Re: Pure Inductive Ballasting vs Inductive/ Resistive Ballasting (fwd)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson" <tesla123-at-pacbell-dot-net> 

Hi David,

Tesla list wrote:

> Original poster: Tesla List Moderator <mod1-at-poodle.pupman-dot-com>
>
> ---------- Forwarded message ----------
> Date: Wed, 6 Dec 2000 23:08:29 EST
> From: Tesla729-at-cs-dot-com
> To: tesla-at-pupman-dot-com
> Cc: Tesla729-at-cs-dot-com
> Subject: Pure Inductive Ballasting vs Inductive/ Resistive Ballasting
>
> Hi all,
>
> I've got a question. I've read some info on ballasting of non-current
> limited transformers and I've noticed that a lot of coilers strongly re-
> commend the use of both inductance and resistance to ballast the
> power transformer, citing that the resistance helps attenuate the
> "bucking" that is generated by a purely inductive ballast. Personally,
> I've never had much luck trying to use resistive ballasts and I haven't
> seen any problem from using only an arc welder to ballast my 10 kVA
> pig. And resistance waste power in the form of excess heat which re-
> quires special fire-proof mounting hardware, fan(s), and adequate clear-
> ances to avoid any fire hazard. So, my question is do I need to rework my
> control panel to incorporate some form of resistance into my ballasting
> network to protect my pig against this "bucking," or can I keep right on
> happily sparking along with my 240/28 amp variac and Lincoln 225 amp
> electric arc welder?

I think running without the added resistive limiting is fine. I do use 2.5 ohms
in my control mod, but only because I was getting some heavy thumping at the
variac (I think I was using a variable speed RSG at the time). I'll
probably try
it without the resistor with the sync gap (if I ever get the real-time phase
adjustment finished - hopefully in the next couple of weeks).

One other thing - a pole pig can be killed - just ask Charles Brush (killed a
pig back in 1997).

Take care,
Bart