Re: [TCML] Dummy load for optimum cap size Experimentation

[Gary Lau <glau1024@xxxxxxxxx>]

I don't have an IR thermometer but I do have a digital thermocouple meter,
so...

Two possible problems with measuring the light.  I'd have to build a
ventilated, shielded enclosure to keep out ambient light, and that seems
like more effort than finding a way to couple the thermocouple to the lamp.


Additionally, I fear the thermal time constant of just the filament would be
faster than the long-term fluctuations in the chaotic gap firing rate, and
would show moment-to-moment variations in brightness.  I'm hoping that the
thermal time constant of the quartz tube and thermocouple will average out
such variations and yield a more consistent reading.

I'll try the kapton tape and see how that holds up.

Regards, Gary Lau
MA, USA


On Thu, Jul 29, 2010 at 5:18 PM, Yurtle Turtle <yurtle_t@xxxxxxxxx> wrote:

> Wouldn't it have to run a while to get up to temperature? Why not measure
> light
> intensity?
>
>
>
> ----- Original Message ----
> From: Binny <binny@xxxxxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Thu, July 29, 2010 8:00:55 PM
> Subject: Re: [TCML] Dummy load for optimum cap size Experimentation
>
> HI,
>     Wonder why one wouldn't use one of those non contact IR Thermometers?
> They're relatively inexpensive and fairly accurate.
> ----- Original Message ----- From: "Gary Lau" <glau1024@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Thursday, July 29, 2010 7:14 AM
> Subject: [TCML] Dummy load for optimum cap size Experimentation
>
>
> > I'm gathering materials and plans to perform this experiment -
> determining
> > the cap size that will extract maximum power from an NST, at 120 and
> 140VAC
> > input.  The power indication will be via monitoring the surface
> temperature
> > of the halogen lamp dummy load that replaces the primary coil.  I plan to
> > test a 15/60 NST, and two 15/30 NST's, all unmodified.
> >
> > I'm having a hard time figuring out how to fasten a thermocouple to the
> > quartz lamp tube.  I want the connection to be robust, as there will be
> > considerable thrash as I change NST's and cap sizes, and I don't want
> > lamp/thermocouple coupling to vary.
> >
> > Obviously I'll clamp down the thermocouple wire to the base of the lamp
> > assembly (http://drop.io/garylau), but could use guidance on the
> business
> > end.  I thought about just wrapping many turns of 30 gauge copper wire
> > around the thermocouple wire and quartz tube, but worry that the quartz
> and
> > copper will have differing expansion rates and might damage the tube.  I
> > have high-temperature polyamide (kapton) tape that I can wrap the
> > thermocouple to the tube - not sure how that will fare with the heat.  If
> > nothing easy presents itself, I guess I'll fashion a spring clamp to
> apply
> > gentle pressure to the thermocouple tip and tube.
> >
> > Any thought on this problem or the experiment design would be welcome.
> >
> > Also, I can't seem to locate the table that relates NST size and gap type
> to
> > suggested cap size.  It had been on hot-streamer and mirror sites, but I
> > can't seem to locate it.
> >
> > Regards, Gary Lau
> > MA, USA
>
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla