call in Australia a "threw" bolt, it is just a long bit of threaded steel rod, I placed a 1/2" plastic electrical conduit between the wooden disk ends, the 2 steel nuts hold it all together.

I noticed something very unusual while I was winding the coils outside, the mossies seem to want to head directly for the bolt ends of the coil, they left the coils and the wooden ends alone, didn't want anything to do with them, just the bolt ends, so can mossies sense some type of magnetic field? could be.


Anyway, I am going to try something that Protonmom mentioned to me a while ago, put some iron wire in a container and set it alight, to anneal it, but I will do the same with copper and  that's the way to get rid of the varnish, so I will be able to get unsulated copper wire, then I can use that to wind with.
-------------------------


I learnt 3 things from this, Blisters,difficulty in coil winding, and not having enough wire in a single full length.

I have blisters on both my hands from holding it all together while I was winding it.
Next is a Stubblefield Coil winder on the agenda, and a meat grinder might be the best way to begin this as everyone could buy this item, just a small modification to it and it should work OK.

I had 4 separate lengths of same size copper wire, as the last of each wire end appeared, I made a 90 degree turn, and ran the wire towards the wooden end, drilled a single hole through the end, fed the wire end through the hole. Grabbed another copper wire end and fed that also through the same hole and fed it back along the top of the coil back to where the original 90 degree end was, but made a 90 degree end on the "2nd" copper wire and continued to wind in the same direction as before. I insulated the 2 wires running towards the wood end, the newer turns covering and holding those wires down. The free ends I eventually soldered together outside the coil, they are connected to nothing else. I had to do this 3 times.

Just in case anyone was curious about how I did this.

@ Lasersaber,

Please put a small power transformer across the output from your stubblefield coil and let me know how it went
(a) can you charge a usual run of the mill cap with it?
(b) can you see any impulses in your coils output?
(c) can you light a 1.5v torch bulb with it?
(d) can you rectify the output using 1 diode or a bridge diode?

     
jim

2549 = 1st coil layer is done

2550 = On the way back during coil layer 2

2559 = The end of the 1st copper wire, I put a 90 degree angle and drilled a hole into the wooden disk, the wire end is poked through the hole.

2560 = The end of the next copper wire is fed through the same hole the wires are then twisted together. the copper wire has a 90 degree turn where it wil continue to become a coil, the 2 leads have a single tape layer as insulation.

2562 = 3 different copper wires are now joined in a series with each other making just 1 long copper wire which is wound next to the iron wire in bifilar fashion.
 

@ Cap-Z-ro,

Quote from: Cap-Z-ro on April 27, 2010, 06:33:38 PM
A though occurred, so I thought I'd pass it on in case it matters.

Could it be that the length of time the iron takes to lose its magnetism is related to voltage-ampherage ?

Regards...

No, Voltage and Amperage is related to the size wire used, amount of turns on the coil, the intensity of the magnetic field, and it depends on the type of iron used.
Skimping on any item will lower the output of the coil.

So the iron bolt either absorbs more or less magnetic lines of flux, if we look at an ordinary E iron transformer, it has thin sheets of E iron especially made to absorb more magnetic flux.
If the iron bolt loses its magnetism slowly, it will cripple the output of the coil.