MOTs ???

[daniele]

Like pole pigs, they are not current limited.
So every current limiting issue is not being discussed.

I have questions about the possibility of using a number of mots to build a larger unit... (they are cheap!)
I was thinking about building an oil immersed unit.
I remeber about problems (phasing? transformer core hot?)
So I need a good refresh or internet source for meditation, If someone can help.

tnx all again
ciao
Daniele

[Richard Hull]

Microwave oven transformers are not the best trasformers, as they rarely hit 2000 volts. Series stringing them runs a risk of insulation failure, hot core arc over, etc.

If you must use one I suggest a voltage multiplier circuit on a single unit to obtain the desired voltage. A nice high wattage power resistor of about 60k-100k ohms in series with the transformer and the multiplier will limit the output of the transformer and protect the multiplier nicely while dropping the voltage if you get into a near shorted condition.

To series a large number of them would require a plastic tank where they could be separated and insulated core to core. The whole mess would then need to be under oil. There is still no guarantee that the insulation might not fail secondary to primary under high current spike conditions.

Richard Hull

[daniele]

Richard Hull wrote:
>
> To series a large number of them would require a plastic tank where they could be separated and insulated core to core. The whole mess would then need to be under oil. There is still no guarantee that the insulation might not fail secondary to primary under high current spike conditions.
>

Please let me know what do you think about this kind of setup ...
Tnx

Daniele

[Mike Veldman]

This looks like a lot of trouble to go through to raise the voltage. You will spend a lot of time looking for matched ovens to rob the four transformers used as isolation, plus you'll need to correct the error in the schematic grounding the isolated loop. Having played this game way back in my youth trying to build HV supplies with surplus plate and TV transformers, the series transformers will also have to be current matched. A multiplier off of a 60ma NST might be easier, (although I've not tried it on a fusor) if nothing else lighter.
mike

[Richard Hull]

Well done on the circuitry! This would of course work fine, but again your voltage is always limited. even with 8 stacks you are looking at no more than 6-8kv on each side of ground. Assuming the output of your supply has to have ground as a reference, (most do), you might develop as much as 10kv dc from an 8 stack. The power level would be superb, however, at that voltage.

Some folks can get MOTs for $1.00-$2.00 each in quantity at hamfests. I have seen them in the $1.00-$5.00 range at all hamfests. I picked a couple out of a freebie box at one fest a few months back.

Matching the MOTs is not a big issue unless you want to parallel some. Serial connected units can have widely different characteristics.

for more good info on transofrmers including MOTs check out

http://www.kronjaeger.com

This is his new page. His old page is no longer active and the nice archived stuff is down, maybe for good. I assum he graduated or got shoved off of his university's site and is now paying for his own site. Jochen's site was one of the best hands on HV sites on the web.

Richard Hull

Richard Hull

[daniele]

tnx guys

(The circuitry is not by me, check out the url in the pic)

Daniele

[guest]

I looked in on the altair website about 2 years ago.
The site has added a great deal in hv projects.
My favorites are the theta machine and his telsa setups
.
Very classy site complete with screaming sculls for death warnings.

Larry Leins
Physics Teacher