RE: saturable reactor vs choke

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jack King" <ekklekktikk@xxxxxxxxxxx>




> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: RE: saturable reactor vs choke
> Date: Tue, 18 Apr 2006 17:13:04 -0600
>
> Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
>
> Hi Gerry, Steve, all,
>
> If you can come up with a silicon based solution that is comparable to the
> 375 lbs of copper and iron in my truck, I'll be cutting the copper off for
> the scrap yard post haste!

...Well I wouldnt wheel it to the curb just yet...I have yet to find 
a suitable firing card and triacs to approximate what a S-R and old 
slide chokes do - I mostly roll such systems for NEON people, so our 
HV transformers arent presented with a big cap and spark gap on the 
end...but hey, silicon steel and copper fetch good money these days 
(and then it's of to Mexico or China)

> I'll run it up to 15KVA on hot water heater elements and measure the current
> draw verses the control voltage. It will be interesting to see how much
> linearity it actually has. It would be worth buying one more element I
> suppose (4500w/220v) which would run very close to the spec plate. Is there
> anything you would like me to test? I will be scoping the wave form.

You may want to parallell a dumb 0-300 V meter on the load, It would 
be interesting to see how attenuated the volatge is at startup with 
your load parked on it.

> I will
> over kill the DC by a few amps and regulate it.

I think your gonna have MASSIVE heat from the elements before you get 
near 90 volts dc...Just a hunch from past experiments (but mine have 
been with "240" v units )...


> It will be interesting to study what happens on a Jacob's ladder. I'll run
> the pig up to 2x 5kva max.

THAT sounds like fun!

> We will know more about the inductive/current behavior of this beast by next
> week. Be assured that I have no desire to plot the full 90 volts control on
> my pig since I want to be on the conservative side of whatever knee there
> is. My neighbors would not like a brown out. There are six of us on one pig
> which has blown up before.

Yeah, your 5 kva pig wouldnt like you much...and hopefully you werent 
the culprit on the last pig-popping!


> Silicon, Germanium, Fiber, it's all good. Leave me the copper, silver, and
> gold!
>
> Jim Mora

ANxious to here of your findings Jim...and I may be able to help you 
find some suitable smaller saturable reactors...I run into them in 
things like old induction heaters and forklift chargers all the time!

Jack



> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Tuesday, April 18, 2006 1:23 PM
> To: tesla@xxxxxxxxxx
> Subject: Re: saturable reactor vs choke
>
> Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
>
> I bet all cores have a less than ideal BH knee meaning there is some
> softness to it and I suspect that this helps with the "infinite"
> current problem.
>
> Gerry R
>
> >Original poster: Steve Conner <steve@xxxxxxxxxxxx>
> >
> >Hi Gerry,
> >
> >>What happens if the load is a PIG where the SG is firing???  It
> >>seems like the load wont limit the current then
> >
> >I think you just have to hope that the saturable reactor has enough
> >stray inductance left over, even once it's saturated, to ballast the
> >pig enough that the spark gap can quench. My gut feeling is that it
> >probably would work fine. From reading the archives, it seems people
> >successfully use ungapped variacs as ballasts, and these probably
> >run in saturation most of the time.
> >
> >When I really think about it, it seems that a small ballast choke
> >sized to run the maximum power you want, combined with a pair of
> >back-to-back SCRs wired like a huge lamp dimmer, would function
> >identically to a SR, but be a good deal smaller and lighter. But i
> >guess we want to keep the silicooties out :-<
> >
> >Steve
> >
> >
> >