Sciencemadness Discussion Board - High Voltage power supply

High Voltage power supply

HammerOfLight - 29-5-2010 at 20:41

I've constructed a high voltage power supply, using a 555 timing ic, a lm741t voltage regulator, and a 2n3055 power transistor. I built a basic, filter voltage regulator that will allow me to control the voltage down to .01 volt increments. The output then goes into a 555 circuit setup as an astable oscillator that is filter to prevent noise, and runs from 200 Hz to 40 Khz in square wave output with a duty cycle of 50%-90%. A 2n3055 transistor will supply a current boost to an ignition coil with a 1N4004 diode across the primary to prevent negative kickback from hitting the transistor. I'll use a 1-100 Vdc meter with a voltage divider to get readings of 1000-100000 volts on the output. I am simply putting a variable resistor on the supply to the transistor to limit the current to the primary on the ignition coil.

12AX7 - 30-5-2010 at 02:05

Yuck.

There are better ways. Waaay, better ways. Like for one thing, forget 741 and 3055 ever existed. There are cheaper, better alternatives.

Did you check out e.g. UC3842 + STP26NF10?

Tim

HammerOfLight - 30-5-2010 at 09:10

Sorry, I am unfamiliar with those chips, I grew up with the 555, the 741 and the 74xx regulators, and 2n series of transistors. Luckily I don't need allot of current to run the setup, otherwise I would have designed a different power regulator. I'll investigate those chips though.

D4RR3N - 10-6-2010 at 10:42

Here is one I built a while back, I used a plasma globe driver at around 25-30kv as the input.

CRT.JPG - 175kB

quicksilver - 20-6-2010 at 08:41

@ D4RR3N :

That's a really nicely done job. I like the frame for all those doorknobs! Plasma PSU are a good thing. I bought one as surplus that had a dual unit (I can't put them in series however) from Surplus Sales of Nebraska and each puts out 11k. I may copy your design I like it so much. It's simple and that always appeals to me.
It must have cost a lot if you had to BUY those doorknob caps!

12AX7 - 20-6-2010 at 11:49

One suggestion: if you want any more than static electricity on the output, you should assemble the capacitors in a pyramid. Use large caps on the bottom, smaller towards the top. Ideally, each stage should be substantially smaller than the proceeding stage, but this implies exponential growth; in practice, a simple "right triangle" construction might be used instead, where you parallel e.g. 20 capacitors for the first, then 19 for the second, ..., then 1 for the 20th at the top.

In principle, the diodes should also be rated accordingly, but as the current at any stage is going to be well below ratings, this won't be a problem. For a really big one (like, kilowatts), it might need consideration.

Other approaches include very well insulated transformers. You could make a series of bank wound transformers with a well insulated, single turn primary, looping that turn through say 10 transformers, and stacking all the outputs. (This works for AC or DC, but DC is preferred, as the capacitance of each transformer is magnified by the total turns ratio!)

Also, resonators (think Tesla coil) have value, though you'll have a hard time finding diodes to make DC. I don't know that anyone ever made a 1MV vacuum diode, which would be the most practical approach. The highest voltage rectifiers from TVs go up to only 60kV. On the other hand, the total voltage drop for a stack of e.g. 20 x 50kV silicon diodes wouldn't be any worse than a 20 stage C-W multiplier, so you'll end up with the same efficiency either way (possibly better efficiency because you aren't necessarily drawing such large current spikes when charging capacitors).

Tim

White Yeti - 21-10-2011 at 17:16

If I really wanted a HV source, I would have sabotaged a CFL. CFL transformer circuits can ramp the voltage up to about 14,000V. The output can then be fed into an amplifier that can easily reach the 100KV range.

I personally don't like to mess around with high voltage, so I don't know if this really works. I know this is mad science, but a home built high voltage supply is a little too much. I don't think my cardiovascular system will appreciate an accident, or a slip up.

watson.fawkes - 21-10-2011 at 17:42

Quote: Originally posted by White Yeti

CFL transformer circuits can ramp the voltage up to about 14,000V. The output can then be fed into an amplifier that can easily reach the 100KV range.

I personally don't like to mess around with high voltage, so I don't know if this really works.

(1) What kind of amplifier is that? (2) No, you really don't know.

HV is dangerous. Posting random yammerings about isn't the most responsible thing in the world.

White Yeti - 21-10-2011 at 18:05

Quote: Originally posted by watson.fawkes

(1) What kind of amplifier is that? (2) No, you really don't know.

I know what a voltage amplifier is, in fact I use one very often to boost voltage from certain homemade batteries. If I wanted to experiment with high voltage, one of the first amplifiers I would have built would be something along the lines of a Marx generator. There are other high voltage circuits I could mention, the Cockcroft–Walton generator for example.

Quote: Originally posted by watson.fawkes

HV is dangerous. Posting random yammerings about isn't the most responsible thing in the world.

If you didn't notice, my "yammerings" were not the central point of my comment. I was just explaining why I cannot say for sure that the output voltage of a CFL step up transformer is 14,000V.

Don't assume that I don't experiment with high voltage because I don't know anything about it. On the contrary, I am too aware of the dangers and afraid to venture into that particular area of experimentation because of all the hazards involved. I'd rather be messing around with piranha solution and nitric acid instead.

watson.fawkes - 22-10-2011 at 07:44

Quote: Originally posted by White Yeti

I know what a voltage amplifier is, in fact I use one very often to boost voltage from certain homemade batteries.

This is exactly my point. You might know what a voltage amplifier is, but you don't have any idea what kind of voltage amplifier could take a 14 kV signal and amplify it to 100 kV. That's because they don't exist except perhaps in specialized research labs. Even radio transmitter tubes don't reach into this range.

"Voltage amplifier" means something specific, a device with a transfer function that converts an arbitrary input voltage within its operational domain to an output voltage that is an ideally-linear function of the input. A Marx generator is not a voltage amplifier. It's a pulse generator. A Cockcroft-Walton generator is not a voltage amplifier, but a voltage-multiplying rectifier. Neither of these circuits are voltage amplifiers. Just as with chemistry, terminology in electronics has specific meanings, and it behooves people to use these meanings and not invent their own.

Quote:

Don't assume that I don't experiment with high voltage because I don't know anything about it. On the contrary, I am too aware of the dangers and afraid to venture into that particular area of experimentation because of all the hazards involved.

Then please refrain from making baseless speculations about it. It's very much like posting uninformed shortcut syntheses for, say, organic peroxides, which is to say, irresponsible and dangerous to the uninformed who don't yet have functioning bullshit detectors.

unionised - 22-10-2011 at 08:55

"CFL transformer circuits can ramp the voltage up to about 14,000V."
Why?

White Yeti - 22-10-2011 at 10:02

Quote: Originally posted by unionised

"CFL transformer circuits can ramp the voltage up to about 14,000V."
Why?

A CFL is just a gas discharge tube that requires a high voltage to operate. 120V outlet power is not enough for a gas discharge tube to work, it has to be raised into the kilovolt range.

@watson.fawkes
I'm sorry I'm using incorrect terminology. I learned most electronic principles back in France and we call circuits like the Cockcroft–Walton generator "amplificateurs de tension".

Do you really think it's worth making such a fuss over terminology? You're wasting your time, find someone else to pick on.

watson.fawkes - 22-10-2011 at 11:40

Quote: Originally posted by White Yeti

I'm sorry I'm using incorrect terminology. I learned most electronic principles back in France and we call circuits like the Cockcroft–Walton generator "amplificateurs de tension".

Do you really think it's worth making such a fuss over terminology? You're wasting your time, find someone else to pick on.

I'm not picking on your terminology for its own sake. And I'm not picking on you for your diminishment, but in both these things I wish to protect the ignorant that might somehow believe you. Had you been posting analogous nonsense about high explosives, there would be many more here who might have corrected you, and with a goodly amount of flaming, to boot.

I had to look it up, but you're wrong about CFL operation, too. Starting voltages for typical consumer CFL are in the 300 - 500 V range, not even reaching even 1 kV, much less than the 14 kV you claimed.

White Yeti - 22-10-2011 at 12:43

You're right, I'm misinformed on the subject. I haven't done any research in years since I lost interest in high voltage. My apologies. I was just trying to contribute.
Just understand that I'm not trying to intentionally mislead anyone, I know it's a lose lose situation for everyone.

One area of high voltage that I am not misinformed on is the use of disposable camera flash circuits, I use them to increase the voltage of 2AA batteries to ~250V, the voltage required to power those small orange neon lamps, good stuff.

watson.fawkes - 22-10-2011 at 13:07

Quote: Originally posted by White Yeti

My apologies. I was just trying to contribute.
Just understand that I'm not trying to intentionally mislead anyone, I know it's a lose lose situation for everyone.

Thank you for your acknowledgement.

Quote:

One area of high voltage that I am not misinformed on is the use of disposable camera flash circuits, I use them to increase the voltage of 2AA batteries to ~250V, the voltage required to power those small orange neon lamps, good stuff.

That's right. That few-hundred-volt range is the typical breakdown voltage for low-pressure gas lamps. In each case, you have to create an ionization channel within the gas. It's not much of a surprise that creating that ionization channel is similar for flash lamps, fluorescent lamps, and neon glow lamps. They're all using a related physical principle. What's different is geometry, gas composition, and pressure. The little NE-2 neon two pin lamps can be started from 120V mains, though they'll be brighter with higher voltage as you were using. Their breakdown voltage is lower because the electrodes are only a couple of millimeters apart.

stygian - 22-10-2011 at 15:32

what sort of notation is 2AA? fwiw I dont have a problem with your use of the term voltage amplifier, as i understand it a voltage controlled nonlinear devices that produces proportional voltage variations wrt input, i also am glad somebody at least brought the point up of the semantic discrepancy, as they say, you learn a little every day

IrC - 22-10-2011 at 18:12

"what sort of notation is 2AA?"

Two "AA" batteries. You know, AAA, AA, C, D, and so on.

I would use another 2n3055 on a sink with a 10K Pot instead of a resistor to the ignition coil. Rail to top of Pot and collector. CT to base. Bottom of Pot to negative. Emitter is output to coil. A 100 uF on the base to negative, and a 1KuF to filter the regulator you just made with this circuit is a good idea also. Variable voltage to the coil and no resistor, unless you need some small value like an ohm or two in a few watt resistor to limit maximum current, could be added in series to the coil.

stygian - 22-10-2011 at 19:12

An plain dimmer switch plugged into the wall will drive an ignition coil fairly well so long as its left on the lowest setting, just dont run it for too long

edit: it needs a capacitor too

[Edited on 23-10-2011 by stygian]

unionised - 23-10-2011 at 06:51

I know you need a voltage spike to start most gas discharge tubes. However most of the CFL I hve seen are simply not big enough to contain a circuit that would stand 15KV without arcover. 1500 V perhaps, but not 15KV.

Also, it doesn't take that much voltage to start them, so why generate about 10 times the voltage you need.

bahramzoom - 17-5-2013 at 07:38

hi
i have a question and i must have the answer in a short time for my project.
how we can make a power supply like this :
110 V ,In ( 3phase )
110.000 V ,Out
and the size must be smaller, like a 20cm * 20cm ???
if u can help me it would be a great help for me
thanks.

Metacelsus - 17-5-2013 at 10:51

Do you want 3-phase, single-phase or DC out?
If you want 3-phase (which I assume), you want to build a step-up 3-phase transformer with a turn ratio of 1:1000. Making its base area less than 20cm by 20cm will be a challenge, especially if you are handling large primary currents.

Please, please, don't hurt yourself. The highest voltage I've worked with was 50 kV (at around 10 mA), and that was genuinely nerve-wracking. I hope this is not your first HV project.

[Edited on 17-5-2013 by Cheddite Cheese]

bahramzoom - 18-5-2013 at 09:06

thanks about your comment, but i have to do it and some of details were wrong. i need this details :
Input : 115v ac , 3 phase , 400 hz ( or 60hz )
Output : 11kv DC , 18kw power ( watt ) , 1.5 Amper
what`s your idea ?

12AX7 - 18-5-2013 at 09:27

Sounds like an antique radiotransmitter power supply.

Metacelsus - 18-5-2013 at 11:09

My idea is to step up the AC with a transformer and rectify it. You would just need a smaller turn ratio. Higher frequency is better here; it reduces the size of the transformer you need.

An 18 kVA one would definitely be larger than 20cm by 20cm base area, even at 400 Hz.

Alternatively, you could use a Cockroft-Walton multiplier, but I am not familiar with any that run off of 3-phase, and handling 18 kW might prove difficult.

Knowing the kind of load you plan to use would be helpful.

IrC - 18-5-2013 at 15:41

bahramzoom, being unclear in your specific needs and incorrect math leads one to wonder if you even know what you are talking about. You will never get 18.5 KW out of any normal service. That and the need for 3 phase means industrial power service. For nearly 20 KW of continuous industrial power service you are going to have a 480 volt panel at your end with three 1,200 ampere breakers, one for each leg. The power company is not going to set you up with a service able to supply 16.5 KW at either 110 or 220 volts (or 117/~240). Just FYI but 480 volt breaker panels like to explode so you might want to wear a protective suit while working on it. In my career I've seen them explode twice, both times lives lost. Just thought I would forewarn you since you are not going to get a power service this radical at 110 or 220. In other words you will be working with 480 volt power so get used to it.

Then coming in with the shifting 60 or 400 HZ requirements adds to the confusion. Stating 18 KW, 1.5 amps, 11 KV, merely indicates you cannot multiply EI to get the correct 16.5 KW. Anyone versed enough in HVAC to be responsible and safe at these power levels would never have made several of the statements you posted. This adds further fuel to the 'you don't know what you are talking about' fire. OK, so does the 20cm by 20cm base area request for this power level. Go outside and look up at the transformer feeding your house. Depending upon age and your grid this will likely be a 5KVA or max 10 KVA pole pig with 14,400 60 HZ primary. From this and the need for at least 50 percent de-rating you can get an idea of the size of transformer for your approaching 20 kilowatt power level. For sure "20cm by 20cm base area" is out the window. Especially if you include 3 phase rectification and any needed filtering with specs able to withstand this much power at these voltages.

If you had a clue you would know you are not going to get this power at any other frequency than 60 HZ, or 50 if on another continent. Damn sure not at 400 HZ. In fact at 400 HZ and 11KV/1.5 ampere fed by 3 phase you will need a JT8D jet engine, monster 3 phase alternator (with gear reduction since your turbine will be around 100,000 RPM), a 3 phase step-up transformer also huge, and a 3 phase bridge rectifier able to handle these power levels, along with whatever filtering you may need. With the lack of knowledge and experience demonstrated by your posts no way would I trust you to safely work anywhere near my neighborhood with whatever it is you are building. In fact to work at this level safely, you should have already possessed enough knowledge none of your questions needed asking. I am not trying (too hard) to be rude but are you even safe handling a potato gun?

Why don't you state in clear terms exactly what it is you are trying to build or do?

bahramzoom - 19-5-2013 at 02:06

in fact i'm the student in Thailand and its my project to improve the circuit with that details.i have to finish it before 2month. the proffossor diden`t tell me about the exact details what are they trying to do but i think they wanna make a
metal detector .

watson.fawkes - 19-5-2013 at 05:40

Quote: Originally posted by IrC

If you had a clue you would know you are not going to get this power at any other frequency than 60 HZ, or 50 if on another continent. Damn sure not at 400 HZ. In fact at 400 HZ and 11KV/1.5 ampere fed by 3 phase you will need a JT8D jet engine

That may be exactly what's going on here. 400 Hz is used for power distribution on aircraft. 400 Hz is mostly used in military applications, though not entirely. My surmise, lacking other information, is that this 18 kW DC HV supply is part of some weapon system.

Metacelsus - 19-5-2013 at 07:05

WHY do you need that kind of power (and voltage) to make a metal detector?

IrC - 19-5-2013 at 17:49

Quote: Originally posted by Cheddite Cheese

WHY do you need that kind of power (and voltage) to make a metal detector?

Asteroid mining?

bahramzoom - 24-5-2013 at 02:17

is that important what is that for ? if you can`t help me just tell it.
thanks about your replys in this 'TECHNOLOGY' forum .

phlogiston - 24-5-2013 at 03:21

Short circuit the power supply with the material being tested.
KABOOM = metal