Re: Saturable Reactor Waveforms

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Just Justin <rocketfuel@xxxxxxxxxxxxx>


I once got a 20A variac in a cardboard box w/no foam...

the box was pretty "thrashed", but the variac has been "working fine"!


justin


On Tue, Mar 14, 2006 at 07:00:34PM -0700, Tesla list wrote:
> Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
>
> Well, so much for my immediate efforts to make a
> MOT-based SR; my order of eight MOTs arrived today
> severely damaged due to an abominable packing job.
> I'll refrain from indicating who the seller is until
> I've found out whether they're willing to offer any
> kind of remediation.
>
> Pretty much ruins my week.  And it's only Tuesday!
> Sheesh...
>
> Regards,
> Aaron, N7OE
>
> --- Tesla list <tesla@xxxxxxxxxx> wrote:
>
>  > Original poster: "J. Aaron Holmes"
>  > <jaholmes@xxxxxxxxxxxxxxxxxx>
>  >
>  > Yes.  I was planning on doing this, but for
>  > different
>  > reasons (somebody suggested last week on hvlist and
>  > a
>  > choke in series with the control might be needed in
>  > order to eliminate harmonics).
>  >
>  > Regarding the additive/subtractive flux, however, I
>  > would hope to see things cancel out.  With the
>  > control
>  > sides of the transformers in a pair being in phase
>  > with each other, it seems like the control-induced
>  > flux aids each transformer in opposite half cycles.
>  > What this means in practice I'm not sure of, but
>  > will
>  > endeavor to find out when my transformers finally
>  > arrive.  It may have more of an impact in cases
>  > where
>  > the MOT primaries in a pair are in series rather
>  > than
>  > parallel, too, because if it influences the
>  > impedances
>  > of the primaries in opposite half cycles, this would
>  > seem likely to translate into much higher AC on the
>  > control side by basically turning the pair into a
>  > variable voltage divider.  ...but still, all
>  > speculation.
>  >
>  > Anyway, you're right, there is some very worthwhile
>  > investigation to be done.  Carl already has a bunch
>  > of
>  > stuff hooked up, and may be able to beat me to it.
>  > Otherwise, I will definitely be looking into this.
>  >
>  > Regards,
>  > Aaron, N7OE
>  >
>  >
>  > --- Tesla list <tesla@xxxxxxxxxx> wrote:
>  >
>  >  > Original poster: "S&JY"
>  > <youngsters@xxxxxxxxxxxxxxx>
>  >  >
>  >  > To SR constructors,
>  >  >
>  >  > I have been reading with much interest your
>  > success
>  >  > using pairs and paired
>  >  > groups of transformers to make SRs.  If one of
>  > you
>  >  > has made scope photos of
>  >  > the resulting output waveform into a resistive
>  > load,
>  >  > please post them where
>  >  > we can view them.  A series of photos at
>  > increasing
>  >  > DC control voltages
>  >  > would be interesting.  I am especially interested
>  > in
>  >  > the effects on output
>  >  > waveform symmetry vs DC control voltage.  Seems
>  > like
>  >  > in half a cycle, the
>  >  > magnetic fields would be additive, causing core
>  >  > saturation sooner than with
>  >  > the other half cycle where the magnetic fields
>  > would
>  >  > be opposing and would
>  >  > somewhat cancel out.  Thus the output waveform
>  > would
>  >  > not be symmetrical.
>  >  > Or, because of the use of pairs of transformers,
>  > do
>  >  > the asymmetries from
>  >  > each individual transformer balance out when they
>  >  > are connected in series?
>  >  >
>  >  > Thanks,
>  >  > --Steve Y.
>  >  >
>  >  >
>  >  >
>  >
>  >
>  >
>