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Re: Blown Neon transformers

tesla-at-grendel.objinc-dot-com On Mon, 1 Apr 1996 08:30:50 +0700, you wrote:

>>From jwatson-at-students.uwf.edu Sat Mar 30 01:15 MST 1996
>>Received: from castaway.cc.uwf.edu (root-at-castaway.cc.uwf.edu [143.88.1.224]) by uucp-1.csn-dot-net (8.6.12/8.6.12) with ESMTP id AAA13427 for <tesla-at-objinc-dot-com>; Sat, 30 Mar 1996 00:02:05 -0700
>Date: Fri, 29 Mar 1996 13:00:46 -0600
>From: Jim Watson <jwatson-at-students.uwf.edu>
>Mime-Version: 1.0
>To: richard.quick-at-SLUG.ORG
>Cc: tesla-at-objinc-dot-com
>Subject: Blown Neon transformers
>Content-Transfer-Encoding: 7bit
>
>Hello,
>
>   I completed my large transformer today, and two of the four neon 
>transformers went bad after just a few minutes of operation.  I was 
>using four 15kV neon transformers in parallel, one 60mA and three 30ma. 

[snip]
>   When I was tuning this coil, the only sparks that I got were some 
>very intense thick blue arcs that went from one point on the toroid to 
>either the beginning of the primary (about 3') or the beginning of the 
>RF gorund. 
3' on your first try. impressive!

Put a strike rail above you primary and ground it.  This is a turn of
copper tubing above you last primary turn. Leave about a 1" gap
between the ends of the tubing so that you don't make a "shorted
turn". This gives any arc a ground to strike rather than the primary.
Your neon just wasn't up the megavolt hit that it took.

> The arcs were very fast, went straight down, and I could not 
>tell precisely where they were striking.  The point that the arcs 
>originated from was the blunt end of a brass screw that was pointing 
>down (it is now very smooth and is pointing up).
>
>   I would appreciate any comments or suggestions that you can find the 
>time to make.  I would like to think that the transformers were weak, 
>but I just don't really believe they were.  I don't want to replace them 
>and have the same thing happen again.
I've had problems with all 3 of my neons. They were all used when I
got them and 2 of them  have developed shorts at the HV bushing. 1 had
a cracked bushing, the other I've not taken apart to examine.

	jim fosse