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Re: Ok.. where am I going wrong

Hi Michael,
After my post last night, I wondered about your hookup. I wonder, is it
possible
for you to provide info on your input setup? Maybe a quick diagram of hookup
components. Also, if you have voltage readings across each component before
the
transformer (resistor, ballast, etc.).  The total current (in series) x the R
value for each component is your voltage drop. I just don't believe you have
this much current passing (maybe you do for some strange reason, but it
doesn't
sound right to me). To calculate the total current, you must account for
inductive reactance (XL) of your ballast and your resistive values (R).
Then you
can find the total impedance of your circuit. V/Z= total current. Z = SQRT
(R^2
+ XL^2). Maybe you can calculate what voltage drop you should be producing
across the resistor.  R x total current.

What I goofed in my first post was the value of current if the 0.4ohm resistor
was the only thing in the circuit. I said 40+A. This was not right, it
would be
near 600A! Of course your limiting current with the ballast, but still, 17V
drop
is huge. It should be proportional to the total current passing through.
This is
why I question the hookup or the measured reading.

Sorry if this was redundant. Thought I should explain why I didn't like my
first
post.
Bart

Tesla List wrote:

> Original Poster: "Coiler" <mycroft-at-access1-dot-net>
>
> Ok.. since this is the third person to make this comment...
> The resitor is not there for the majority of the current limiting.
> It is only meant to smooth the surges from the purely inductive
> system. Each element in the system, as they are all in series,
> *must* see the total current passing through. This is the whole
> reason limiting works anyway. I had just hoped to take advantage
> of the fact that this smoothing resistor would have voltage drop
> across it proportinal to the current passing through it. I am just
> trying to find out why my wires are not getting warm, and the fuses
> are not blowing, yet my meter says I am exceeding my circut capacity
> by 50%. I have gotten some pointers to the problem, that I have not
> had a chance to test yet.
>
> Michael Baumann
> Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net
>
> > -----Original Message-----
> > From: Tesla List [mailto:tesla-at-pupman-dot-com]
> > Sent: Saturday, November 14, 1998 5:18 PM
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Ok.. where am I going wrong
> >
> >
> > Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>
> >
> > Michael,
> > For current flow, you must have both sides of the AC joined together. The
> > current flows back and forth from one leg to the other through the
> > components in
> > your circuit. The components are all in series forming a circuit
> > "loop". The
> > 0.4ohm resistor is just one component in the loop. In order to "calculate"
> > current flow in the total loop, you must account for all
> > resistance including
> > the resistance and reactance of the ballast, pig, etc... If your 0.4 ohm
> > resistor was the only thing in the circuit, then you would draw 40+ amps
> > across
> > the resistor and blow your fuses. Obviously, the current is being limited
> > by the
> > other components in the circuit.
> >
> > Hope this helps,
> > Bart
> >
> > Tesla List wrote:
> >
> > > Original Poster: "Coiler" <mycroft-at-access1-dot-net>
> > >
> > > I just finished wiring up my pig-training facility. This means the
> > > welder, 0.4 ohm resistor and 240V feed. I had thought to calibrate the
> > > switch settings on the welder to KVA numbers by taking voltage readings
> > > across the resistor. The infamous V=IR business. Only.. it didn't work.
> > > Or I don't think it did. At one point, I measured a drop of
> > 17V. This works
> > > out to roughly 42 amps. This cannot be. I have 30A fast blow
> > fuses in the
> > > line
> > > and I suspect that they would fry in short order at almost 50% overload.
> > > Therefor, there must be someting I am missing. I assume it is
> > related to the
> > > fact that this is AC.
> > > Could someone help me out here? Tell me where I goofed.
> > >
> > > Michael Baumann
> > > Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net
> >
> >
> >