Re: [TCML] predicting phase shift

[DC Cox <resonance@xxxxxxxxxxxx>]

I'm not sure exactly when Jimmy did his work, but Mitsubishi made the first
commercial IGBTs in 1985.  We use some in 1996.  It was a long time because
of the very high cost of the initial units.  Other engineers I know
definitely did use IGBT switching on large inductive loads long before it
was applied to a Tesla coil circuit.

Dr. Resonance





On Wed, Jun 24, 2009 at 7:58 PM, Quarkster <quarkster@xxxxxxx> wrote:

> DC -
>
> Gary Lau's question was in response to your post stating:
> "You will see the light when you try it.  Been there, done that, about 7
> years ago." Since the thread was about zero current switching in DRSSTCs,
> your statement appears to claim that you were working with zero current
> switching of power semiconductors in DRSSTC systems way back in 2002.
>
> Since Jimmy Hynes is universally credited with developing (designing,
> building, operating and documenting) the first DRSSTC in 2002 and early
> 2003, are you saying ("been there, done that") that your DRSSTC predated
> Jimmy's??
>
> (Jimmy's logbook documenting his first DRSSTC is preserved at:
> http://classictesla.com/hot-streamer/chunkyboy86/index.htm )
>
> I'm just trying to make sure that I accurately understand the history of
> DRSSTC Tesla coils. As time goes on, it can get more and more difficult to
> remember exactly what was done, and by whom.
>
> Also, Duane Byland's book "Modern Tesla Coil Theory" was published in 1990,
> which certainly isn't 30 years ago.
>
> Regards,
> Herr Zapp (who is definitely NOT Finn Hammer)
>
> ----- Original Message ----- From: "DC Cox" <resonance@xxxxxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Wednesday, June 24, 2009 2:30 PM
>
> Subject: Re: [TCML] predicting phase shift
>
>
> I didn't scoop anyone, nor claim to.  I started building TCs back in 1961
>> and worked with MOSFET coils, pioneered by Dwayne Byland (also never
>> mentioned or credited on this list), back in 1981.   Byland started
>> working
>> with them in 1978 but I'm sure Hammer never heard of him either because
>> there was not an internet back then, and Byland did publish, only one
>> book,
>> but it has actual MOSFET circuits in the book --- published over 30 years
>> ago!   IGBTs have been around since they first engineered in 1979, and
>> were
>> first introduced in 1985 by a Japanese company.
>> Since we are a commercial company we don't publish everything just as IBM
>> or
>> Intel doesn't.  Just call IBM or Intel and ask them for a schematic
>> diagram
>> of a motherboard and see what happens.
>>
>> AC circuits typically use iron core inductors and their inductance changes
>> very little, but RF transformers without iron cores are a different beast
>> entirely.  If you do a simple calculation,
>> dI/dt vs. inductance you will see inductance changes with the rate change
>> of
>> current in a RF transformer.  RF transformers do change inductance with
>> changing current, AC transformers do not.
>> This is basic EE not rocket science.
>>
>> As for Hammer's comments, he mentioned it was open to criticism.  Then,
>> when
>> I try to help him, by suggesting accurately that his overshoot problem is
>> caused by a gate transformer turns ratio he goes off on me.  Frankly, I
>> was
>> stunned to realize he doesn't know inductance of an air core inductor
>> changes with rate change of current.
>>
>> My purpose on coming on the list is to try to share my experience and help
>> people, not constantly argue with them.  It seems jealousy lurks
>> everywhere
>> and anytime someone makes a positive suggestion he is actively attacked,
>> and
>> usually by someone who doesn't know what they are talking about.
>>
>> Now I know why professional engineers from Intel, IBM, etc., generally do
>> not participate in email lists.
>>
>> Moderator ---- time to end this thread as it is going nowhere fast and
>> serves no valid purpose on this list.
>>
>> Dr. Resonance
>> here to help, but definitely not to spend countless hours typing in
>> defense
>> of my advice.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Wed, Jun 24, 2009 at 4:46 AM, Lau, Gary <Gary.Lau@xxxxxx> wrote:
>>
>> Inductance changes as the current through it changes?  I don't think I've
>>> ever heard that before.  As most inductors are used in AC circuits and
>>> the
>>> currents are constantly changing, that would be basically all inductor
>>> all
>>> the time.  Please clarify?
>>>
>>> Judging by the video footage that Finn provided of his predictor
>>> operating
>>> in a coil, I believe that he did try it.  Exactly what did you do 7 years
>>> ago that scooped all other DRSSTC pioneers?
>>>
>>> Gary Lau
>>> MA, USA
>>>
>>> > -----Original Message-----
>>> > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
>>> > Behalf Of DC Cox
>>> > Sent: Wednesday, June 24, 2009 12:23 AM
>>> > To: Tesla Coil Mailing List
>>> > Subject: Re: [TCML] predicting phase shift
>>> >
>>> > Any time the current is changing dynamically the inductance also >
>>> changes
>>> > --- it pure physics and basic E.E., not smoke and mirrors.
>>> >
>>> > Dan McCauley addressed some of these concerns in his book on Modern
>>> > DRSSTCs
>>> > which he wrote about 3 years ago.
>>> >
>>> > You will see the light when you try it.  Been there, done that, about 7
>>> > years ago.
>>> >
>>> > D.C. Cox
>>>
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>
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