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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