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ragnar

Sun Apr 01 2007, 11:39PM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Great Scott, that is impressive.

Big pulse capacitor?

Scott Fusare

Mon Apr 02 2007, 08:54AM

Registered Member #531 Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125

I am using a pair of 230 Î¼F 7kV pulse caps wired in parallel. This is close to what the original (Russian) researchers used.

Chris â€“ I do intend to try out different salts as colorants. The brilliance of the initial flash, and to some extent the fireball, tends to saturate both eyes and camera so some experimentation will be required.

Daniel Uhrenholt

Tue Apr 03 2007, 07:58PM

Registered Member #125 Joined: Fri Feb 10 2006, 01:52PM
Location: Aalborg, Denmark
Posts: 155

Guess what this is

I can tell you that it`s something I work with every day

Sparking all the time, Daniel

Tonic

Tue Apr 03 2007, 09:02PM

Registered Member #528 Joined: Fri Feb 16 2007, 10:32PM
Location: Warsaw, Poland
Posts: 166

I'll take a shot - is this a plasma cutter?

Daniel Uhrenholt

Wed Apr 04 2007, 01:53PM

Registered Member #125 Joined: Fri Feb 10 2006, 01:52PM
Location: Aalborg, Denmark
Posts: 155

nope

It`s a ED wire-cutting machine.

It is also called EDM (Electric Discharge Machine) cutting.

The machines I work with is extremely accurate, they are used for high precision workpieces in the tooling industry. They make a very fine surface on the iron, cobber, brass, graphite or tungsten or whatever we cut in.

It`s a great tool to have if you need to cut some tungsten electrodes

Daniel

Ken M.

Wed Apr 04 2007, 02:10PM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

but isn't a an electric discharge from a TC or Flyback or MOT Plasma just so long as it gets hot enough?

Daniel Uhrenholt

Wed Apr 04 2007, 02:32PM

Registered Member #125 Joined: Fri Feb 10 2006, 01:52PM
Location: Aalborg, Denmark
Posts: 155

Hi HVAC Plz.

This machine don`t use high voltage, but high current pulses. The machine i work with has 8 Class D amplifiers, that generates up to 700A pulses through a capacitor circuit.

Here is a link to a explanation:

Cheers, Daniel

Ken M.

Wed Apr 04 2007, 09:48PM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

OHHH ok, i was just thinking that they were simmilar, with the energy and power used. but thanks for the link and clarified explanation!

Marko

Fri Apr 06 2007, 07:21PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

This machine don`t use high voltage, but high current pulses. The machine i work with has 8 Class D amplifiers, that generates up to 700A pulses through a capacitor circuit.

Ok, but there must be a pilot HV transformer wich starts up the arc?

And what class D amps have to do with it?

Daniel Uhrenholt

Fri Apr 06 2007, 09:02PM

Registered Member #125 Joined: Fri Feb 10 2006, 01:52PM
Location: Aalborg, Denmark
Posts: 155

Hi Firkragg

This is what I learned a few weeks ago about the machine:

There are no transformers in the machine, itâ€™s all Solid State. There is a big switch mode power supply in it. The old ones are based on Class A amplifiers, and they have a BIG transformer in them (in our case 3phase) they are from the 80ies

The Class D amplifiers make the high current frequency (or what I call pulses) that moves material from the work piece. There is a â€œspark gapâ€ between the thread and the work piece, itâ€™s about 0.2-0.05mm, but the gab depends on the power setting on the machine.
I need some pictures from a book from work, if you want to know how it starts the sparkâ€¦

When a spark flies from the thread to the work piece, some material are vaporized and moved from the work piece. This happens many times per second, itâ€™s not a fast way to make things in metal, but itâ€™s one of the most precise.

It can â€œfeelâ€ how close the thread is from the work piece, and then it will back off if itâ€™s too close, and release a pulse. I donâ€™t quite understand how it can do this, but it can

Because sparks develop lots of heat, itâ€™s all under distillated water with â€œdielectric powderâ€ (I donâ€™t know the English word for it), and an insane water filter system that keeps the water clean.

And a big cooling system, the work piece must have a temperature about 20degrees celsius, or else the machine will shut down. This automatic shutdown happens because if it gets warm, the metal will expand and then we canâ€™t hold the tolerancesâ€¦

I donâ€™t have any pictures of the On and Off time and duty cycle of the machine, but I can get it next week.

I will copy some of the pictures from my theory book and post them if you like. Or maybe measure some myself with my scope and differential probe.

Cheers, Daniel

BTW, the 700Amps are the peak current.

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