Re: variac

In a message dated 96-02-20 11:49:25 EST, tesla-at-grendel.objinc-dot-com writes:

>Subject: variac
>I remember reading a post from Richard Quick where he said that he wasn't
>satisfied with variacs as current limiters(as opposed to welders) I was
>wondering why?As long as the ratings are correct what is difference between
>the two?
>I plan on around 2kva for my current system using current limited


Richard is talking about ballasting required when using transfromers that are
not internally current limited - like neon sign transformers are,  and pole
pigs are not.  With pole pigs you want to use inductive ballast, like
achieved with an arc welder.  Using a variac for this purpose does not work
very well.  Variacs work well for slowly bringing the primary voltage up to
the desired operating level.  Welders offer heavy current ballasting and the
ability to change the inductance by adjusting the current settings on the

If you are using currrent limited transformers, all you need is a variac to
control the voltage.

Ed Sonderman