Re: Helping someone with broken coil (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

It's radius vs. diameter.  :-)

---------- Forwarded message ----------
Date: Tue, 21 Aug 2007 22:14:46 -0500
From: Drake Schutt <drake89@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Helping someone with broken coil (fwd)

Chip how is the primary (4.5") smaller in diameter than the secondary (7")?

drake schutt

On 8/21/07, Tesla list <tesla@xxxxxxxxxx> wrote:
>
>
> ---------- Forwarded message ----------
> Date: Tue, 21 Aug 2007 20:09:45 -0600 (MDT)
> From: Chip Atkinson <chip@xxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: Helping someone with broken coil
>
> Greetings,
>
> I was contacted recently by a guy who has a display coil  The capacitor
> blew up and he would like to get the thing running again.  Unfortunately
> he was unable to get any specs from the cap so I'm kind of winging it.
>
> His secondary looks to be 7" in diameter and 22" long.  The coil is
> powered by a 15kV/120ma transformer (nst?) and the primary has 10 turns
> with 4.5" inner radius and 13.5" outer radius.
>
> My question is what is a good capacitor value replacement?  I figure one
> rated for 45kV, but what capacity?  What have others used on coils of
> approximately this size?  My guess is 0.020-0.025uF.  Worth noting is that
> 0.021 uF is a resonant capacitor so it should probably be avoided.
>
> Thanks in advance.
>
> Chip
>
>
>
>