[TCML] No-load NST's

["Lau, Gary" <Gary.Lau@xxxxxx>]

Changing the subject line...

Yes - I too have heard many times that running an NST with no load will stress its insulation beyond what it was designed for.  But it does seem unlikely that an NST should be designed to self-destruct should its connection to the load fail.  So being the skeptic that I am, I have to wonder about the origin of that belief.  Did it come from a source in the sign or transformer industry, or just a coiler who observed that an in-use NST with a sign operates at well below its faceplate voltage?

Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of bunnykiller
> Sent: Wednesday, June 25, 2008 2:35 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Variac
>
> Hey Phillip...
>
> starting at 0 volts and bringing it up to operating voltage (120vac) is
> fine as long as the NST has a load attached to it. As far as going into
> the 125+ range with no load attached can be a bit hard on the
> insulation. NST's are designed to put out the nameplate voltage for
> brief periods of time when the neon tube is starting up ( not yet
> running) but once the tube strikes and lights up, the resistance is
> pretty low anyway ( something about negative resistance in a plasma).
> Kinda makes you wonder about all those NST's trying to fire off broken
> neon lites and how long they last in that situation...
>
> Scot D
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