Tesla Trifilar Wound Coil for Spark production?

[Cycle]

Hi, all.

In another forum, I was reading about Tesla bifilar wound coils, and how they create a much stronger spark than a regular coil.

So I got to thinking, why not a *tri*filar wound coil? Wouldn't that provide an even stronger spark?

So, I mocked up a drawing (see attached). As you can see, it's a standard Tesla bifilar wound coil, with an additional winding on the outside of the standard bifilar coils. The additional winding would be of smaller wire, and would be approximately the same number of windings as both the other windings put together (so if winding 1 and winding 2 each had 100 loops, then winding 3 would have 200 loops).

Having very little in the way of electrical knowledge, I'm hoping some of you can answer my questions.

1) Would this provide a stronger spark over a regular coil?

2) Would this provide a stronger spark compared to a Tesla bifilar wound coil?

3) Would making a quasi-quadfilar wound coil be better, with the purple wire coiled inside *and* outside the two regular bifilar coils, then connected in parallel?

4) If I were going to build one for use on an engine, and built it to produce a spark strong enough, how would I isolate any back-EMF from the ECU?

5) Is there an algorithm in which one could plug in the wire size, wire length, number of loops, etc., and determine roughly how many ohms resistance the coil will have?

6) Is there an algorithm in which one could plug in those same parameters, along with the voltage that is pulsed into the first winding, to determine how much voltage one would get out of the third winding?

7) What would be best to use for the coil core? Air core? Regular iron core? Ferrous fluid core? Permanent magnet core?

8) How would one go about measuring high voltage? I want to aim for making about 75 to 100 kV. Is there such a beast that can measure that kind of voltage?

9) Is there coil winding equipment one can purchase or build, or does one do all this by hand?

Thanks, guys.

[Bob Smith]

Hi Cycle
Here's something I posted on another forum that might be of interest to you:

This guy's done a lot of work with coils on cars and to amplify voltage (not sure about amperage):
Making coils:
PositiveKML inline Step 1 - YouTube
Check out some of his other coil-related vids as well.

I would also suggest you check out posts by Allen Burgess on this forum. He's done some work with a quad-filar coil and has a lot of neat stuff to say about series-wound bifilar coils, also going by the name synchro1 on another forum.
All the best,
Bob

[Bob Smith]

Check out this thread too:
http://www.energeticforum.com/renewa...-products.html
B

[Ernst]

more is not always better

1) Would this provide a stronger spark over a regular coil?

2) Would this provide a stronger spark compared to a Tesla bifilar wound coil?

3) Would making a quasi-quadfilar wound coil be better, with the purple wire coiled inside *and* outside the two regular bifilar coils, then connected in parallel?

4) If I were going to build one for use on an engine, and built it to produce a spark strong enough, how would I isolate any back-EMF from the ECU?

5) Is there an algorithm in which one could plug in the wire size, wire length, number of loops, etc., and determine roughly how many ohms resistance the coil will have?

6) Is there an algorithm in which one could plug in those same parameters, along with the voltage that is pulsed into the first winding, to determine how much voltage one would get out of the third winding?

7) What would be best to use for the coil core? Air core? Regular iron core? Ferrous fluid core? Permanent magnet core?

8) How would one go about measuring high voltage? I want to aim for making about 75 to 100 kV. Is there such a beast that can measure that kind of voltage?

9) Is there coil winding equipment one can purchase or build, or does one do all this by hand?

Thanks, guys.

1) depends on how you plan to connect and use it, but I think its performance will be between a regular and a bifilar coil.

2) Do you understand what Tesla's purpose was in winding a coil in this manner? Have you read the patent (512.340)? If you do, this question will be answered (negative).

3) Depends on your usage and purpose, but from what I read here I'd say: "No".

4) Perhaps a HV UF diode could help you. Or using a primary?

5) Yes, there are tables that give you the resistance per meter for every AWG Cu wire. Multiply by wirelength. It's that easy.

6) There are more parameters that would determine the output; Coil self-resonant frequency, inductance and capacitance (incl. external capacitance), input frequency, waveform, voltage and current. It is a bit too complex to give you a full answer here. If you would tell us how you plan to connect this coil, that could narrow it down a bit.

7) Unless you intend to use a moving magnet, I think the options are: regular iron (low frequency), ferrite or the like (high frequency medium HV), air (HF HV).

8) They probably exist, but it will be way cheaper to make one by yourself. If you are not interested in output waveform you can just build a voltage divider. But calculate what voltage will appear across every resistor, and keep it low enough to avoid sparking. Also calculate what current will flow and what power is involved (both overall and per resistor).
If you also aim this value for your coil, then you should forget about multi-filar windings.
For example rubber or oil gives you 6-8 KV insulation per mm, meaning that you will need 1.5 - 2 cm insulation between the wires. (half that value in the bifilar coil windings, 3/4 that value in the windings of a coil of your design)

9) There probably is, but doing it by hand is MUCH cheaper. Especially if you only need 1 coil.

Ernst.

[wantomake]

Trifilar coil theory

Dear members,
Any advice or websites that have good animation teachings on the trifilar coils.

I've been spending much time experimenting with the Lockridge device. The trifilar coil has been a challenge and pain.

Thanks in advance,
wantomake

[keithlacon]

Tough trifilar coil has been a challenge and pain but it was nice to experiment it. And it was also very interesting to know about it.

peau d'orange

[Cycle]

1) depends on how you plan to connect and use it, but I think its performance will be between a regular and a bifilar coil.

2) Do you understand what Tesla's purpose was in winding a coil in this manner? Have you read the patent (512.340)? If you do, this question will be answered (negative).

3) Depends on your usage and purpose, but from what I read here I'd say: "No".

4) Perhaps a HV UF diode could help you. Or using a primary?

5) Yes, there are tables that give you the resistance per meter for every AWG Cu wire. Multiply by wirelength. It's that easy.

6) There are more parameters that would determine the output; Coil self-resonant frequency, inductance and capacitance (incl. external capacitance), input frequency, waveform, voltage and current. It is a bit too complex to give you a full answer here. If you would tell us how you plan to connect this coil, that could narrow it down a bit.

7) Unless you intend to use a moving magnet, I think the options are: regular iron (low frequency), ferrite or the like (high frequency medium HV), air (HF HV).

8) They probably exist, but it will be way cheaper to make one by yourself. If you are not interested in output waveform you can just build a voltage divider. But calculate what voltage will appear across every resistor, and keep it low enough to avoid sparking. Also calculate what current will flow and what power is involved (both overall and per resistor).
If you also aim this value for your coil, then you should forget about multi-filar windings.
For example rubber or oil gives you 6-8 KV insulation per mm, meaning that you will need 1.5 - 2 cm insulation between the wires. (half that value in the bifilar coil windings, 3/4 that value in the windings of a coil of your design)

9) There probably is, but doing it by hand is MUCH cheaper. Especially if you only need 1 coil.

Ernst.

Hi, Ernst. Thank you for your detailed reply.

1) I intend to use it as a higher-voltage replacement to the decidedly wimpy ignition coil on my scooter. I'm casting about trying to find a coil that can continue to provide sufficient spark energy even when the engine's turning at 10,000 RPM, but at the same time, not have so much magnetic reluctance (and inductive reactance) that it affects spark timing. I need it to release that voltage all in one burst when the magnetic field collapses. And do that many times for any one spark event.

2) Yes, I read the patent... he was attempting to decrease coil inductive reactance, thus minimizing the need for condensers (capacitors) at the coil's resonant frequency, while enhancing the energy stored in the coil. Back to the drawing board, then. Is there some means of using a one-wire type coil (ie: no primary and secondary, just one coil) to build up magnetic flux, then release that collapsing magnetic flux as high voltage (75 to 100 kV) by blocking the path back to the low-voltage source with diodes? I thought that's what the Tesla bifilar coil did.

3) Ok. See 2) above.

4) I'm trying to avoid using a primary. My goal is to build high voltage quickly, and release it quickly. At a much higher frequency than just the spark timing... the basic premise is to hit the spark plug (minus the J-curve ground electrode) with high frequency voltage pulses that end in such a short time that while it can create high voltage streamers, it never enters the arc phase. In this way, free radicals (electrons) are distributed throughout the combustion chamber, igniting the whole of the air:fuel mixture at once, rather than in one small spot and having a flame front sweep though the combustion chamber, as is done with conventional spark plugs. By doing this, the possibility for knock is removed, no matter how lean the air:fuel mixture is (ie: no flame front collisions, since it all ignites at once) and combustion proceeds and ends much more quickly (allowing one to retard spark timing to TDC or slightly ATDC, thereby enhancing engine efficiency since the piston doesn't have to push against the ignited and expanding fuel:air mixture that last ~20 degrees of rotation BTDC). Reference the research (and forthcoming products) from Siemens on high-frequency corona discharge ignition systems... of course, they'll never make one to fit a scooter, so I have to make my own.

5) Good to know. Thank you. My OEM ignition coil is 0.6 Ohms, so I want to be sure to stay at or above that, to prevent blowing out my ECU via over-current. Another question... is there any equation for determining how much reactive inductance a coil has, or does one just have to build and measure?

6) The coil would be connected from the ECU (probably via HV diodes, as you outlined) on the inlet side to the spark plug on the outlet side. Of course, the other side of the ECU and spark plug would go to vehicle ground to complete the circuit.

7) So air coil it is. That'll affect how much energy can be stored in the coil as a magnetic field, so I'll have to design accordingly.

8) Makes one wonder how the OEM ignition coil manufacturers do it in such a compact format and still make 15 kV... my OEM coil is only about 3 inches square.

9) Yeah, I see what you mean... ukcnc.info has coil winders, but they run from ~$1720.00 and up. Ouch.