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Re: Ed's Pig answer
Tesla List wrote:
>
> Subscriber: teslacoil-at-mindspring-dot-com Sun Feb 16 21:55:30 1997
> Date: Sun, 16 Feb 1997 22:44:41 -0500
> From: "Kevin M. Conkey" <teslacoil-at-mindspring-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Ed's Pig answer
>
> > Tesla List wrote:
>
> > I operate coils from 2 KW to 13 KW from
> > two paralleled Lincoln AC-225-S arc welders and 5 to 15 KVA pole
> > trensformers with no problem. The welders are very smooth( no bucking
> or
> > thumping) and the current can be adjusted in very small increments. If
> > you want to be able to have infinitely adjustable current control,
> look
> > for welders which have a variable shunt rather than a switch on the
> > front panel.
> > That 19.9 KV pole is a great Tesla power supply. Nice find!
> >
> > Happy and safe high power coiling,
> >
> > Ed Wingate
>
> Ed,
>
> Do the people that use resistive ballast have the bumping and thumping
> because their welder is not the infinetly variable type?
Kevin,
No, not to my knowledge, I use both variable shunt and switchable type
welders in my systems and have never had a need to include any resistive
ballast in the power supply circuit. The bucking and thumping ( for lack
of a better term), I am refering to is normally associated with Variacs
or Powerstats being used in the power control circuit for inductive
reactance to control current. These units tend to be unstable when used
for current control, especially if you are using less than half the
winding, and benefit a great deal when some type of resistive ballast is
used in series with them to damp the instability.
As I stated, I am currently using 2 AC-225-S Lincoln welders in parallel
for current control with my new power cabinet. These welders are rated
for 225 amps welding current at 50 amps/240 V. input and have a switch
for welding current control (no variable shunts). With the outputs
shorted for Tesla current control they will handle 70 amps for short
periods.
I also have 2 AC-225-C Lincoln welders that I use periodically. These
are also rated for 225 amps welding current at 50amps/240 V input but
are lighter duty than the AC-225-S, and do have variable shunts. The
duty cycle of these units is not as long and they do tend to heat up
easier with long high power runs. Both types work equally well for me in
Tesla power circuits with no series resistance necessary. Other brands
of welders should work well too, but I only have personal experience
with Lincoln.
Ed Wingate
> What are the ratings of the welders that you have? I would like to
> compare.
> I have a 250A Century and am picking up a 300 A Lincoln this coming
> Sunday. Both are the infinatly variable type.
>
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