Re: primary/mmc stuff

["acmnovak" <acmnovak-at-email.msn-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

snips

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, July 31, 2000 10:39 PM
Subject: Re: primary/mmc stuff


> Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> Hi Michael,
>
> At 11:48 PM 7/31/00 -0700, you wrote:
>
> >
> > Hello everyone,
> >
> > As some of you already know, I'm organizing a bulk MMC buy next week. I
was
> > wondering what the consequences of not having bleeder resistors is? Does
it
> > cause the cap to fail? Greg Hunters MMC failed and he didn't have
bleeders...
> > This is the only failed MMC case I can think of other than ones caused
by
> > direct strikes from their TC.
>
>
> Bleeder resistors, at like a penny each, are just a darn good idea!  They
> prevent the caps from unbalanced charging and bleed the caps down when
power is
> removed which has save a number of rear ends :-))


So they have nothing to do with the well being of the capacitor itself?
Where can you get them a penny a peice?(i know, I'm cheap... join the club)

>
> >
> > Also, Is it true that you can rate an MMC by it's max DC voltage for
your
> > transformer? We're going to be getting 1600 v -at- .047uF polypropylene
caps,
> > and I was thinking of putting 10 or 12 in a string. What's the minimum I
can
> > get by with to save $$$?
>
>
> The maximum voltage from a transformer is typically the RMS voltage times
> 1.414...  So a 15kV transformer's peak voltage is 21.213kV.  It has been
shown
> that an MMC cap can easily be used at it's DC, rather than AC, voltage.
So you
> can use 21213/1600 = 13.25 caps, or 14, 1600 volt caps with a 15kV
transformer
> quite safely (My EMMC uses 10 :-)).
>

What voltage are you running it at?
For cost purposes, I'll have 10 strings of 12 caps, (BTW I'm running on two
12/60)
That's (.047/12)10= 39nF  +/-5% Max voltage - 1.6(12)=  19.2kV
Not bad, That's a pretty big cap for only $120 ; )


> >
> >
> > I've decided on a flat spiral made of copper tubing for my primary. I
would
> > have gone with a more "novel" design approach but i wanted to have a
shining
> > example of a modern TC.  I'm sick of messing with flashovers and
> > overcoupling...
>
>
> The good ol' flat primary is something that really can't go wrong...
>
> >
> > I got a lexan cutting board from my local Big-K (K-Mart) for $8 which I
will
> > use as primary supports. I'm planning on making one as seen here:
> >
> >
<http://www.fwpd-dot-net/dona/tesla/primary.htm>http://www.fwpd-dot-net/dona/tesla
> > /primary.htm
> > Only, i'm not going to paint mine and it will be on a plywood table.
> > How far does the strike rail have to be before the primary arcs to it?
I'm
> > thinking only an inch and a half... Does that sound acceptable?
>
>
> Yes.  The strike rail stands out well to the fields and should attract the
arcs
> well.  However, don't be afraid of making the coil higher so that strikes
to
> the rail are not an issue.

My planned secondary measures 4" x 24" (10cm x 60cm) wound with 22 guage
wire. I'm not all that worried about primary strikes, but if the coil starts
putting out around a megavolt, the safety gaps and rf filter will get quite
a workout...

>
> >
> > How, exactly, would one mount these supports other than screws? I was
> > thinking of cutting little blocks of HDPE and gluing them to the side of
the
> > supports and then using nylon bolts to hold them down... Just a thought.
>
>
> Tyewraps and lashing them with nylon cord have worded for me.  I use nylon
> screws on my latest coil:
> http://users.better-dot-org/tfritz/newcoil/

Geez, It looks nice, but it must have taken at least 8 hours to put the
thing togather...  Where would I get a big peice of plexi or whatever you
used under your coil? I'd like to actually make my base out of lexan... What
kind of solvent would be used in this scenario? where might one find it?

Anyhow, I really like your new coil Terry! The primary and secondary look
flawless... Now for the base. What do you plan for that? Would you please
put some specs along with those pics, it looks pretty promising. Good Luck,

                -Michael


>
> Cheers,
>
>         Terry
>
> >
> > Thanks,
> >
> >         -Michael
> >
>
>
>
>