Re: Wild Idea OLTC - Split core inductors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "jimmy hynes by way of Terry Fritz <twftesla-at-qwest-dot-net>" <chunkyboy86-at-yahoo-dot-com>


another way to get the voltage gain would be to have a small inductor, maybe
100uh,  between the line and the capacitors with a diode preventing any reverse
current. when the igbt fires current builds up in the inductor and when the
igbts shut off the current is forced into the capacitors. because the igbts are
only conducting for about 100us the inductance must be small and the current
must be high for this to work, so you would probably need a capacitor to supply
the current. with a little more work  you could get away with higher
inductances and lower currents by letting the inductor resonate with the caps
until the next gap firing. if you turn on the igbts when there is still current
flowing in the inductor, then the inductor could pull even more energy out of
the wall. if you do that then the firing voltage would rise until you change
the firing timing. i was also going to suggest a voltage doubler but i guess im
too late :-). what ever you do get! rid of the big inductors, they kinda defeat
the purpose. 

 Tesla list wrote: 
>
> Original poster: "Terry Fritz" 
>
> Hi Richard,
>
> I tried this:
>
> http://hot-streamer-dot-com/temp/OLTC08-17-01.gif
>
> Both caps charge to 100 volts each but the diodes between them won't allow
> current to flow. The output terminals are the same as the output of the
> first bridge rectifier.
>
> I tried to fix this by putting the IGBTs between the caps and fire the
> IGBTs on the zero voltage crossing:
>
> http://hot-streamer-dot-com/temp/OLTC08-17-02.gif
>
> Problem here is that the primary coil is directly across the output of the
> bridge rectifier. It draws about 5000 amps off the AC line ;-)
>
> The whole thing seems promising, but I just don't see how to make it work. 
>
> Cheers,
>
> Terry
>
>
> At 12:59 PM 8/17/2002 -0400, you wrote:
> >8/17/02
> >
> >Terry,
> >
> >If you want higher peak voltage just use! a voltage doubler and eliminate
> >the inductors. It will only take a few additional diodes. Nothing is for
> >free though. There will be additional power required from the bridge. 
> >But, Hey! More power through put to the coil -- that's a good thing. I'll
> >try to draw a schematic, scan it and send a jpg file to you. There are
> >innumerable voltage multiplier schemes and I'm sure everyone has their
> >favorites.
> >
> >As for the timer pulse -- move the CT up to where it senses current just
> >past the bridge. Then you are more free to choose Cf capacitance. For
> >simplicity, I understand why you still tie switch firing to the mains AC
> >frequency. This does create overall severe coil performance problems as
> >does having the switch in series in the primary LC tank which destroys
> >synergy between the primary and secondary coil. Future generation low
> >voltage coils will, no doubt, require good DC voltage fil! tering if not DC
> >voltage regulation and complete control! of switch firing disassociated from
> >the mains frequency. Also, by necessity the switch will be outside the
> >primary LC tank. This will permit synergy and resonance will reign.
> >
> >



JImmy