[TCML] quench times again
list at future-technologies.co.uk
Sun Nov 25 13:44:20 MST 2007
I just posted to another thread about SISG, no doubt you will read that
I forgot to post the URL
http://www.future-technologies.co.uk/IMPULSE/coil/coil.htm Half of it maybe
total nonsense as this was some time ago now. Though you can see how things
the SISG fired on the zero crossing of the AC wave to increase efficiency,
though I did not like SISG series fire operation, so I went for a parallel
operation.. latter I started to add in resonant mains side charging.... and
things just kept on going... the pages after that to be honest is "WIP" and
"ideas" it should not be published really, though ideas are always good I
I did plan to build my SISG design though I stopped work on it after a
while, I moved onto much lower voltages using a single IGBT. much higher
current and less voltages... and yes my High Q system does solve a lot of
problems, but as you say opens up a whole new set of problems!
All the talk on the list at the moment is my second idea to build a 20KV
high Q system.... factors such as resistance are not much an issue above
1KV... though 10VDC at 1,000amps, even a few fractions of a ohm can
seriously reduce efficiency..
Also a small toroid should be used, or none at all. it increases the
capacitance and lowers the Q of the coil. With such a high frequency anyway,
a larger toroid is bad yet again.. Though at this point other than trying it
one could speculate for years to come, and already spent the past year in
I think some of the confusion with everyone is I have 2 systems in mind,
what may work with a classic coil may not work with a high Q system... the
spark gap seems the limiting factors in just about every aspect, so if you
remove that problem and use solid state then you are onto a good thing and
have much more freedom to experiment with "new" designs... however solid
state is low voltage which opens up its own problems.. "win some, loose
IMHO, Tesla coil's need a new direction to go in, as solid state seems to be
the direction then building a "new" type of solid state coil should be
interesting... If design can be made easier, using off the shelf parts, with
much smaller toroids, lower voltages, 100turn secondary coils.. then the
advantages speak for itself.
No doubt if my design works, I will run into new problems in running.. my
secondary maybe under so much stress it could turn into a bright flash off
light and vanish into another dimension for all I know! Simulations can only
tell you so much!
----- Original Message -----
From: "Barton B. Anderson" <bartb at classictesla.com>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Sunday, November 25, 2007 8:03 PM
Subject: Re: [TCML] quench times again
> Hi Chris,
> I agree that this can be done to a point and about the trade-off of losses
> in this system. The fact is no one has done this that I'm aware of and it
> "is" new territory. At first, I wasn't sure. Too often a coiler thinks he
> is doing something new only to find out it wasn't new. In this case, I
> think it is new. The only one I know that has done something along these
> lines is Dave Sharpe with is IDR coil, but that really is in the primary
> area. Your secondary is completely different and sets up a whole new set
> of issues as well as eliminating quite a few.
> You have the ability to use a high frequency and keep the Q very high. It
> will be interesting to see if you can apply this method to a high voltage
> coil (plan B). I think you've thought this through very well and it's been
> an eye opener for me. We don't really know what type of problems will be
> The ring up and how the energy is stored in the secondary and top terminal
> will be interesting. Now I understand why you were looking at dwell
> reduction. Unfortunately, that just doesn't help and I'm not all that
> confident that a rotary is the best avenue for the coil. Have you
> considered maybe an SISG approach?
> Take care,
> Chris Swinson wrote:
>> Hi Bart,
>> I think some confusion is that when I mean higher frequency, I do not
>> mean smaller coils.. my Q factors always go up with the larger wire with
>> larger secondary coils.. Though you can only do this to a point as if you
>> make the coil length longer to keep the same turns but thicker wire, then
>> the HD ratio is a poor figure and chances are it will not couple
>> correctly to the primary..
>> So you are right in what you state, but it is not exactly what I am
>> Higher frequency does increase losses in some parts, but in other parts
>> losses can go down by a factor of 4... It is one huge epic counting up
>> all these "new" pro's and con's, though overall the higher Q system comes
>> out best..
>> The other problem is higher Q( generally) is higher frequency, which
>> needs a lower tank cap value, which reduces energy. So you cannot use
>> large tank cap values.. I got around about 250khz before running into
>> such problems.. So you have to rebuild and use a higher voltage to keep
>> the same power input with a small tank cap. Joules input is a lot better
>> at higher voltages and puts less current across the spark gap.
>> IMHO, once you get to 100nF tank cap, the voltage should go up for a
>> greater input power, not the tank cap value... In general 100-200nF is
>> about the limits at say 10KV, but I think 100nF should be the largest
>> tank cap which should be used. Rather than pumping more current, it
>> should pump more voltage instead... once you start to pump more voltage
>> input, you can use a lower value tank cap, so less current, and it opens
>> up the doors to much higher Q coils.
>> ----- Original Message ----- From: "Barton B. Anderson"
>> <bartb at classictesla.com>
>> To: "Tesla Coil Mailing List" <tesla at pupman.com>
>> Sent: Sunday, November 25, 2007 3:53 AM
>> Subject: Re: [TCML] quench times again
>>> Hi Chris,
>>> Only a little confusing, but not too bad. Anytime I start talking
>>> decrease this, increase that, I personally have periodic cross-thought
>>> errors (type just the opposite than I meant due to wondering off on a
>>> different aspect).
>>> There are of course losses associated with higher frequency. Usually,
>>> when coilers are talking a high frequency coil, it's geometric size is
>>> small and Q is not high. Here again now I've got to state, and yes log
>>> me down for this statement: "higher frequency does not result in a
>>> higher Q coil".
>>> Increase frequency by taking any coil and reduce it in 1/2. Thus, divide
>>> the radius by 2, the height by 2, the wire size by 2, and keep the same
>>> number of turns. Your frequency will double and Q will lower because the
>>> AC losses begin to increase. If it were not for those losses, I would
>>> expect the Q to remain the same.
>>> In your case, there is a high Q due to the higher conductance. Eddy and
>>> skin effects will not be hindered in your coil as it would in one of the
>>> smaller high frequency coils. This should definitely not be related to
>>> Q, but rather to the large wire size and it's low DC resistance and
>>> unaffected AC resistances.
>>> It should be true that as we reduce the number of transfers, the gap
>>> losses should decrease. I'm not sure that higher frequency would help
>>> ionization at the gap except that it will help to decrease the transfer
>>> rate (so more energy over a shorter period).
>>>> The idea really is that a higher frequency should allow a higher
>>>> current pulse with upsetting the RSG too much. It was also my point
>>>> about "making sure" by decreasing the RSG dwell time. As higher current
>>>> will be harder to quench, then decrease the dwell time and it should
>>>> help matters also.
>>>> A lot of factors come into play, as pointed out by yourself, John, etc.
>>>> Though this was really the overview of the "high Q" system which I had
>>>> in mind. A lot of ideas and corrections brought up in all these posts
>>>> thats for sure!
>>>> Everyone has been down the classic road, wider coils, more inductance,
>>>> larger toroids... So I am thinking of a "new" direction instead....
>>> But when you see certain aspects like Q increasing, look at what is
>>> different. In your case, it's really the few turns of large wire over a
>>> large area. This is a huge difference. Just take your coil and reduce
>>> the wire size by half and you'll see Q start to drop without much affect
>>> on frequency.
>>>> Another point which has not come into it yet, even though I mentioned
>>>> it. Higher frequency should also increase efficiency in it its own
>>>> for example, running from a 12V test setup, at 15cm "range" ....
>>>> 50hz =0
>>>> 39khz =0.5mV
>>>> 1mhz =50mV
>>>> 1.2mhz =70mV
>>>> 1.43mhz =120mV
>>>> 1.87mhz =150mV
>>>> 2mhz =200mV
>>> But is that a result of the frequency or is that a result of the coil
>>> geometry? Higher frequency is resulting in a shorter transfer rate and
>>> as a result di/dt increases at the secondary which increases the
>>> amplitude since the AC and DC losses are so low. But the same cannot be
>>> said for a high frequency coil which is small. The losses are huge then.
>>> For your particular geometry, I think what you said is true, but not
>>> across the range of coils.
>>>> I was wondering if this would also apply to coupling efficiency. In a
>>>> way it looks like voltage is lost over the coupling. Tighter coupling
>>>> would in effect reduce my "range" figure and double up on the voltage.
>>> I don't normally look at coupling as an efficiency number. Coupling will
>>> always be 100% regardless. There are of course losses over time at the
>>> gap and over the transfer. But yes, tighter coupling will increase
>>>> After a lot of testing I drew up that double the frequency gave x4 the
>>>> voltage output. As a relation, 10 times the frequency gave double the
>>> For your particular geometry.
>>>> Going by these figures, if a normal tesla coil used 1,000 turns at
>>>> 100khz, then it suggests a magnetic field which runs "out of steam" at
>>>> 1,000 turns. So increasing turns does nothing at all other than to gain
>>>> a few volts and increase resistance.... the point now that if we
>>>> progressed to 1mhz then we should be able to use 2,000 turns and the
>>>> magnetic field will run "out of steam" at the 2,000 turns mark.
>>> In a normal coil, the losses in eddy and skin effects will come into
>>> play and will be significant. But, if we go down the road of increasing
>>> the wire size and coil size in order to achieve 10x the frequency and
>>> double up on the turns, then yes, we can get reduce those losses.
>>> However, in reality the coil would be physically to big to build.
>>>> Also as frequency goes up you get more voltage. take 124khz 0.5mV to
>>>> 1mhz 50mV . This is all at 15cm "Range". When I say range, I mean the
>>>> distance between the primary and secondary. Remember only the
>>>> frequency changed and the voltage was constant at 12V.
>>> You can only get more voltage if the di/dt is increased without
>>> significant losses. For your particular coil which is really extreme I
>>> can see that happening.
>>>> It is one of those odd things which also confuses me about tank energy
>>>> going from primary to secondary. My own tests show there is a voltage
>>>> drop... if we take 124khz I input 12V and got 0.5mV output.
>>> Sure, there's always a voltage drop for any given point in time. No
>>> doubt about that.
>>>> Another problem is that Q factor was not taken into account with the
>>>> secondary. I used a variable capacitor to tune the secondary to the
>>>> primary. So Q factor probably was going up.. Though in anycase
>>>> frequency increase gave way to higher Q factor coils and gave greater
>>> The cap in the secondary is a terrific approach on your coil. I agree,
>>> but due to the few turns, large wire size, and coil size to accommodate
>>> the wire size I believe is why. Your coil is so far outside the loss box
>>> that the main loss in your system will be the gap. In a high voltage
>>> situation, it would be interesting to see how the voltage stresses
>>> Take care,
>>>> Even though I still have more tests to do. I got 16mhz as being the
>>>> best solution. I made me first think that the secondary coil over the
>>>> loose coupling would only obtain a fraction of the voltage. In which
>>>> case energy would be lost over the distance between the primary and
>>>> secondary coils.... always interesting none the less!
>>>> ----- Original Message ----- From: "Barton B. Anderson"
>>>> <bartb at classictesla.com>
>>>> To: "Tesla Coil Mailing List" <tesla at pupman.com>
>>>> Sent: Saturday, November 24, 2007 8:01 PM
>>>> Subject: Re: [TCML] quench times again
>>>>> Hi Chris,
>>>>> Another correction I need to make.
>>>>> As the number of cycles increases, the transfer rate will "decrease".
>>>>> What you are doing is interesting and how you are going about looking
>>>>> at how the frequency affects the transfer rate, efficiency, and gap
>>>>> conduction. Very interesting subject to me.
>>>>> Take care,
>>>>>> As the number of cycles increases, the transfer rate will increase.
>>>>>> Here is the relationship.
>>>>>> Total Energy Transfer = (0.5/((1/(1-k)^.5)-(1/(1+k)^.5)))*(1/fr)
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