The thing that kills NST's is over-voltage on the secondary side. They are
designed to power gas tubes, which clamp the secondary voltage, once
ionized, to several hundred volts (don't quote me on the number). They
were never designed to power capacitive loads which result in secondary
voltage in excess of the open circuit voltage. NST insulation in excess of
what's needed for powering tubes is not done and we're lucky to get away
with what we do.
NST's driving capacitive loads will pull a LOT of current. That in itself
is not hazardous to the NST unless you run it for so long that it heats up,
and then that's something that may degrade the insulation. But most hobby
TC's are used just very briefly so that's unlikely to be an issue.
Remember that mains current draw can be significantly reduced by adding
Power Factor Correction caps in paralled with the NST primaries. This will
have no bearing on TC performance, other than possibly boosting performance
by raising the available primary voltage to the NST's due to lower I*R
losses in the mains wiring.
Regards, Gary Lau
MA, USA
On Fri, Oct 9, 2020 at 10:36 PM shaun <snoggle@xxxxxxxxxxxxxx> wrote:
> That’s ok for some, but the secondary wire is so thin, I don't push the
> things, I would rather undervolt
>
> -----Original Message-----
> From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of yurtle_t via
> Tesla
> Sent: October 9, 2020 5:39 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Ballast
>
>
> Actually, many coilers remove some of the shunts to increase max current
> draw.Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: David Rieben <drieben@xxxxxxx>
> Date: 10/9/20 4:31 PM (GMT-05:00) To: Tesla Coil Mailing List <
> tesla@xxxxxxxxxx> Subject: Re: [TCML] Ballast Shaun, I would guess that
> the reason you don’t find much info on ballasting paralleled NSTs is that
> they are already internally ballasted by their core design, which limits
> the output current to a certain level regardless of the applied load. Most
> coilers only bother with external ballasting where it’s required, like for
> the inputs to PTs or pole pigsDavidSent from my iPhone> On Oct 6, 2020, at
> 2:21 PM, shaun <snoggle@xxxxxxxxxxxxxx> wrote:> > Just a quick question,
> has anyone added ballast in front of their paralleled> neon transformers
> for current limiting. I have searched for a few days and> not found
> anything. Thanks all> > _______________________________________________>
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