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Re: Ballast for pole pigs or potential transformers.
From: Bert Pool[SMTP:bertpool-at-flash-dot-net]
Sent: Tuesday, November 18, 1997 6:07 AM
To: Tesla List
Subject: Re: Ballast for pole pigs or potential transformers.
>
>From: esmit-at-ilink.nis.za[SMTP:esmit-at-ilink.nis.za]
>Sent: Monday, November 17, 1997 3:25 AM
>To: tesla-at-pupman-dot-com
>Subject: Ballast for pole pigs or potential transformers.
>
>don't speak to technically, i am new to this stuff, PLEASE?
>
>Hi,
>
>I have read that when you buy a pole pig or potential transformer and want
>to run it on a Tesla coil you should use inductive ballasting or resistance
>ballasting.
>
>Will you answer some questions for me?
> * How do you know if a transformer isn't current limited?
If the transformer is not a microwave oven transformer, or a neon/OBIT
transformer, then it will not be current limited. All power distribution
transformers require ballasting.
> * What does an inductive ballast and resistive ballast do?
The ballast is placed in series with the primary of the transformer.
Because the current reaching the transformer must flow through the ballast
first, the total current available to the transformer is limited by the
current used by the ballast device. For example, if you use a 1500 watt
electric heater as a ballast, then the maximum power which will flow through
the transformer is limited to 1500 watts.
> * What is an inductive ballast(i know it is an arc welder, but is that the
>machine that you use to meld iron to each other?)
> * I probably wont use my fathers arc welder(if it's what i think it is)
>because it might be actually blow up or something, what else can i do?
An inductive ballast is simply a low inductance, high power coil, usually
wound on an iron core. Electric welders make excellent ballast devices, as
they allow a fair bit of control over the total current. And yes, we are
talking about your father's welder.
Max Hempel on this list is successfully using microwave transformers as a
ballast. He shorts out the secondary of the microwave transformer, then
places the primary of the microwave transformer in series with the primary
of the potential/distribution transformer - exactly as you would use a
welder. The microwave transformers cannot pass as much current as a welder,
and they do get very hot, but it works. Max is getting 5+ foot sparks out
of his coil.
You may also wind your own ballast on a very large laminated transformer
core, using large gauge wire. I have a 100 pound core that I plan on
winding with 6 gauge wire.
> * What is the difference between a pole pig and a potential transformer?
Potential transformers are usually limited to sizes of 5 kva or less. Pole
pigs are usually 5, 10, or 25 kva, or even larger. Pole pigs are filled
with oil - potential transformers usually are not.
>
>Thanks
>Richard
BTW, Richard, pole pigs are not for the inexperienced coiler. A potential
transformer or pole pig is not likely to just shock you - it will kill you.
These are the things that burn the legs and arms off linemen who
accidentally get across one of them. If you get one, use extreme care - I'd
suggest asking for first hand advice from an experienced coiler when that
time comes!