high dc voltage buck convertor

[harp]

I watch this video
https://www.youtube.com/watch?v=Lh6YATitN9k
and wonder is possible on simple way to convert high dc voltage (over 60000v, low amps) into usable one, eg 12v dc, some amp? Circuit?

[eccerr0r]

Re: high dc voltage buck convertor

capacitors have limited capacity.

60000 volts at 1mA for 1 second is far far far less energy than 1.2v 2A for 1 hour (NiMH AA cell).

[harp]

Re: high dc voltage buck convertor

Yes, but my scope is on technical point of view not economical or other...

[petehall347]

Re: high dc voltage buck convertor

you might have to chop it into an ac pulse first then use a big transformer like a substation .

[harp]

Re: high dc voltage buck convertor

How to chop such high dc voltage, any specific technique to avoid arcing or burning?

[CapLeaker]

Re: high dc voltage buck convertor

I think you have a better chance of getting free energy underneath HV power lines.

[harp]

Re: high dc voltage buck convertor

... and you know how to chop high dc voltage...?

Free energy is all around, just get solar panel and soon it give much more then AA... :
But, question is about converting very hv dc into usable one, nothing else...

[eccerr0r]

Re: high dc voltage buck convertor

The question remains: what is the source of the high voltage.
There is NO natural source of sustained high voltage that will sustain over long periods of time, it's always short duration and quite unusable.
Until you get a long duration high voltage source this is looking for a solution that's looking for a problem that doesn't exist. The only long duration high voltage source is seen at power plants and substations, and that has already been worked out, and they have been doing both AC and DC for years - using transformers and high voltage IGBTs/SCRs/even thyratrons when they were best...

[CapLeaker]

Re: high dc voltage buck convertor

... and you know how to chop high dc voltage...?

Free energy is all around, just get solar panel and soon it give much more then AA... :
But, question is about converting very hv dc into usable one, nothing else...

There are a few vids on YouTube. Many years ago I built such a device and tried it on a nearby TV and Radio transmitter site and it worked. As far as I remember, there was even an IC that recovered power through nearby RF. I had used just something common off the shelf as rectifier. However the power output wasn’t enough to light a small LED without a super capacitor. To tell you the truth, you are miles ahead, charging a battery using the old land line.

I would transform High Voltage AC to lower AC then rectify it. It all depends on how much V and mA we are talking about here.

[harp]

Re: high dc voltage buck convertor

So, hypotetic, if I get big Leiden jar(s) of 10nF and charge up to say 100000v, so it is pure DC, how to get AC from that or lower voltage by any method? There in the jar is no RF, nor AC component, and she got much power inside it.

[eccerr0r]

Re: high dc voltage buck convertor

So, hypotetic, if I get big Leiden jar(s) of 10nF and charge up to say 100000v, so it is pure DC, how to get AC from that or lower voltage by any method? There in the jar is no RF, nor AC component, and she got much power inside it.

As said, the leiden jar is just a capacitor. Also you're not getting 100kV because the electrodes are too close and will arc. So you say separate them, well now your C will go down so you're screwed. Also 10nF is ridiculously optimistic as it is. Likely you'll be lucky to get a few pF of capacitance.

Even if you could get a 100kV 10nF capacitor (this would physically be huge) this is on the order of double digit joules. Compare to a 2Ah 1.2V AA NiMH cell which is 8000 joules. I'd take the AA battery!!!

(At least you're indicating this capacitor is pure power. Yes it has power, but what it lacks is energy.)

[harp]

Re: high dc voltage buck convertor

Ok, I get it
Thanks!

[stj]

Re: high dc voltage buck convertor

build an inductive coil tuned to the frequency.
it may be DC but i bet they didnt smooth it after the rectifiers.

[eccerr0r]

Re: high dc voltage buck convertor

Any charge stored in a Leiden jar/capacitor will be pure DC.
I was initially thinking that given enough of an inductor you could make it resonate as an LC-tank but the Q factor would have to be designed arbitrarily high else you'd lose those few joules of energy stored in it... and of course another winding on the inductor to tap the energy off at lower voltage.
Of course you can't charge the jar while it's oscillating so that's a different problem, but ultimately the amount of energy stored is so little it's not cost effective to extract this energy as that little energy - some will be wasted during conversion too - will be even less energy on the output.