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Re: Fluke 27 and Transformer Oil

Hi Nathan,

	Welcome to the Tesla list!!

My thoughts are below...

At 08:25 AM 12/23/1999 -0800, you wrote:
>Greetings!
>
>I am Nathan Ball, 16 year old coil builder and new to the list.
>
>I have a couple of questions:
>
>I have access to the use of a Fluke 27 DMM and was wondering if there was a 
>way I could use it to measure the output current on the 15/30 NSTs i 
>rebuilt.  It says in the manual that the max input voltage for AC mA is 
>600V...

There are plans for a "Tesla coil proof" current meter that can be built
for $35 at:

http://www.peakpeak-dot-com/~terryf/tesla/misc/meter.jpg

	You "can" use the fancy Fluke or other electronic meter as I and many
others have.  However!.!.  when I use them, I am willing to risk blowing
them up.  When you are measuring current, the voltage is very low so the
600 volt rating is enough.

	The problem is if ANYTHING goes wrong (the fuse blows, the table is damp,
a lead is loose, etc...), the meter will get fried like bacon.  There are
all kinds of little details and precautions you need to be sure of and even
then you are really taking a big risk of killing the meter.  Unless you
know exactly what you are doing and have money in your wallet to buy a new
meter, I would not us the Fluke.  Many people can successfully used a fancy
meter but there are a lot of dead meters in Tesla coiler's junk boxes too
from trying this.  I will guarantee that the meter will be TOTALLY
destroyed and not just "scratched" if something goes wrong.  When it works,
it is beautiful, but when it goes bad it is horrible!

	Personally I don't mind hooking up my old Radio Shack DVM to neons but I
wouldn't let my new HP34401 near a plugged in neon...

>
>Also, I am building some new capacitors that will add up to 0.0265 
>microfarad to match the new power supply of 15/150.

	You could actually double the capacitance value to get even more energy
but what you have will work fine.  Be sure to use safety gaps across the
neon.  That cap value is at the resonant point of the 150 mA neon.  If the
gap does not fire to drain the energy from the transformer/cap combination,
the voltage will skyrocket to about 80,000 volts and blow something (the
part you love most - a law of nature ;-0) up.

>
>I built a 0.0053 uF cap before and used 8 sheets of LDPE between each plate. 
>  I have since seen most people using at minimum 60 total mils and mostly 
>aroun 80-90, but I have never had any problems running a 15/30 through it.
>
>I think it may be because of the extremely pure transformer oil I got to put 
>it in... but do you guys think 0.048 inches is enough for a 15/150?

People usually recommend more but I am not the expert on this...

Cheers,

	Terry


>
>Thanks in advance!
>
>Nathan Ball
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