RE: First Light for 10" Coil.

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

Original poster: "Peter Reid" <peter-at-reidconsulting-dot-com.au> 

Ben

Thanks, Let me know if you decide to make a power supply similar to
mine, there's lots more things I can point out to save you lots of time
etc.

I've have had MOT's die before, but only because I had done something
wrong.

When I first fired up my 10" coil, the safety gaps just kept firing, for
no apparent reason (I found the problem later). But I made the mistake
of widening the MOT Safety gap too much, too about 1/2in either side of
the Ground Post. It ran fine until I got the phase adjustment wrong on
the phase shifter this caused one of the MOTS at the top of the Stack to
arc from primary to secondary though the core. I believe that MOT stacks
can handle massive amounts of current for short time intervals; however
large voltage spikes will nearly always kill one or more. Good thing is
if you do kill it, only the dead ones need to be replaced.

I now have the safety gaps set so they 'just' won't fire at around
13,000V or so. They occasionally fire when the coil is running but only
when I get power arcs to ground or the primary. I believe that my 6Mot
Stack could easily handle running at 40A -at- 240V (9600W) for extended
periods of time without any trouble what so ever. Mostly due to the
large thermal mass of all the oil and the cooling surface area of the
container. There has been no noticeable heating of any of the
transformers / oil after 5 minute runs.

Btw, those containers are 5L ones with clip on lids that seal real well,
I found they are the perfect size, and cheap!

I didn't worry about matching the MOT, I don't believe it is that
important, the most important thing to worry about when choosing mots it
to make sure they are roughly the same Wattage. Mine are all around
800-900W. (So theoretically if insulation wasn't a problem It could
handle 5400W with no cooling, I dare say that my setup could handle
extended runs of up too 12kW.

Regards

Peter Reid.

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, 27 December 2003 1:20 AM
To: tesla-at-pupman-dot-com
Subject: Re: First Light for 10" Coil.

Original poster: Ben Haylett <bhaylett-at-shaw.ca>

Thanks for the info, Peter.

After seeing your pictures and system description, I am very tempted to
try
to emulate your coil, or at the very least your power supply.

Did you use 6 identical MOTs in your power supply, or did you merely try
to
match characteristics as much as possible? When using this
configuration,
have you had any MOTs fail due to the higher than normal voltage? And
finally, when you are operating at around 240V, 40 amps, how long do you
figure that you can operate at one time without endangering your MOTs
due to
overheat?

-Hope you're getting the info you need for fine tuning your
already-impressive system!

Ben


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, December 24, 2003 6:56 PM
Subject: RE: First Light for 10" Coil.


  > Original poster: "Peter Reid" <peter-at-reidconsulting-dot-com.au>
  >
  > Hi Ben,
  >
  > Thanks. My MOTs have all there primaries in parallel, and all the
  > secondarys in series.
  >
  > There is basically two sets of 3 MOT's running antiphase, such that
the
  > middle two's cases are grounded. For the MOT's that are floating at
  > higher voltages I removed the high voltage (ground) wire from the
  > transformer core so the core could float and hopefully help improve
the
  > hv insulation a tad. I have all the transformers in three plastic
  > containers, It allows for them to be easily transported and connected
  > with just banana plugs for the hv, and screw terminals for the mains.
  >
  > You can probably see on my web page how I have grounded one of the
  > boxes, with the green wire linking the two black terminals, then
running
  > up to the safety gap etc.
  >
  > The output voltage of my Transformer bank is about 12,000V, with an
  > output current of about 1.6A (shorted).
  >
  > Regards
  >
  > Peter Reid
  >
  > -----Original Message-----
  > From: Tesla list [mailto:tesla-at-pupman-dot-com]
  > Sent: Thursday, 25 December 2003 3:01 AM
  > To: tesla-at-pupman-dot-com
  > Subject: Re: First Light for 10" Coil.
  >
  > Original poster: Ben Haylett <bhaylett-at-shaw.ca>
  >
  > Congratulations on an impressive looking coil, Peter.
  >
  > How do you (and presumably Ted as well) have your 6 MOTs configured?
In
  > other words, what sort of series/parallel arrangement are you using,
and
  > what would the output voltage be?
  >
  > Ben
  >
  > ----- Original Message -----
  > From: "Tesla list" <tesla-at-pupman-dot-com>
  > To: <tesla-at-pupman-dot-com>
  > Sent: Tuesday, December 23, 2003 10:46 PM
  > Subject: Re: First Light for 10" Coil.
  >
  >
  >   > Original poster: tesla <tesla-at-paradise-dot-net.nz>
  >   >
  >   > Greetings Peter
  >   >
  >   > A most interesting coil and quite similar to my own
  >   >
  >   > Very interested in the way you have done things
  >   >
  >   > The differences
  >   > Mine has 90nF of the 1600v 0.33uF caps (like Robin Copini)
  >   > SRSG is currently 300bps and all electrodes are near the 90deg
and
  > 270deg
  >   > points. This needs fixing, How did you decide on the location for
  > your
  >   > rotating electrodes to set timing
  >   >
  >   > I use PFC of over 100uF and up to 6 MOT's. The MOTs I have are in
oil
  > and
  >   > phased about ground. I use 900watt xfrmrs. I run fixed ballasting
of
  > 22mHy.
  >   > I was intrigued by your ballast and would be interested in the
short
  > form
  >   > specs on that.
  >   >
  >   > I have just purchased the bits to put a dedicated outlet at the
house
  > so
  >   > should be able to run the thing flat out.
  >   >
  >   > My operating freq, toroids and so forth are pretty similar, I can
  > maker
  > the
  >   > beast do 2 metre O/P but I know it will do better when I get SRSG
  > timing
  >   > better and a dedicated mains. It will run > than 40amps if I let
it
  > so
  > need
  >   > to keep it at that level or things start to go wrong, like fuses
  > start to
  >   > blow.
  >   >
  >   > Hope to hear more from your expts
  >   >
  >   > Rgds
  >   > Ted L in NZ
  >   > ----- Original Message -----
  >   > From: "Tesla list" <tesla-at-pupman-dot-com>
  >   > To: <tesla-at-pupman-dot-com>
  >   > Sent: Wednesday, December 24, 2003 8:54 AM
  >   > Subject: First Light for 10" Coil.
  >   >
  >   >
  >   >  > Original poster: "Peter Reid" <peter-at-reidconsulting-dot-com.au>
  >   >  >
  >   >  > Hello Everyone on the Tesla Coil Mailing List.
  >msnip.........