Pages: 1 [2] 3   Go Down
Author Topic: HV supply ideas  (Read 1844 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
God Member
*****
Karma: 7
Posts: 647
"In this house, we obey the Laws of Thermodynamics" Homer J. Simpson
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Here is a "big boy's power supply" 200-300kV.


I think the bloke is insane, he seems to know what he is doing but I would not be surprised if his vlog stopped abruptly one day.

Everybody's resistance is different and changes quite a lot e.g. if your fingers are a bit sweaty.
So what you might be lucky and get away with one day might kill you the next.

The spasm caused by an HV shock might make you bite your tongue, tear muscles, or cause you to break bones as you hit things and fall over.

I got a belt of a TV crt tube once. It was unplugged, but still holding a charge and was something I am happy to avoid repeating.
Logged

New Jersey
Online Online
Faraday Member
**
Karma: 67
Posts: 3684
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

OP - pick a field in which you have expertise. Think of the most foolish and irresponsible thing a novice could do in that area. Imagine the advice you would give such a person. Follow it.
Logged

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Perhaps I will start a bit smaller maybe 10kv, hv seems to get expensive quick and im not that rich
Other than a flyback transformer and a hv transformer would an electronic fluorescent ballast provide good starting point to feed to a multipler?
and I understand the safety concerns, I play around in a locked shed that only I have access to, and im an electrician which doesn't qualify me in HV at all but im pretty good with being safe, 240v isn't fun to get shocked with so I imagine 24kv would suck
Logged

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

So I guess for the arduino control tho, it would be easier to measure the input voltage/current and calculate the output voltage? I don't even know of a common multimeter that goes above 500v for me to test if the arduino was properly measuring HV
Logged

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Ok so for starters I used a 555 timer driving a 2 stage multiplier off 12 v and I got 38, so not bad so far but that's at 2.2Mhz, how hard do you think it would be to have a higher voltage version using some 600v mosfets for switching directly rectified 240v mains?
Logged

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 302
Posts: 26250
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Before you go much further, you probably want to double-check the insulation rating of any wire you're using.
You may be surprised, but I hope not shocked.
EHT can take very odd paths - beware.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

On the lower voltage side 240vac I know im good with that, but I doubt on the other end its fine so im gonna keep those wires short and away from everything else, and the circuit ill probably leave in mineral oil so it doesn't flash over and destroy itself
Logged

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 302
Posts: 26250
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Make sure all your joints are nice and smooth too, no point radii.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

United Kingdom
Offline Offline
Tesla Member
***
Karma: 224
Posts: 6614
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If you switch directly from rectified 240v mains then the output won't be isolated, making it even more dangerous - unless your design includes an isolating transformer. Also, how will you adjust the output voltage?
Logged

Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I was thinking if I could measure the output somehow directly or indirectly, I could change the duty cycle to change the voltage, basically changing the vrms input to the multiplier
Logged

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

And I think im gonna add a current limit resistor before the multipler for safetly
Logged

United Kingdom
Offline Offline
Tesla Member
***
Karma: 224
Posts: 6614
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I was thinking if I could measure the output somehow directly or indirectly, I could change the duty cycle to change the voltage, basically changing the vrms input to the multiplier

Only if you have an inductor in the circuit, for example an L-C smoothing network, or the transformer in a flyback converter. Otherwise, the rectified output voltage will follow the peak-to-peak input voltage.
Logged

Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Dallas, Texas
Offline Offline
God Member
*****
Karma: 31
Posts: 887
Old, decrepit curmugeon
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I have built a variable high voltage DC supply that is in this range for purposes of creating a very high speed flash ( a few microsecond duration).  The techniques are not difficult, but my supply is not regulated, which would add a lot of complexity.

Basically I use a variac to power a neon sign transformer, which then goes to a voltage multiplier circuit.  The neon sign transformer, obtained from ebay, was one of the cheaper components of the device.  Even the wire, not to mention the diodes and capacitors, are expensive when dealing with these voltage/current levels.  I couldn't find reasonable connectors, so I ended up machining the connectors from scratch...

Again doable, but not a simple project.  Also, as has been mentioned, these are considered lethal power levels.
Logged

New true random number library available at: http://code.google.com/p/avr-hardware-random-number-generation/

Current version 1.0.1

Dallas, Texas
Offline Offline
God Member
*****
Karma: 31
Posts: 887
Old, decrepit curmugeon
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

So I guess for the arduino control tho, it would be easier to measure the input voltage/current and calculate the output voltage? I don't even know of a common multimeter that goes above 500v for me to test if the arduino was properly measuring HV

When I built my  circuit I picked up a high voltage probe for my multimeter that permits it to measure up to 50kV.  Cost about $75 on ebay...
Logged

New true random number library available at: http://code.google.com/p/avr-hardware-random-number-generation/

Current version 1.0.1

Offline Offline
Edison Member
*
Karma: 5
Posts: 1730
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Yikes that's expensive,
I was looking on ebay and 20$ isn't that bad for it, but I was gonna try and make the frequency as high as possible(probably limited by the mosfets or igbts I get) to allow me to use smaller size capacitors and less ripple
now for that inductor, I guess since its high frequency it wont have to be too large right? Perhaps in the range of something small air cored?
Logged

Pages: 1 [2] 3   Go Up
Jump to: