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First Thread : A challenge and an opportunity for all of you here!

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sashua

Fri Jul 09 2010, 03:10PM

Registered Member #2984 Joined: Fri Jul 09 2010, 02:55PM
Location:
Posts: 4

I am looking to either find or have someone make a modulated High Voltage power supply for me but my needs are pretty specific and the only options I have been able to locate on the market are insanely expensive and still don't really fit my requirements.

I would like to ask the group here for a referral to someone who can make this or receive an offer from one of you directly to do so. I can pay fairly and the potential for additional units after the first one is strong. This is for an audio device, the details of which I can share with the potential manufacturer immediately and with the group here after completion.

Here are the parameters:

A. Bunt to the infield: Bare minimum might be +/-3kV output capability at 10mA non-floating (or equivalently, non-isolated -- It just means the negative output terminal might have to be grounded or have limited ability to be biased to high voltage). Capability of 20Hz to 3kHz audio bandwidth

B. Home-run: +/-5kV or more at 50mA or more with floating outputs to 20kV so we could connect it in series with a DC supply. The AC part must be the audio frequency band (20Hz to 20kHz).

C. Grand-slam: A "modulator" that combines both DC capability up to 20kV DC with +/-5kV AC capability, all at 50mA or more. The AC part must be the audio frequency band (20Hz to 20kHz).

Obviously the Grand Slam option would be our most perfect solution.

I can be contacted during the week at my office (631) 342-0043 (x101) or by e-mail at **link**

Fingers crossed!
Russ

Pinky's Brain

Fri Jul 09 2010, 03:36PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
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Posts: 837

Not that I'm in a position to help ... but I'm curious, what kind of load would it be driving (inductive/capacitive/resistive) and how much THD is acceptable?

Patrick

Fri Jul 09 2010, 08:23PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

when you say "modulated" what do you mean?

i might be willing to do this, but my first instinct is to use a ferrite txfmr @ 40khz that can be audio modulated from 0-10 volts input or so, to establish the 20hz-20khz , but i need to know more about what you want for output. obviously i cant AM modulate the ferrite at 20Hz, but i can approximate it given your willingness to accept THD. when would you need the first one made by? maybe i can figure something better out later.

quicksilver

Sat Jul 10 2010, 07:12PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

I don't think he'd plug his own site .... so I'll do it for him.
Eastern Volt Research Kits are nice. The fellow is a contributor and certainly within your means. You only need to solder: that's no problem; right?
Check out his web page by Googling the name and look for his class D/E SSTC driver.

7/11
(yep, I goofed -= edit=- )

IF however you are looking to get more specific; you can hunt surplus sales of nebraska. They have some wonderful surplus PSU's from Los Alamos and quite a few new items. It's a friendly customer-service place in my experience.

Pinky's Brain

Sat Jul 10 2010, 09:21PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
Location:
Posts: 837

Don't you mean the Eastern voltage class D/E SSTC drivers? The flyback driver can't be modulated AFAICS.

Sulaiman

Sun Jul 11 2010, 07:12AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

For the ac part;
do you need +/- 5 kV at 20 Hz AND 20 kHz ?
-an amplifier that provides +/- 5 kV at 20 Hz falling (1/f) to +/- 5 V at 20 kHz is much cheaper,
..(assuming a capacitive load)

for the dc part;
20 kV at 50 mA is 1 kW dc ... something is going to get really hot or die!
Plus I can't imagine the legal liabilities for such a power supply.

The spec. on your requirements seems very loose,
a little consideration could save a lot of time/money.

Your first post, although interesting, breaks so many rules of this forum.

Hazmatt_(The Underdog)

Sun Jul 11 2010, 06:15PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Since you're dealing with audio ranges it's not such a big problem, Get yourself a Modulator Transformer for an old radio station. I had one for a little while but I tossed it because it was becoming a pain to store. They weigh about 120 lbs and are designed to modulate the plate voltage of AM transmitters.
You will need a fairly large amp to drive the modulator transformer though, likely a pair of 833 tubes (I think that was what was marked on the one I had).
Anyways, that should do it, or you could make your own modulator transformer with an audio core from someone.

Patrick

Mon Jul 12 2010, 05:38AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

yeah, as sulaiman said this thread does seem to violate posting rules. i wonder if it will be scrubbed soon?

sashua

Mon Jul 12 2010, 02:36PM

Registered Member #2984 Joined: Fri Jul 09 2010, 02:55PM
Location:
Posts: 4

Hi everyone, OP here.

If this is considered a commercial endeavor and I am violating any rule then I sincerely apologize.

Kindly let me re-state my position and remove the offer for assistance by remuneration.

I am offering only my gratitude and requesting help with my dilemma. My partner in this project is capable of making the power supply (assuming it is within reason to do so) and we would like to humbly request some assistance with the design or some advice on how to go about sourcing it.

You may contact me privately if you wish or simply post here for an open discussion.

I will now ask Dr. Colin Joye to step into this conversation and answer all of your questions as I only have a rudimentary understanding of it.

I do TRULY appreciate all the help and advice here and I am so glad that I found a forum which is so focused on exactly what we see as one of our our biggest challenges currently.

Colin should join in sometime this evening and with a little luck and the kind help of all the great intelligencia present here, I am sure a solution will present itself.

Regards,
Russ

cdanjo

Mon Jul 12 2010, 10:31PM

Registered Member #2995 Joined: Mon Jul 12 2010, 10:12PM
Location:
Posts: 4

Okay, here I am... Wow, I should have joined this forum long ago! I've been playing with high voltage since I could ride a bike (hey now, I'm not THAT slow a learner!).

Anyway, Russ and I are planning to drive a plasma-type load, like an ionic thruster (no, they're NOT anti-gravity, just the Biefield-Brown electrohydrodynamic effect). Yeah, maybe 50mA is overkill for average, but might be needed for peaks, but I don't know how much it will require. I have a 0.5mA 35kv supply and it can't even make a tiny lifter lift!

THD? For now, I'd probably be happy with a few % at the low end and hopefully 1% or under at 1kHz. Ultimately, if the concept works, we'd want it below that in a fairly compact package. I've considered tubes, IGBTs, step-up transformers, but don't have the time to build things that don't work. Hopefully one of you has built high voltage modulators before. A 40kHz switching frequency is pretty low -- If you've got an idea, I've switched chunky FETs up to 15MHz before. I'd like to be about 5x Nyquist or more (200kHz or more).

By "modulate" I mean have a ~15kvdc supply and shake it around with maybe +/-5kv AC; in other words, be able to control the voltage from 10 to 20kv using a control line with 20kHz bandwidth.

-Colin

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