It used to be that nearly every home had at least one decent high-voltage power supply. Of course, it was dedicated to accelerating electrons and slamming them into phosphors so we could bathe ourselves in X-rays (not really) while watching Howdy Doody. These days the trusty tube has been replaced with LEDs and liquid crystals, which is a shame because there’s so much fun to be had with tens of thousands of volts at your disposal.
That’s the impetus behind this inexpensive high-voltage power supply by [Sebastian] over at Baltic Labs. The heavy lifting for this build is done by a commercially available power supply for a 50-watt CO2 laser tube, manufactured — or at least branded — by VEVOR, a company that seems intent on becoming the “Harbor Freight of everything.” It’s a bold choice given the brand’s somewhat questionable reputation for quality, but the build quality on the supply seems decent, at least from the outside. [Sebastian] mounted the supply inside a rack-mount case, as one does, and provided some basic controls, including the obligatory scary-looking toggle switch with safety cover. A pair of ammeters show current and voltage, the latter with the help of a high-voltage resistor rated at 1 gigaohm (!). The high-voltage feedthrough on the front panel is a little dodgy — a simple rubber grommet — but along with the insulation on the high-voltage output lead, it seems to be enough.
The power supply’s 30 kV output is plenty for [Sebastian]’s current needs, which from the video below appear to mainly include spark gap experiments. He does mention that 50 kV commercial supplies are available too, but it would be tough to do that for the $150 or so he spent on this one. There are other ways to go, of course — [Niklas] over at Advanced Tinkering recently shared his design for a more scratch-built high-voltage supply that’s pretty cool too. Whatever you do, though, be careful; we’ve been bitten by a 50 kV flyback supply before and it’s no joke.
Anyone know a source for adjustable HV power supplies that go from ideally 0.5kv to 12kv or so?
Depending on your needs and ability, a nice HV can be made from a Variac, neon sign transformer and handful of high voltage rectifiers.
Check Ebay. There’s plenty of supplies there.
Some of the switchers are commercial grade with a 24Vdc input and feature an adjustable output.
Since an output current wasn’t specified, I’d expect 10mA to be sufficient for most applications.
Have you looked into building voltage multipliers?
Perhaps Variac and isolation/setp-up transformer feeding a Cockcroft-Walton multiplier would do. The cool thing about such a voltage multiplier is that the breakdown voltage of the individual diodes and capacitors can be a small fraction of the total output voltage.
Of course, playing with high voltage is dangerous because of the ease with which you can become an accidental conductor when the insulation (air, perhaps) between you and the source of potential unexpectedly fails.
To be fair, if you use many stages of small value diodes and capacitors, the impedance at 60Hz will make the multiplier voltage sag at almost any current, including possibly the stray discharges at rest.
Hi all,
Would anybody be here be able to help me design an adjustable DC power supply 0-15kv and it needs to be able to give 5A max if needed.
It has to be a very clean DC wave, 220v input, adjustable 0-15kv output.
I’m happy to pay somebody for assistance, happy to do a zoom meeting or just communicate over social media etc.
Thanks
Denver
Yuk.
Routing the HV line to the poor front panel meter is not something I would dare to do. I would use a decently isolation-rated optocoupler to do the job, and keep the optocoupler inside the HV subsystem.
I saved a bunch of flyback transformers from old monitors that I recycled. maybe this is the kick I need to build my own HVPS.
I also have a few microwave transformers, lower voltage but overall way more power. I got to have an unrecognized need somewhere!
Hopefuly not an unrecognized need to die. Those microwave transformers can _easy_ kill you if you make one single mistake! Somewhere on Youtube there is a video from Bigclivedotcom about this.
Up-voted. I was going to write essentially the same response.
Be careful cz microwave transformers can deliver around 500 tom100ma, more than enough to kill you! I have read pf fatalities involving people doing high voltage wood burning with oven transformers.
I have drawn over 36 amps from a 120v outlet before I shit myself and turned it off. 2 amps at 2200v is easily doable with these death machines.
I’ve had a laser engraver power supply go bad, and the characteristics of “go bad” was that the laser was on at a low level all the time.
Specifically, with the laser “not cutting” by panel control it would etch a small line into the stock while you were positioning it under the laser head. This was with the lid open and a functioning interlock switch.
Perhaps the final stage power FETs got zapped and were conducting when they should have been off? I suspect the low-level power output would become progressively higher output with continued use.
Anyway, I need a high-voltage supply for one of my projects, and after the incident I’m a little gun-shy of using laser power supplies for that purpose.
Does anyone have any more info on how these things fail? It seems like at this level of danger you should take the failure modes into account with the design.
(My professional life was designing aircraft instruments and we always took the failure modes into account. The default was fail “safe”, but the laser supply mentioned managed to fail “dangerous”. And no, I’m not a safety nanny: I’m all in favor of doing dangerous things, just in a sensible way.)
One of the previous articles on high voltage (https://hackaday.com/2024/01/18/lessons-learned-from-a-high-voltage-power-supply/) mentions using a pneumatically actuated switch and indicator lights. I’d treat the laser supply like anything else and just consider it unsafe when the power lights are lit, regardless of the supposed safeties.
That said, if that’s what these supplies do, maybe you also want something to short the power into as a second protection.
do the interlocks break the primary power directly or depend on a low voltage control circuit?
FWIW -I have seen old (early ’90’s) “solid state relays” for 24V AC controls fail in what I call “high impedance” (feel free to correct the terminology) mode that continue to conduct at a level just enough to create unpredictable results in control devices.
Also have run across (in US 240V) where to save a few pennies hvac equipment went to a single line break relay probably ok for European system but a little scary on US system
The interlocks are in series with the power supply ENB input, which we believe is digital, and tied to ground. So when the interlock is open there’s no way for ENB to go high, but the supply is powered up the entire time.
We didn’t think it was an input issue because we couldn’t think of a way that a digital input could go high in such a way to turn the output on a tiny amount.
I would be happy with 6.3v + 300v + 550v + 850v
Stephen G7VFY
Wouldn’t you also need 5V for the rectifier filament?
I don’t want to be bad, but can you explain what is the “hack” of buying a HV supply and using it?
He hacked a few holes in his newly bought case…
“The power supply’s 30 kV output is plenty for [Sebastian]’s current needs”
Yes very funny
Having repaired one of those PSUs recently, I can confirm that the enclosure is the heat sink, and that the blue foil can come off. It’s just there to protect the metal from scratches during production.
If someone wants to just muck about with arcs eBay has a flyback and zvs for only around twenty quid. No nice box, and dials but they’ll ionise 2cm of air. They’re rather impressive with 30v and 10 amp supply.
Be careful if your ground is loose the meter device etc is full potential.
“by VEVOR, a company that seems intent on becoming the “Harbor Freight of everything.” ”
Yeah, vevor is everywhere. My house is heated with a vevor diesel heater but I had to mod the fuel pump and the exhaust to make it livable. It’s so noisy when stock. If the vevor drill bit sharpener wasn’t so crazy expensive, I would have bought it already. It’s 260 euro’s. I might buy it this year.
Location: a classroom for TV theory. A CRT type TV is in front of each student.
Main character: one student is bored.
Student places insulating mat under his chair, and uses anti static strap to hook himself up to 30kV power supply. Switches on, allows time for his body to build up a charge.
Disconnects, then leans over to adjacent student – and taps them on the earlobe.
Result: bodily damage, and career ending repercussions.