Re: Terry's DRSSTC - Controller Experiment

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "colin heath" <colin.heath4@xxxxxxxxxxxx>

hi terry,
           i think i was going along the lines of no secondary in place as 
you mentioned. this was recalling my induction heater experiments where the 
prob was at Fres the current went sky high.
i had not considered the fact of the secondary sucking energy from the 
primary and the loading effect. i think i see what your saying now.(it take 
s awhile im new to all this)
cheers
colin

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Wednesday, April 20, 2005 7:59 PM
Subject: Re: Terry's DRSSTC - Controller Experiment


> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Colin,
>
> Say were are way de-tuned.  The primary has very low loss and the current 
> just keeps ringing up and up and up...  The situation is were the voltage 
> getting through to the top is only say 1/4.  but if the primary voltage 
> rings up to 4X, you still get the same top voltage due to the enormous 
> current that is allowed to build up on the primary.  If you have say 
> 10,000 amps on the primary, you don't need very good tuning ;-)))
>
> Just imagine what happens to the primary current if NO secondary is in 
> place.  The current just quickly rises until something blows up!!  Since 
> the DRSSTC is not power limited, if you put 1000 Watts in, the current 
> will rise until 1000W + the stored energy gets out, one way or another....
>
> Cheers,
>
>         Terry
>
> At 12:33 PM 4/20/2005, you wrote:
> > hi terry,
> >            im confused why the current would go high at either side of 
> > Fres as the sum of the reactancr drops to zero at resonance right? 
> > either that or you are talking about something different with Fo like 
> > oscillator frequency? just asking to clear up some of the many clouds in 
> > my mind.
> > cheers
> > colin
> >
> > ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> > To: <tesla@xxxxxxxxxx>
> > Sent: Wednesday, April 20, 2005 7:17 PM
> > Subject: Re: Terry's DRSSTC - Controller Experiment
> >
> >
> > > Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> > >
> > > Hi,
> > >
> > > Antonio is right, as the coil is de-tuned, the top voltage tends to stay 
> > > rather constant but the primary current tends to rise dramatically!!  I 
> > > think Steve reported he could run with a very highly detuned coil but I 
> > > suspect he was driving far higher current through is big IGBTs.
> > >
> > > I am tuning my DRSSTC by finding the point of least current draw.  On 
> > > both sides of Fo the current goes way up.  It seems at the best tuning 
> > > the current draw is the lowest.
> > >
> > > I am not concerned about which mode it is in since the drivers do not 
> > > care and I really don't care either ;-)
> > >
> > > I think I can run my old Magnifier with the DRSSTC driver too.  I may 
> > > have to make a new top holder since I think I "borrowed" that from the 
> > > magnifier.  With the DRSSTC now, the magnifier should be far easier to study.
> > >
> > > Cheers,
> > >
> > >         Terry
> .............