Re: Coil problem

To: tesla-at-pupman-dot-com
Subject: Re: Coil problem
From: Bert Pool <nikki-at-fastlane-dot-net>
Date: Mon, 6 Jan 1997 06:58:50 -0600 (CST)
Subscriber: nikki-at-fastlane-dot-net Mon Jan 6 21:59:08 1997
At 09:25 PM 1/4/97 -0700, you wrote:
>Subscriber: FutureT-at-aol-dot-com Sat Jan  4 21:22:55 1997
>Date: Sat, 4 Jan 1997 01:48:41 -0500
>From: FutureT-at-aol-dot-com
>To: tesla-at-pupman-dot-com
>Subject: Re: Coil problem
>
>In a message dated 97-01-04 00:51:39 EST, you write:
>
><< 
> >  -- Bert --
> >   >>
> > I've been using motor starter capacitors for PFC on my neons,  why are
>these
> > caps undesirable; danger of shorting out and/or blowing up?
> > 
> > Happy coiling,
> > 
> >    John Freau
> 
> "John,
> 
>"> Motor starting caps tend to be rather inexpensively made, planned for
> only intermittent usage, have higher Equivalent Series Resistance, and
> generally tend not to be nearly as "robust" as film caps made for
> continuous duty (and generally higher voltage). If you run motor
> starting caps for relatively brief times during coiling, they may work
> OK. But if you can get better ones cheaply, its probably wise to do so. 
> 
> BTW, have you noticed any heating or cap failures when using these as
> PFC's? Since I've not to used them (for the above reasons), I don't have
>> any run-time experience with them.
> 
> >-- Bert -- "
>  Bert,
>
>No failures yet,  I use the ones with the black bakelite plastic tubular
>cases that have a metal toothed ring pressed into the end to hold in the evil
>guts of it.    I can't remember for sure if they got warm or not--it's
>possible they got a little warm.  I know if they got quite warm, I would have
>remembered it.  BTW, I used them on a 12 kV, 30 ma unit.  I tried both 26 uF
>and 56 uF values (not at the same time), didn't make much difference in
>current input or spark output.  But either value of course reduced the
>current compared with no PFC at all.
>
>

John,

Then tubular black electrolytics are motor "start"" capacitors.  The way
they are used in real life is they are connected to a motor or refrigeration
compressor motor through a starter relay for about two seconds.  The relay
then opens and disconnects them.  They absolutely are not made for extended
connection to AC!  If left connected for too long they fail - and the stench
is awful.  Use the caps in the rectangular metal cans - these are known as
"run" capacitors, and are designed for continuous connection to AC.

Bert Pool
nikki-at-fastlane-dot-net