RE: Ballast Form and Function

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Robert Hanford" <pomnept@xxxxxxxxxxx>

Hi Gregory,
If you are using a neon sign transformer, you don't need a ballast. They
(NSTs,)  contain current limiting shunts already. Only things like microwave
oven xfrmrs and pole pigs need this.
Hope this helps,
Robert Hanford

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Thursday, March 09, 2006 8:25 PM
To: tesla@xxxxxxxxxx
Subject: Ballast Form and Function

Original poster: Gregory Morris <gbmorris@xxxxxxxxx>

Hey folks,

Sorry if this is trivial, I generally like to search the archives
before asking questions like this, but it seems somewhat specific.

First of all, what I think I know: ballast is for current limiting,
it is basically a length of wire wrapped up in a volume-efficient
bundle--essentially a big resistor--and sometimes is wrapped around
an iron core to get the added effect of the impedance of a  good inductor.

And what I'd like to know: what range of resistance is good for a TC?
Is the iron core necessary or just beneficial? Specifically I got a
little heating element from dismantling a broken 1500W kettle. It is
about 2" - 3" in diameter and a quick calculation tells me it has a
resistance of about 10ohms. Is this applicable to the new 9/30
powered coil I am building, or should I just scrap it with the rest
of the kettle? If so, do you have any advice or links for when I make
my own ballast?

Thanks,
Greg