Pure Inductive Ballasting vs Inductive/ Resistive Ballasting (fwd)

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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 personally haven't had much trouble with my am-
meter pegging out when operating my coil in this fashion and I am just 
not fond of those power devouring, power resistors in my control circuit.
Also, considering that pole pigs are designed for brutal 24/7 duty in the 
harsh outdoor environment (which includes occasional line hits from light-
ning strikes) for 20+ years, I don't think that I will have to worry about 
the 
pig giving up the ghost in typical, low duty cycle Tesla service. After all,
pole pigs and PTs are just a little bit more robust than your typical every-
day NST, MOT, or OBIT! Comments?

Sparking in Memphis,
David Rieben