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Stepping down 200kv to 1kv

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Andy

Thu Aug 15 2013, 09:08AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Posts: 874

Hi, What would be the best way to step down 200kv ,1amp square wave to 1kv, 200amp. Was thinking about voltage divider, with transformers in parallel. Would a buck circuit work, what values would you use?

Thanks for any input

Steve Conner

Thu Aug 15 2013, 10:09AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

The best way depends on the application. In most applications the best way would be to avoid using 200kV input in the first place.

You said the input is a square wave, that implies AC so you could "simply" use a transformer to do the stepping down. I say simply in quotes because designing a 200kV, 200kVA, 200:1 transformer isn't really what you would call simple. Oil or SF6 insulation would help. Depending on the frequency, it will end up somewhere between the size of a washing machine and a car.

Dr. ISOTOP

Thu Aug 15 2013, 10:11AM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

The "easiest" way would be a 200:1 200KVA transformer, but that's not saying much...
Application? It's hard to give concrete advice without more details.

EDIT: Ninja'd by Steve Conner

Andy

Thu Aug 15 2013, 10:50AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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If it is 1khzand you were trying to make it as cheap as possible, would structure steel 10cm by 2cm as wire work, if you use mumetal for the core?

Application? It's hard to give concrete advice without more details.

Just a thought experiment :)

Steve Conner

Thu Aug 15 2013, 05:21PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

No, the most cost effective materials for transformer making are, believe it or not, copper or aluminium for the windings and iron (or ferrite above a few kHz) for the core.

Even if a mu-metal core would somehow magically make steel work as windings (it wouldn't) mu-metal is so expensive that it would cancel out the cost saving from not using copper windings.

Andy

Thu Aug 15 2013, 08:54PM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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If the voltage is steady state dc, would wiring up a transformer like a inductor in series, with the transformer 1:200, would applying a square wave of 1kv to the secondary make the dc steady state square wave,on the primary?

___________WWW____________________
|................... MMMM...........
____ ...............|........|.............
---....................dc square wave 1kv
|200kv....................................
|..........................................
___________________________________

Avalanche

Fri Aug 16 2013, 10:35AM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Andy wrote ...

If the voltage is steady state dc, would wiring up a transformer like a inductor in series, with the transformer 1:200, would applying a square wave of 1kv to the secondary make the dc steady state square wave,on the primary?

___________WWW____________________
|................... MMMM...........
____ ...............|........|.............
---....................dc square wave 1kv
|200kv....................................
|..........................................
___________________________________

I tried to reply to that last night for a challenge, but it just made my head explode

I think the answer is "no".

However, I think the closest thing to what you're trying to describe is either a 'forward converter', or a 'buck converter'.

There are many of these converter topologies already in existence, so the chances are anything you think up will already have a name. There's a PDF here

which describes some of the most common ones.

Andy

Fri Aug 16 2013, 07:31PM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Posts: 874

Thanks Avalanche for the link, being thinking about converters but I don't think any switch will handle 200kv.
The dc square wave would be lower amps than what the dc source is, but the same voltage.

Sulaiman

Fri Aug 16 2013, 07:50PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

Is this a real problem or just a thought experiment?

If real, what are;
rise time, on time, fall time ,off time and source impedance?

Andy

Fri Aug 16 2013, 08:10PM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874

rise time 1ns, ontime 1ms offtime 1ms, source impedance 1Mohm for the square wave dc source, the inductance of the primary 1mH, the inductance of the secondary 1H.

EDIT
The core will be 40cm*40cm of steel, 0.0002(5000hz), with 100turns(primary), at 50kv, with the secondary of 10,000turns.

Thanks

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