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Re: [TCML] 30kVA 3-Phase Variac



Hi Jason,coiler,
do you have a RC damping over the thyristor?
the gate-wires have to be drilled together and should max.12"long..
the electronic regulator needs a few sine waves to regulate the current,thats to slow,if the regulator time is set
 faster,the load (transformer) is swinging up and down.
so i´ve an inductive ballast,also.
i also own a 18kV/2,8kJ cap,and at the moment 480kV/100J (later 1MV /200J)marx generator (ZVS Mosfet driver)
 and a 600kV VDG (PWM controlled)the static field of the VDG raises yor hair around 2,5metres in distance ,the PWM controller
 is  at the base of the VDG (1,4metres distance,o.k. in metal earthed case) never with problems.
My main problem i´ve with this devices,the LCD meters are often defect,if firing.
So i use analog  µA meters with 1gohm resistance.
best regards
Alex

-----Original-Nachricht-----
Betreff: Re: [TCML] 30kVA 3-Phase Variac
Datum: Thu, 11 Sep 2014 23:39:19 +0200
Von: Jason Johnson <jasonmsusolar@xxxxxxxxx>
An: Tesla Coil Mailing List <tesla@xxxxxxxxxx>

I have used smaller phase angle SCR controllers from Eurotherm (TE10-A;
http://www.eurotherm.com/products/power-control/power-controllers/te10a/).
I have a blown up one right here that died in cap bank charging service...
(though admittedly the neighboring 600 kA discharges from the pulse cap
bank are a little extreme in terms of EMI sources).

They are really slick if you have external current limiting. They won't
limit current by themselves (as you mentioned it only replaces the variac,
not the ballast).

If the price is right, they are definitely viable for TC use, you just have
to take a bit of care in where your signal wires are routed (perhaps more
so than with old school iron and copper).

Jason

On Thu, Sep 11, 2014 at 11:36 AM, dieter.boeckeler@xxxxxxxxxxx <
dieter.boeckeler@xxxxxxxxxxx> wrote:

> Hi Jason,coiler,i know about emi,but the controller i used for the phase
> shift is called Thyro-A/Thyrovar (from AEG.)
> This device had passed the requirements for nuclear power plants,and it´s
> emi testet.
> Our company uses this type of controller to crontrol voltage of 800V at a
> load of 320A 10khz for plasma nitriding in hardening shops .
> The gate cathode current needet to turn on a thyristor is over 1A (typical
> resistance around 10ohms),but if you use IGBT´s (DRSSTC´s) they don´t need
> current to turn on,only (less than 20V) voltage,like a capacitor.That´s way
> more sensitive.But if designed well,a DRSSTC performs better than a RSG
> Coil.The phase shift controller replace only the variac,like a dimmer at
> home,but for way more power and without weight..My 15kVA TC and a bigger
> around 30kVA (from a friend) use this controller without problems.
> best regards
> Alex
>
>
>
>
>
> -----Original-Nachricht-----
> Betreff: Re: [TCML] 30kVA 3-Phase Variac
> Datum: Thu, 11 Sep 2014 15:21:24 +0200
> Von: Jason Johnson <jasonmsusolar@xxxxxxxxx>
> An: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>
> "problematic" can be an understatement.
>
> A coworker and I once used a solid state relay to control the charging
> transformer on a 1 kJ cap bank. While debugging the trigger system
> (ignition coil plus light dimmer trick), EMI from the trigger transformer
> was turning the stupid solid state relay on (this was a 3-32 VDC control 30
> A brick type SSR). This managed to charge the cap up to lethal voltage
> without us knowing it (there is a shorting relay in the permanent setup,
> but this was a lashup). When I poked the cap terminals with a multimeter
> there was a loud bang and a dead meter. I was incredibly lucky that it was
> the multimeter that was dead and not me!
>
> We figured out what was happening and immediately replaced the SSR with an
> old style contactor. Problem solved.
>
> Be careful, and always plan redundant safety measures when working with HV!
> One mistake can be your last.
>
> - Jason
>
>
> On Wed, Sep 10, 2014 at 1:03 PM, David Rieben <drieben@xxxxxxx> wrote:
>
> > Hi Alex,
> >
> > Yes, I've heard of electronic phase shifters for controlling big powered
> > AC loads, but I've also heard they can be rather problematic when trying
> to
> > control an EM "dirty" load like a SG Tesla coil. I know the neon sign
> > industry has gone more with these for their bombarding operations instead
> > of massive variacs, but then again, a bombarder transformer cleaning
> down a
> > neon tube is not an EM or RF dirty environment.
> >
> > David
> >
> >
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