Re: Hello again / New MOT coil (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 19 Jul 2007 16:31:05 -0700 (PDT)
From: G Hunter <dogbrain_39560@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Hello again / New MOT coil (fwd)

Thanks for all the info.  I'm both pleased and
impressed you made it work using the low-voltage,
high-current AC approach.  I avoided this route so I
wouldn't have to deal with the problems you seem to
have solved.

My level shifter had diode issues too at first, but I
was able to solve the problems quickly, and now my
diode strings have an indefinite life span.  I built a
second such coil and power supply for a friend, and
his exhibited the same reliability.  In other words, I
was able to make it work more than once.  I was so
confident about diode life, I sent him on his way with
no spares.  I don't think he'll need them.

Nothing against level shifters, but I'm always looking
for a cheaper, easier way to use MOTs.  A 100%
silicon-free TC intrigues me, especially with so many
coilers going the opposite direction.  A 4200vac
MOT-powered, spark gap coil seems like a throwback. 
That appeals to me.  If I ever get my workshop built,
I'll have to give it a try.

Cheers,

Greg

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> 
> ---------- Forwarded message ----------
> Date: Wed, 18 Jul 2007 18:19:22 -0400
> From: Jason Johnson <jasonmsusolar@xxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Hello again / New MOT coil (fwd)
> 
> Greg,
> 
> I tried using the level shifter type setup, but I
> blew two strings of diodes
> within the first 30 seconds of runtime. I decided at
> that point to go
> without the level shifter and power the coil with
> only 4200 volt input. This
> change from 12 kvdc to 4.2 kvac input meant that I
> had to rewire the MMC and
> the filter circuit. The MMC had already been
> soldered into a 3 x 10
> arrangement (for 45 nF at 20 kvdc), so this limited
> my easy option to a 6 x
> 5 setup (for 180 nF at 10 kvdc). If you look at the
> picture of the MMC, I'm
> sure you'll see why this was the easiest rewiring
> option. As far as the
> filter circuit rewiring, I just soldered a wire
> across 2 of my MOVs, giving
> me 8 series MOVs instead of the 10 I had previously.
> 
> Of course, going to such a low input voltage demands
> a big capacitor, and
> very tight tolerances in the spark gap. I found that
> if I closed the gaps as
> tight as my setup would allow, the spinning
> electrode would expand upon
> heating and jam up in the stationaries. With this in
> mind, I opened the gaps
> to about 0.060", and this seems to run very well. It
> takes about 75 volts
> input with no tank circuit to fire this, and about
> 65 volts input with the
> tank hooked up (obviously some voltage rise due to
> the caps resonating with
> the transformers and variac).
> 
> Jason
> 
> 
> On 7/18/07, Tesla list <tesla@xxxxxxxxxx> wrote:
> >
> >
> > ---------- Forwarded message ----------
> > Date: Tue, 17 Jul 2007 19:08:54 -0700 (PDT)
> > From: G Hunter <dogbrain_39560@xxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: Re: Hello again / New MOT coil (fwd)
> >
> > Are you firing this coil with 4200vac straight
> from
> > the MOT twins?  No voltage multiplier?
> >
> > Greg
> > (http://hot-streamer.com/greg)
> >
> > --- Tesla list <tesla@xxxxxxxxxx> wrote:
> >
> > >
> > > ---------- Forwarded message ----------
> > > Date: Tue, 17 Jul 2007 18:33:03 -0400
> > > From: Jason Johnson <jasonmsusolar@xxxxxxxxx>
> > > To: tesla@xxxxxxxxxx
> > > Subject: Hello again / New MOT coil
> > >
> > > Hi all,
> > >
> > > I have been away from the list for several years
> > > now, though I have recently
> > > returned to the hobby of Tesla coiling. Over the
> > > past year or so I have been
> > > putting a new coil together, which I recently
> > > completed. It is powered by
> > > two MOTs, with a big MMC and an asynchronous
> > > propeller style rotary gap. I
> > > put a simple webpage together to detail the coil
> > > with pictures and such, you
> > > can find it at:
> > >
> > >
> >
> >
>
http://mse-gsd1.matsceng.ohio-state.edu/~glenn/jason/Tesla%20site_files/page0001.htm
> > >
> > > This website is hosted by the professor I
> currently
> > > work with at Ohio State
> > > University, his page may be of interest as well
> - he
> > > does research into
> > > electromagnetic forming of sheet metal.
> Basically
> > > quarter shrinking, but
> > > slightly more productive. Just go up a directory
> to
> > > (
> > > http://mse-gsd1.matsceng.ohio-state.edu/~glenn)
> to
> > > check out some high
> > > velocity metal forming stuff.
> > >
> > > Let me know what Y'all think!
> > >
> > > Regards,
> > > Jason
> > >
> > >
> > >
> >
> >
> >
> >
> >
>
____________________________________________________________________________________Ready
> > for the edge of your seat?
> > Check out tonight's top picks on Yahoo! TV.
> > http://tv.yahoo.com/
> >
> >
> >
> >
> 
> 
> 



      ____________________________________________________________________________________
Fussy? Opinionated? Impossible to please? Perfect.  Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7