Re: 15kV Neons and a pole oinker. (fwd)
---------- Forwarded message ----------
Date: Tue, 21 Apr 1998 10:14:13 -0600
From: Keith Maddox <kmaddox-at-burgoyne-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: 15kV Neons and a pole oinker.
CONNECT IN PARALLEL Yes you can hook up the neon (NSTs) in parallel to get
the 60ma. NSTs have two secondary windings which each have one leg hooked
to the core which is grounded, therefore you cannot connect them in
series, if you try, you;ll fry one or both.
You are right, they do need to be in phase. Since the two are identical
you can just set them up so that the primary bushings are facing the same
direction (both on the left for example) and connect the secondaries
accordingly. Trial and error wont hurt them either. You'll either get
nothing or everything.
CAUTION I'm sure you know this already but since it sounds as though you
are inexperienced at this, please be very careful as the output of even
one of these is lethal. I knew a guy that worked for a neon sign company
for many years and he had some awful grusome stories about nasty injuries
and even death caused by these.
CURRENT LIMITING Yes, they have current limiting. This is usually
accomplished by shunting plates. These plates are made a insulated
silicone steel laminates usually about 20 per unit and there are 4 units
placed so that some of the flux (magnetic energy) is shunted away from the
secondary coils. The more load, the more these shunts take away from the
secondaries. You can short the secondarys of an NST and run it forever
without harm. Actually, a neon sign connected to one of these
transformers, looks like a short. A neon sign operates exactly like one of
those little neon light bulbs you can buy at Radio Shack. You need to put
a resistor on those before you connect it to a low impedence source like
120 house current or you'll blow the bulb. This is why the NSTs are
current limited too.
JACOBS LADDER NSTs are an excellent choice for a jacobs ladder because of
their built in current limiting. Again, you can run one for extended
periods of time without any harm. The ladder itself however will get
quite hot, possibly cause a fire, or electricute someone :-) I mess with
them myself, I just think they are neet looking.
POLE PIG Just like the NSTs, pole pigs come in many sizes. A common one
used in tesla designes is the 5 KVA unit. The advantages of these are
that they are oil filled which makes them more rugged around all of the RF
and voltage spikes. With a NST, the transformer is "potted" in tar which
is a solid even after the NST has been running for a long time at full
load, the tar still remains solid. The disadvantage with this is two
fold. #1 tar is a hydrocarbon and as such, contains a lot of carbon.
Under stress (rf energy etc), it forms carbon tracks which perminently
short out the secondary windings. #2 it stays hard, which means that any
carbon track formed, will stay there forever. With an oil filled unit,
they tend to be "self healing". Dont' be discouraged from using an NST
for a tesla coil however since, if the curcuits are designed right, you
wont have any trouble.
A poll pig is normally used to step 12000V down to 240V for household use.
As with most transformers, you can use them to step the voltage up too.
This is exactly what coilers are doing when they use a poll pig. Try this
with your NST's! Connect them in parallel and hook your 120 up to only
one of them. Then connect an electric drill up to the primary of the
other. Please ground both NST's though!
With NSTs like the ones you own are rated at 0.45 KVA so in parallel you
are getting about .9KVA or 1/5 th the capacity of a 5KV poll pig.
With a pole pig, you need the current limiting because is does not have
any internal limiter. As with most other transformers, if you overload
it, it will happily oblige for as long as it can until it cooks itself.
Have fun, keep one hand in you pocket or holding on to the plug.
Tesla List wrote:
> From: J. Day [SMTP:jon-at-axionet-dot-com]
> Sent: Sunday, April 19, 1998 12:05 AM
> To: Tesla List
> Subject: 15kV Neons and a pole oinker.
> I just got my hands on a pair of 15kV/30 mA neons. If hook them up parallel, then I will get 60mA... I am almost sure of that. I remember reading a message that said that two transformers must be "in phase" before the current will double. If they have the same line level input, then won't this be automatic? (the two transformers are identical brand/condition/etc).
> Is it true that these transformers don't need current limiting, as it is built in? What about for Jacobıs ladder? I want to try out the Jacobıs ladder for fun, and don't want to ruin my xformers before they get a crack at Tesla!
> And one last thing, out of curiosity.... how many 15kV neons does it take to get the power of a pole pig? (and where in the world do you get these monsters? ... I hope you don't steal them off the pole in my block, as my power would go out!!! and that means no tesla! heheh)
> Thanks for your time!
> And this list is always a GREAT read!
> J Day