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Voltage multiplier and neon transformer.

Posted: Wed Sep 18, 2013 7:27 pm
by Martin Shahi
Hi guys so I have had a thought and I would just like to know if it would work.
So if I had found a neon transformer that puts out 9000V at 60 milliamps, and then used a voltage multiplier circuit like this: http://en.wikipedia.org/wiki/File:Volta ... iagram.PNG

Would this provide the necessary current and voltage to run a full fusor?

If this wouldn't work then I'm thinking of winding my own transformer and then using a circuit such as the one above. If anyone has any experience winding transformers then I would be very grateful for any advice.

Thanks

Re: Voltage multiplier and neon transformer.

Posted: Wed Sep 18, 2013 8:29 pm
by Rich Feldman
Hi Martin.

Winding transformers can be a rewarding and educational experience, and I've done it more than once. But think you should start with something easier and simpler than a NST.

The answers to your questions are all in the FAQs. Yes, there are lots of FAQs, even just under high voltage power. But not too many to read in a couple hours, even without using the search feature to prune the list.

For after your homework, here are some quiz questions about just the NST, with no voltage multiplier.
If you don't know an answer, skip it and try the next question.

0. With an ordinary power transformer in good working order, what external connection are required
to make the actual output voltage and current BOTH match the nameplate values?

1. NST ratings are given differently than the ratings of ordinary power transformers.
What's the difference between "puts out 9000V at 60 milliamps" and "Nameplate voltage is 9000; nameplate current is 60" ?

2. When there is no current, what's the voltage between each HV output and the center tap (internally tied to transformer case)?
Is that RMS voltage or peak voltage?

3. What's the current in a wire connected between the two HV outputs? ( A condition similar to a lit neon sign ).

4. What would be the RMS current in a 150,000 ohm resistor connected between the two HV outputs?

I will soon be making those measurement on a similar transformer and posting the result.
Richard Hull posted work along those lines many, many years ago.

Re: Voltage multiplier and neon transformer.

Posted: Wed Sep 18, 2013 8:58 pm
by Richard Hull
The neon Transformer paper is in the files forum

viewtopic.php?f=19&t=7945

Richard Hull

Re: Voltage multiplier and neon transformer.

Posted: Thu Sep 19, 2013 3:47 pm
by Martin Shahi
Richard Hull wrote:The neon Transformer paper is in the files forum



Richard Hull
Thank you very much Richard, I hope that I understood it and I think it helped a good deal.

Re: Voltage multiplier and neon transformer.

Posted: Thu Sep 19, 2013 4:17 pm
by Martin Shahi
Rich Feldman wrote:
0. With an ordinary power transformer in good working order, what external connection are required
to make the actual output voltage and current BOTH match the nameplate values?

Not really sure what you mean by this. I think a transformer needs a mains input, live and neutral, and then on it's output it goes to whatever component requires the electrical energy to operate. Sorry if I misunderstood the question.

1. NST ratings are given differently than the ratings of ordinary power transformers.
What's the difference between "puts out 9000V at 60 milliamps" and "Nameplate voltage is 9000; nameplate current is 60" ?

I think the difference is that the nameplate is the maximum which it is capable of, not what it really puts out due resistance. Not sure though.

2. When there is no current, what's the voltage between each HV output and the center tap (internally tied to transformer case)?
Is that RMS voltage or peak voltage?

Is the voltage of this particular NST 9000v and is this peak voltage?

3. What's the current in a wire connected between the two HV outputs? ( A condition similar to a lit neon sign ).

It would be alternating in direction. Not sure if this is the answer you wanted

4. What would be the RMS current in a 150,000 ohm resistor connected between the two HV outputs?
I don't know this unfortunately. I tried looking up the formulas on wikipedia but couldn't make heads or tails of it.

I'm sorry if I'm woefully ignorant on the subject, but everything I know I have tried to teach myself as we do nothing like this in school yet. I hope we will in physics sometime so that I can rid myself of the ignorance i have.
Also having read Richard's document and the "two thirds rule" I assume that the NST I have in mind wouldn't be able to power a fusor as the actual output of it would be around 6000v and 20mA, and if I used a voltage multiplier circuit on this then I would only get 5mA which isn't enough. Am I correct in this?
Thanks

Re: Voltage multiplier and neon transformer.

Posted: Thu Sep 19, 2013 5:55 pm
by Richard Hull
The general answer to the question of a neon sign transformer doing fusion is..... NO! (This relates more to the skills and knowledge base of the average newbie....lack thereof.... than to the possibility of doing fusion with the sign transformer.)

Not impossible, however. A very skilled, electronics capable, pair of hands might do it. The effort would demand that a very sensitive neutron detector is at hand. (never a newbie specialty) Unfortunately, success with a neon sign transfomrer would be a Pyrrhic victory, at best. You couldn't do much work with the resultant fusor except claim you had done marginally detectable fusion.

Richard Hull

Re: Voltage multiplier and neon transformer.

Posted: Thu Sep 19, 2013 7:14 pm
by Martin Shahi
Ok thanks Richard

Re: Voltage multiplier and neon transformer.

Posted: Fri Sep 20, 2013 5:02 pm
by Rich Feldman
Hi Martin.

Thank you for taking a shot at my quiz questions. It tells us where you stand today in electrical knowledge.
You deserve a point by point response, which I'll send privately.

Respectfully,
Rich Feldman

p.s. Please don't hold your breath until then. :-)

Re: Voltage multiplier and neon transformer.

Posted: Mon Jan 26, 2015 6:41 pm
by Charles Vorbach
Rich Feldman wrote:
0. With an ordinary power transformer in good working order, what external connection are required
to make the actual output voltage and current BOTH match the nameplate values?

1. NST ratings are given differently than the ratings of ordinary power transformers.
What's the difference between "puts out 9000V at 60 milliamps" and "Nameplate voltage is 9000; nameplate current is 60" ?

2. When there is no current, what's the voltage between each HV output and the center tap (internally tied to transformer case)?
Is that RMS voltage or peak voltage?

3. What's the current in a wire connected between the two HV outputs? ( A condition similar to a lit neon sign ).

4. What would be the RMS current in a 150,000 ohm resistor connected between the two HV outputs?
Great questions! This sort of thing could be helpful in the FAQs.

0. An ordinary power transformer will give nameplate voltage and current (and maybe a little more) between the ends of its HV winding.
1. Voltage ratings are for open loop and current ratings are for shorted. Based on Richard's investigation, you can only hope for 2/3 current and 2/3 voltage at the same time.
2. One half the nameplate voltage, RMS.
3. Nameplate current.
4. On Martin's transformer, 45 milliamps maybe?

Re: Voltage multiplier and neon transformer.

Posted: Mon Jan 26, 2015 8:09 pm
by Andrew Haynes
Hi Martin you could get 30kv and 15ma from a 15kv 30ma neon but you have to increase the resisance to follow ohms law, and stop the magnetic shunt from kicking in, I have mangered to get 60kv at 0.5ma from the bwlow nst

Prettyuch put a 40kv 800pf cap in series with a 15kv 10ma nst and you will get 15kv 5ma