Sources for high voltage power supplies?

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

I apologize - I was unclear in my OP.

There will be exactly one of these made :) It's for research. Something to do with applying various voltages across a channel containing a fluid made up of "magic particles" (their words, not mine). Space and weight are completely non-issues. As for cost - we don't have a set price that we're looking to pay or anything - but saving money would be nice, naturally. Right now my plan is to get one of those Bertan supplies if I can't find anything cheaper. My bosses will probabaly be a bit miffed - but oh well, I'm sure they'll get over it.

Thanks, and sorry if I came off as rude. I would never want to be rude to the author of the book that spends more time on my desk than any other book.

-M. Noone

"Chris" wrote in news:1111420964.293831.31780 @g14g2000cwa.googlegroups.com:

one

simple

supply

I have suggested that everything be fully insulated - but it remains to be seen whether or not they take my advice. Certainly the circuits I'm building for this beast will all be fully protected like you have advised.

guy

slacking

can

Oh - don't worry about my job security :) I'd take a lot to get fired - and even if I did it wouldn't be *that* big of a deal... Mostly I'll just get chewed out if they think I'm being too slow.

with

If

email

I'll try to do some substantial research about HV. I'm an EE undergrad student and we haven't even mentioned HV design yet. Everything we've covered so far is about small signals.

take

I just e-mailed them again to see if they had decided on anything - I'll get back to you on that.

They want a max output of 20ma on each of the 10 outputs - so .2A total max output, though in reality it should be quite a good deal less than that.

with

I don't think there will be any ripple - but the load will be changing, if that will be a problem

Nope.

I'm not quite sure what you mean here - what would be arcing?

what

What exactly do you mean by operational control? As far as I know - initially they'll need to set the voltage - and after that they'll just need to turn it on and off.

need

I'll have a look through it. Thanks for the link.

reasons

Thanks,

-Michael

to

I'm

I'm afraid I don't like what I'm hearing here. As a member of a project team with assigned responsibility for the electronics, you are in charge of making sure the electrons and holes stay where they they belong. That's true whether you build or buy the supply. The supply itself can be perfectly safe, but if it's improperly applied in a project where you're assigned responsibility for that portion, you're responsible, at least from an ethical standpoint. Also from an employer's standpoint. If you were doing research in an industrial ceramics lab, as the project EE, and someone was hurt because of an omission of yours, you'd get fired. And rightly so. It shouldn't cost very much to make it safe.

The other thing is, your reverse mousetrap shows you're taking initiative, are willing to work hard to make the project happen, and as an extra added bonus, may give you a little more time to learn what you need to know. You don't think every EE who's assigned a project has all the knowledge they need to complete it before they start? Ho ho, nyuk nyuk. And they want you to start working productively on day 1, whether you know everything you need or not. In the real world, it's common to use the "swiss cheese method", and work your projects by doing the parts you know how to do while scrambling to get up to speed on the rest.

undergrad

But, as I mentioned above, there's enough practical advice that can be given about dealing with HV to take an experienced EE or engineering tech a few hours to teach. Not substantial, but practical and necessary. You can't get it in books or on the internets (at least that I'm aware of), and it's really helpful to have someone look over your shoulder and check your work, even if you could read what you need to know. You've indicated that you're doing this at a college/university with an EE program. Most have a crusty old tech somewhere in the back (you'll frequently find him in the toolroom or repair depot) who would be delighted to be freed of his imprisonment to have a chance to teach some real world knowledge. As I've said before, techs are usually much freer with advice if you offer them a six of their favorite libation or some other similar inducement. Also check out resources in the computer department, and any other likely suspects.

microswitch

I'll

The point is that one practical experiment is sometimes worth more than all the collective wisdom of the project group. Get a good power supply and help them find out what they need.

and

total

than

Again, try it and you may, I say. Get a power supply, plug it in, and find out.

changing,

To specify a DC power supply, you use many parameters. Some of them are:

• Voltage Range (min/max)

• Current Range (max)

• Current limit/foldback/shutdown

• Voltage control or dual voltage/current control

• Line regulation

• Load regulation

• Ripple (Output AC voltage superimposed on the DC output, over line and load range)

The last three are critical, because you're looking for a cheapie solution, and should be hoping (I would) you can get away with an unregulated supply (possibly controlled by Variac). You might even be able to just cannibalize an old tube boat anchor and steal the filament transformer, series filter choke or resistors and caps, and be done with it for a miraculous low price. However, that isn't going to happen if their application can't have more than 20mV p.p. of AC ripple. That may also mean you require a linear power supply rather than a HV switcher. Good to know.

need a

just

Imagine that you had a "super operational amplifier", that could be programmed by feedback and/or a low voltage input, whose output went from, say, 0 to 1000V with a current capability of 0 to 100 mA and a power bandwidth in the audio range. That's an "operational" power supply, a gift from the gods for research labs that are doing HV stuff. Some are unidirectional (they can only source current), and some are bidirectional (source or sink). Some will also be bipolar (with output voltage range, say, from +400V to -400V, sourcing and sinking current with positive or negative output). An operational power supply would be ideal to rent, because you could simulate various amounts of ripple and voltage sag to see if an unregulated or poorly regulated supply would do the job, allowing you to home brew something quick & dirty and saving money.

Well, Michael. This business of inserting replies in the middle of copies of another post may work well in Outlook for email (where you can use colors to distinguish replies) but it doesn't work well in newsgroups. Also, it leads to time-consuming editing which might distort meaning. Try to collect all your answers and post below the copy of the prior response, please.

I'm serious about your finding somebody knowledgeable to stand in front of you and give a few pointers about HV, and check your ideas and work. Be safe first.

Luck is the residue of hard work. Good luck, Mike. Chris