Re: Potting Diode Strings - yes!

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

Original poster: "PotLuck by way of Terry Fritz <twftesla-at-qwest-dot-net>" <potluck-at-xmission-dot-com>

Hi List,

Has anyone ever used Corona Dope for this purpose?

Rick W.
Salt Lake City

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, March 19, 2002 12:46 PM
Subject: Re: Potting Diode Strings - yes!


> Original poster: "Kevin Ottalini by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ottalini-at-mindspring-dot-com>
>
> All:
>     It is very important to pot the diodes in something not because each
> diode only sees 1kv but because the far end diodes see 15kv or more.
>
> The corona and leakage to the air alone can eventually cause arcing
> and failure (I've done it, I've seen it, it happens .. the cascade arc was
> wonderful to behold).
>
> The AC end sees 0 to 7.5kv too on a 15kv nst and that means the first
> diode off the AC side really sees ~1kvdc to ~7.5kvac potentials ... any
> leakage there and that diode or the next is history
> (contamination = leakage from dust, finger oils, coke, cat hair, that
> meter lead, your finger, etc etc).
>
> Not to speak of how to keep the whole chain isolated from everything
> around it as well.  Putting the whole string in a pvc tube is a good idea
> (Brian Basura did this).  Building each leg separately is a very very
> good idea.
>
> Potting is a very good idea and wax isn't great but much better than
> nothing at all.  I've used jewelry wax, which is a dry hard smooth wax
> (available in several hardnesses ... it even smells good).
>
> I successfully did some small HV parts in normal as well as vacuum
> encapsulating with this wax too up to 24kv in one case and 90kv in
> another (but I have a vacuum oven!).
>
> I did not do an exhaustive study of how the wax compares to the
> normal HV epoxy that I typically use.  However ... the epoxy costs
> $15 / 200ml, and the wax is $4.50 / lb or less.
>
> If there is interest in this wax, let me know and I'll do some real
> leakage testing and post the results back to the list.
>
> Kevin
>
> ----- Original Message -----
> Sent: Tuesday, March 19, 2002 7:01 AM
> Subject: Re: Potting Diode Strings
>
> > Original poster: "Jeff Kamla <jeffk-at-sinclair-dot-net>
> >
> > Hi  All
> >
> >   so if you pot your strings with anything you are going to have fun
> getting
> > them apart if one diode blows and you have to replace it, as Gary said
you
> > are going to develope less than 1kv across each diode so whats the big
> > deal.....
> >
> >                                                           jeff......
> > ----- Original Message -----
> > Sent: Monday, March 18, 2002 6:17 AM
> > Subject: Potting Diode Strings
> >
> > > Original poster: "Matthew Smith" <matt-at-kbc-dot-net.au>
> > >
> > > Hi All
> > > Can anyone comment on using PARRAFIN WAX for potting diode strings? I
> > > don't know what it's electrical properties are like, but it is
certainly
> > > easy to pour when molten...
> > >
> > > Cheers
> > >
> > > Matthew Smith
>
>
>
>
>