Why pulsed power needs 500 ma

This forum is for specialized infomation important to the construction and safe operation of the high voltage electrical supplies and related circuitry needed for fusor operation.
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Why pulsed power needs 500 ma

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WARNING********
The whole fusor will have to be housed in a faraday cage. This includes power supply also. About the last
thing this group needs is to have a member destroy
a power grid by emi overload. Law suits galore! Not to mention the possible damages to properties and loss of life. This means battery powered fusor supplies also. A fusion test shot will kill tv reception, burn up comos ic's, kill anything with intelligence in it, cars ,microwave ovens, wireless phones, pace makers and biomedical implants. It needs proper shielding.

I've built my entire shop out of metal siding that is grounded. I've set off 1026 J arcs and checked my building for leaks. Checks good. I used metal doors with grounding straps attached.
The isolation issue is handled really well by putting two mots back to back for isolation.

The grid will not see 500ma dc in the Hester style pulse unit. The output transformer will only allow
16 ma (continious) at the most to the grid (30:1 trani). The unit that I intend to power this unit with is a 3 mot supply with a trippler for a total of 15 kv to the pulse unit. (about 1/2 the voltage a color set runs at)
When it is stepped up the total voltage is 450,000 volts at 16ma. So the unit will deliver 7,200 watts. It will draw 7.2 kw at the input side. The meter will spin merrily.. when this unit runs. I've got a 100amp mains
working with 000 wire from the meter.... the unit passes the power delivery test. At a pulse of a millisecond the total watts will be 7.2 million watts. pulse. Well within the operating parameters of the F-211 thyratron. .
It's a begining.

Larry Leins
Fusion Tech
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Re: Why pulsed power needs 500 ma:top pix

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Here's a pic of a plain jane MOT bank with Tripler.

110 in 18kv out 500 ma.
We bite hard...I built this beast for the first pulse supply
not shown is the 110 volt variac for voltage control and a ready halon fire extinguisher just in case.

Larry Leins
Fusion Tech
Attachments
mot2.JPG
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Re: Why pulsed power needs 500 ma:side pix

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Here is a side shot.
This unit was built out of a cheap dresser top.
It is to be mounted in the vertical inside a wooden fish
tank stand. The pulse unit will reside in a 15 gal fish tank in about 10 gallons of mineral oil.

Larry Leins
Fusion Tech
Attachments
mot.JPG
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Re: Why pulsed power needs 500 ma:side pix

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Larry,
You will not need to put this in oil. This is an exact duplicate of a cap-charger I made about 3 years ago. It worked just fine.

Mark Rowley
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Re: Why pulsed power needs 500 ma:side pix

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Thanx Mark:

It runs pretty well with three MOTS.
I've had few problems with it so far.
Did you get those pdf files?
How long did it take to charge your large cap (Aerovox)
That design is the safest device for very high voltage pulsed stuff I seen yet.
You could just tank the output coil and run in air but
the pfn gets warm and so does the thyratron I using.
Forced air would really be tricky above 12 kv, so rather cause a problem I just dumped the whole rig in oil.
The deck runs at a maximum of 15 kv and the output coil can reach higher voltages as its size grows.
X-ray at the peak voltage would require around a quarter inch for this old chicken.

Larry Leins
Fusion Tech
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Re: Why pulsed power needs 500 ma:side pix

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The Aerovox you saw in the picture was not used with my old MOT setup. That cap is 40kv at 14mfd. Probably better suited for pulsed fusor work than shrinking quarters.

My quarter shrinker used a series of 8 Cooper Power System utility pole capacitors. They were all rated at 47uf each at 10kv. In parallel that gave me 384uf to play with. I started using one 12kv 30ma NST. It took forever to charge and never went to full capacity. The quarters never shrunk very well and the work-coils never totally exploded with force. It was obvious that using an NST was like filling the Grand Canyon with a tea spoon.

With my MOT setup, it charged for about 15 seconds and the spark gap closed. My small pop with the NST turned into a cherry bomb with copious amouns of shrapnel. Tiny small pieces of flattened #10 solid were embedded in the sheetrock and the quarter reduction was better than 50%(dime size). Its a good thing I energized the system via remote control from outside the closed garage. From then on I used a piece of 6" rigid conduit(vented) to contain the work-coil. Even with that, I still discharged the system from outside via remote.

From then on, I have learned to dislike NST's quite a bit. Other than jacobs ladders, small tesla coils and to energize a neon sign, Im not sure what else their good for.

Keep up the good work Larry. I believe you have got us all sitting on the edge of our seats !

Mark Rowley
Garage Scientist (Unlicensed)
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