Sources for high voltage power supplies?

As long as the subject is on the table, I can mention the names of a half-dozen companies that make small low-cost modules with output voltages ranging from 0.5kV to 10kV, some with isolated outputs. These are all small unregulated modules well suited for powering other high-voltage circuitry, discrete opamps, etc., etc. If a precise voltage is wanted, you add a simple feedback loop to control the input voltage. I have four or five favorite circuits for this purpose, and over the years have found this to be a more effective way to go than making custom HV supplies. This is true even if one has to add output filters, current sensing, fast shutoff, etc.

One of the names is EMCO,

I can also give you the names of a number of high-power high- voltage supply companies, but it'll have to wait until I get back from vacation. One name is (was) Bertan, now part of Spellman, another name.

They make power supplies from 0.2W to 120kW, and 0.25 to 360kV.

--
 Thanks,
    - Win

I would check again. The PNC series goes up to 300.000 Volts = 300 kV. That should be enough. Regards Manrkus Mandl

I read in sci.electronics.design that Michael Noone wrote (in ) about 'Sources for high voltage power supplies?', on Sun, 20 Mar 2005:

Not for voltages over about 300 V, because you need serious HV components, which aren't made in high volumes, for higher voltages.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in sci.electronics.design that Michael Noone wrote (in ) about 'Sources for high voltage power supplies?', on Sun, 20 Mar 2005:

Well, think about the one at the top of the chain. The whole secondary circuit is at +800 V or whatever but the transformer core is grounded, or should be.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Surely one could avoid this problem by not connecting one end of the secondaries to earth?

Regards, Alan

--
Alan R. Turner | Live never to be ashamed of anything you do or say.
To reply by email, remove Mr Blobby.

Alan Turner wrote in news: snipped-for-privacy@mrblobbybiccard.com:

Hmm - though it would be fairly practical - I expect my superiors would shoot that idea down rather quickly. Though I must admit it'd be damn fun to make a huge block of batteries... Though charging would be a pain.

-M. Noone

I read in sci.electronics.design that Alan Turner wrote (in ) about 'Sources for high voltage power supplies?', on Mon, 21 Mar 2005:

Then the whole HV shebang is floating, and can build up charge to a somewhat unlimited level. That's even more dangerous.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Winfield Hill wrote in news: snipped-for-privacy@drn.newsguy.com:

I found this company before I posted my question through Google - but as far as I can tell - their most powerful power supply is 15W, which puts it well under what I need.

Yup - I also looked at Bertan power supplies - but they seem to be very expensive (I believe in the >$1K range, according to what their power supplies are fetching on Ebay), though I also haven't heard back from their sales rep just yet, so that remains to be seen.

Thanks,

M. Noone

Well - if it's cheaper and it does the job - what have they got to whinge about? Sometimes a pragmatic approach is the best :)

I'd arrange a small charger board for each battery. Supplying power to the charger board would drive a relay which removes the battery from the big series pack and connects it to the charger.

When you pack up in the evening, you just flick a switch which enables the charger circuits. The whole thing could go on a trolley.

I suppose such a supply would be rather dangerous. It would probably arc quite nastily if you were to accidentally short it out for an instant. Some kind of switch capable of breaking fault current may be in order. Maybe a fuse?

Regards, Alan

--
Alan R. Turner | Live never to be ashamed of anything you do or say.
To reply by email, remove Mr Blobby.

Thanks for your reply. I suppose one would ground the middle of the set :-)

Regards, Alan

--
Alan R. Turner | Live never to be ashamed of anything you do or say.
To reply by email, remove Mr Blobby.

Oh, I thought you said, "I can't find ANY high dc voltage power supplies." I guess we were wasting our time.

Maybe if you want more help you should tell us what this is for, how many you'll be making, what country you're posting from, and what your space, weight and cost budgets are. You wouldn't want us to keep giving you all these useless suggestions, would you?

--
 Thanks,
    - Win

I read in sci.electronics.design that Alan Turner wrote (in ) about 'Sources for high voltage power supplies?', on Mon, 21 Mar 2005:

The OP was asking about a +/- 800 V supply, so the mid-point would indeed be grounded.

--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

sure

(I

150

as

puts

very

Hi. You've got yourself a passel of problems here. Let's take 'em one at a time.

1) SAFETY. When you're dealing with high voltage DC, you're talking about potentially killing someone, either yourself, one of the researchers, or an operator or someone else who wanders in and touches the wrong thing. Before anything else, when you're developing a high voltage fixture for R&D, you have to build a reverse mousetrap to prevent someone who's smart but distracted from accidentally electrocuting themselves. For something small, this could be as simple as a small Lexan box with a lexan door with magnetic latch and microswitch safety. The idea is to immediately neuter the power supply in the event someone could conceivably get buzzed off. Not all that difficult if you use your head.

The thing is, you should have done this first, and now you're under pressure to produce something. Well, you have to DO THIS FIRST. If you're out of time, do it first. If they've promised to let you go if you don't give them something immediately, do this first and let them fire you. There are more important things than a job, and the next guy will have a head start. And besides, it shows you're not just slacking off, and are willing to work toward a solution. That may be in question at this point, which is just about the worst situation you can be in.

2) HV KNOWLEDGE. This part is a little tricky. Apparently you don't have much experience here. That can be a literally fatal problem. It might be better to ask around, and talk to somebody who's familiar with HV. If no one's available, find an old EE or engineering tech who's familiar with the art, and have him teach you. It won't take long. If you're in a city of any size, you'll probably be able to find someone without too much problem. If you need it right away and can't find anyone, call one of the temp services and ask for the services of someone who's familiar with HV fixturing. He can teach you a lot in a couple of hours. If you happen to be in the Chicago area, use my email

-- I'll be happy to kibbitz (for a reasonable fee ;-)

3) PEOPLE PROBLEM. I think Don Lancaster once said something like, "For any job there's the technical problem and the people problem." Believe it or not, the people problem is every bit as important as the technical issues most of the time, and in this case, it's become the predominant factor. You're dealing with researchers here. They've admitted that the electronics end of the project is outside of their sphere of competence -- that's what you're there for. Also, their job is to research. If they knew exactly what to do, they wouldn't need you. An ever-changing power supply requirement isn't a fatal problem here. Being in a "chicken-and-egg" hangup is, and you're the one that's going to look bad.

OK, some practical advice. You've got to walk in with a plan, and take charge here. Your "extemporizing" time has pretty much evaporated, I guess. Here's what you might do:

• Stop at the local hardware store. Buy some thick plexiglas, acryllic cement, and aluminum angle stock, along with a selection of

6-32 and 8-32 screws, nuts and lock washers. Start building your safety enclosure immediately. Farm out some of the machining if you can -- it will save time.

• Once that's done, your first job is to give these guys something to work with so they can find some answers to give you. Start out by renting a HV DC power supply for a week -- that should cost less than 0 USD plus shipping. Spec a good one with an emergency shutdown circuit, and be sure to wire your reverse mousetrap safety microswitch into the circuit before you let 'em at it. Let them play, and be creative and curious. Watch what they're doing. Help to keep them moving. Ask good questions:

- Do you have an idea of voltage requirements yet?

- How about maximum current? (If this is an electrostatic application, you probably won't need a tenth of the current you're talking about. But you'll never know until you plug something in and check it out. It's your job to measure things.)

- How much ripple voltage(many electrostatic applications go nuts with a superimposed AC ripple)?

- Do they need soft start (voltage ramps up to value)?

- How about arcing on shutdown?

- Do they need operational control over the power supply? If so, what bandwidth? Or can you "make do" with a couple of relays if you need a bidirectional supply?

Once you get good answers, you can start to look at whether a "home brew" job will be good enough, or if not, how much you're going to need to spend on a store-bought power supply.

By the way, working on the assumption that this is an electrostatic application, I'd like to second Mr. Hill's suggestion to look at the Spellman HV catalog, if for no other reason than to learn about what questions to ask. They're good folk to know if you have HV problems. One of their technical resource articles in particular may be of some interest:

High Voltage Power Supplies for Electrostatic Applications

This will help you in the process of specifying the power supply, and lists some of the "gotchas" you'll have to watch for. Don't overlook the possibility of just giving them a call.They do have apps engineers to help.

Most importantly, work on the relationships here, and give them reasons to have confidence in you. You're a force multiplier, and have been put on the job to make them more effective. If you look at it that way, you will have more success, and won't be the "people problem". You have no idea what a good job you have here. Take advantage of it. I've been where you are now, before I learned how not to do it. It isn't fun, you don't look good, and there is a way out.

Good luck Chris

Do you have any idea what these guys are trying to accomplish? A number of years ago, I worked with a variety of HV supplies, from a scanning electron microscope to a variety of ion guns to an X-ray source.

What kind of experiments are these people doing? Do they have a vacuum chamber? An electrolytic vessel? A heater of some kind? A laser? Do their experiments have any parameters?

Knowing what they're trying to drive will considerably narrow the field of what you might want to try. (maybe a capacitive sensor to read out density in a fluidized bed? ;-) )

Good Luck! Rich

And some diodes - capacitor/choke are optional, as you characterize the MMs for ripple amplitude.

Just put the transformer on the variac, rectify it, and optionally filter it.

That's about the cheapest adjustable HV supply I can think of at the moment.

Cheers! Rich

They are academics. They essentially have the opposite of a clue when it comes to real-world stuff.

I still say Michael should take a stand: "Here is the power supply that meets your specification - I'm sorry that it costs thirty thousand dollars, but this is what it takes to meet your impossible specifications. I _am_ the engineer here after all, and you obviously have no idea what you need, which is why you hired me, no? This is the one you need. Use it, pay me, and we can get on with our experiments."

Good Luck! Rich

This is another question that's nagging at me - they're applying a voltage to a stream of magic molecules, right? Do they have any idea how their stream is expected to dissipate hundreds of watts?

Thanks, Rich

sure yet

150 or

of a

These

input

and

than

output

but as

puts it

voltage

their

Hi, Rich. That's why I'd personally guess it's an electrostatic application. It seems they're trying to apply a charge/field to these molecules to get them to do something "magic", rather than pumping current through them.

The best path for the OP might be, "Fire...Ready...Aim". The people who are running the project have to plug something in and make some measurements to find out what they need. Actually making smoke is a very good way to get the angels off the head of the pin. Besides, in a practical, job-security sense, it will give the project leaders something to do besides complaining to the OP about turning the project into a dead parrot.

By the way, I saw that post of yours upstream --

"Knowing what they're trying to drive will considerably narrow the field of what you might want to try. (maybe a capacitive sensor to read out density in a fluidized bed? ;-) ) "

I resemble that remark! ;-D

Chris

Rich Grise wrote in news: snipped-for-privacy@example.net:

That's actually a great question, come to think of it. They told me to allow 20ma per output (and there are 10 outputs all connected to the same advice) - though in reality I expect only one or two outputs will be on at a given time. But still - that's quite a lot of power. I just e-mailed one of the researchers - I'll let you know what he says.

-M. Noone