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Re: Variac setting (Was Rd: Rotaty popping)
In a message dated 4/27/00 4:19:56 AM Pacific Daylight Time, tesla-at-pupman-dot-com
writes:
<< Hi Ed,
In this reply you made to John, I noticed your variac setting and reaction to
change is **identical** to my variac setting and reaction. I too have little
change in performance with movement of the wiper to about 25% or so. I also
find my best performance just about center of the variac. This makes me
wonder
why we are seeing such a similar reaction. I believe we are both using a
variac
and series resistor combo (my smoothing resistor is 2.5 ohms). I wonder if
others using this setup with a pig or potential xfmr are seeing the same type
of reaction? I find this fascinating - because I don't understand why. Your
ballast is a 40A and my ballast is 30A. BTW, I measured my variac (setting at
mid winding) at 11.2mH. I would assume yours is a bit more (maybe 16mH or
so).
Does anyone else see this similarity? Does anyone have a theory why?
Bart >>
Bart,
I measured my ballast variac last night. It is made by Luxtrol, says Light
Control on it, max 41.6 amps (says to fuse it at 50 amps). It also says
taper wound - which is odd, I don't see any taper to the core or the
windings. It is however very non-linear. The maximum inductance is 54 mh.
The point where I had it set was only 5 mh. Now I find it really odd that
trying different settings (probably over a range of 3 mh to 30 mh) appeared
to show no difference in coil performance. There is something to learn here
but it isn't real obvious to me. It seems that some inductance is required
but the actual amount used is not critical - and why do welders seem to cause
problems that variacs don't? I even measured the inductance of the welder
that I originally used and remember it to be in this range.
Ed Sonderman