Stubblefield coils (bifilar) and speculations

[jeanna]

Jeanna


I  think what   the  image shows is   what is called  ring down
 can  you  post the  URL for it ?


gary   

here is the calculator page. see you in a week. the whole site is fun,

but please first, tell me again , what do you think?

there is a continuing frequency with 1.7R but to move to 17.7R there is only one peak? Please explain this ring down again.

Is that the thing / combo that we are looking for?  I figured not.

Ringing is what I think we are looking for, isn't it?

please explain this , or give it a go anyway?

thanks

jeanna

http://www.coilgun.info/mark2/rlcsim.htm

[Pirate88179]

@ Jeanna:

I copied and pasted this from your coilgun site in case you didn't see it.  It speaks of ringing.  I ran the simulator a few times.  Very cool.  Thanks for sharing it with us.


"Role of Resistance

The graph's shape is very sensitive to resistance. At rather high resistance it is the main limiting factor on the current in the inductor, and you see the capacitor merely discharges slowly. At medium resistance you will see one lump of coil current which quickly dies out. At very low resistance it will ring (oscillate) as the energy sloshes from capacitor to inductor and back again.

One goal during construction is to minimize the resistance. Don't be too worried about ringing in a coilgun, because the projectile should absorb most of the coil's energy, leaving only a small amount for ringing. If you use an SCR to switch the coil then it will cut off after the first half cycle leaving the excess energy stored in the capacitor again, helping to prepare it for the next firing."


Bill

[jeanna]

@Bill,
good addition, thanks. Yes, it is a good place to spend an afternoon.

The thing we really cannot do much about is resistance. We can use fat wire and that is all. Using fat wire does nothing for resistance between the 2 different wires, or the wire to bolt resistance or the earth resistance for that matter.

I think this is where I started wanting to know if there could be a way to tweek the magnetism and not have to deal with the resistance, hence I asked myself what role the thickness of the iron wire played in our coils. Also, I used a hollow steel pipe.

BTW that hollow steel pipe produces the best readings. It is the one that gave a steady 18.9 mA inside. That reading went down with the addition of the secondary as they all do, but it is still the best.

Who knows if it is the hollow-ness or the larger diameter that is doing this?

I am not finished with the triplet of coils that looks at the thickness of the wires vs. magnetism  question. So, there is more to come. 

jeanna

[Pirate88179]

@ Jeanna:

I just now tried a trick I used on the electrode set-up in the very beginning. I stuck a very powerful neo magnet on the top of my core and took readings.  NO changes of any kind were observed in volts or amps.  In the electrode experiment, the volts went up a bit.

This, as you know, is over my head with the concept of ringing/oscillating.  Were you suggesting that, assuming this concept does apply to our coils, this wave form peaks at the beginning and would peak again IF it had the chance to get to zero? (or equally below the baseline as it was at the peak)  I have been thinking about that.  It almost sounds to me like we could use, 1. a capacitor, and 2. possibly a transistor to accomplish this?  What do you think?  I was thinking along the Bedini line of thought.

Bill

[jeanna]

neo magnet on the top of my core and took readings.  NO changes of any kind

well I think a steady magnet won't do anything to this cuz i dunno.

Over your head? I guess we are all getting taller fast around here! 

concept of ringing/oscillating. 

I need to understand this more. no, I wasn't talking about that because I don't know enough... yet.

this wave form peaks at the beginning and would peak again IF it had the chance to get to zero?

But on the pic with the higher resistance, it stops oscillating all together. You can see that it was oscillating by looking at the other pic. and gradually the osc changed until it hit that higher resistance and it stopped. At the same time, the amperage goes down which is the bummer.

1. a capacitor

I have played with caps but I don't really know how to make a circuit with the RLC. I keep going back to those sites so some day I will get it. I think the spark gap thing folks were talking about is the result of the cap, but i dunno.

2. possibly a transistor to accomplish this?  What do you think?  I was thinking along the Bedini line of thought

.
I love transistors. I think the earth is going to see a lot of charge in the coming years. Sunspots etc. They could blast a transistor, esp one in the open air so, I want to avoid them only for that reason.

jeanna