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
dieter.boeckeler@xxxxxxxxxxx wrote:
>Hi Coiler,David and Stefan,
>I´m at the TCML a long time ago,but mostly as a reading member.
>
>you don´t need big variacs to control your pole pig.
>
>There is a device called "phase shift controller"with thyristors.
>I drive my 15kVA TC with this devices,here we have 400V/50Hz,but it works also at 240V/60Hz.
>
>for 3 phase 95Amps the weight will be less than 15kg,the most weight is the heatsink for the Thyristormodules.!
>It´s used two control galvanic bath,windmills,transformers and very large motors in ships and so on.
>
>You can get thyristor-powerblocks over 500A.
>
>You should take thyristors with a voltage rating 3-4times the supply voltage.
>
>for example TT150N16 (150A/1600V).
>
>but you need a current limiter also.I´ve tried an electronic current-regulator,but it´s not fast enough.
>
>best regards
>
>alex
>
>
>
>-----Original-Nachricht-----
>Betreff: Re: [TCML] 30kVA 3-Phase Variac
>Datum: Wed, 10 Sep 2014 16:31:33 +0200
>Von: "Teslalabor" <teslalabor@xxxxxxxxxxx>
>An: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>
>Hi David,
>
>it was "a little of nothing".
>This variac was used in a theatre for dimming nearly hundred light bulbs.
>Because the bulbs wasted a lot of (expensive) energy, the whole system was
>replaced by LED systems, so the variac was not needed any more. So I took
>the opportunity :-)
>Yes, this variac is called a "columnar variac". Here in germany we have both
>types, also the circular shaped units. I have another columnar variac, which
>I will use in my current DC resonant project. This isn't even an
>autotransformer, it has separated primary and secondary coils:
>
>https://www.youtube.com/watch?v=5EKyaMFbCP4
>
>And here is another circular shaped high power 3-phase variac in my variac
>collection: It makes 0-440V @ 32Amps per phase (24kVA) and of course can
>also be pushed far behind this powerlevel
>
>https://www.youtube.com/watch?v=798JN1ZgHq4
>
>Regards,
>Stefan
>
>
>----- Original Message -----
>From: "David Rieben" <drieben@xxxxxxx>
>To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>Sent: Tuesday, September 09, 2014 7:08 PM
>Subject: Re: [TCML] 30kVA 3-Phase Variac
>
>
>> Wow! Nice find. Did you have to come off a king's ransom to score this
>> beauty or were your able to get it for "a little of nothing"?
>> I see it's linear, as opposed to the more common circular shaped style (at
>> least here in the US they are).
>>
>> David
>>
>>
>> On Tuesday, September 9, 2014 6:31 AM, Teslalabor <teslalabor@xxxxxxxxxxx>
>> wrote:
>>
>>
>>
>> Hi all,
>>
>> just wanted to show you my new 0-400V high-power variac, made a video of
>> it.
>> It's a motor driven 3-phase variac with a power rating of 30kVA. It has a
>> nameplate rating of 45A per phase and can make twice the power for 2
>> minutes
>> (90Amps per phase, 60kVA).
>> 2x2 Contactors per phase and so it even has balancing chokes between each
>> pair of contactors on each phase. The contact-surface below them is silver
>> coated, so it has a dark colour.
>>
>> Video: https://www.youtube.com/watch?v=U5No4VBoM9A
>>
>> Regards,
>> Stefan
>>
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