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Myke

Mon Feb 09 2009, 02:41AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

teslacoolguy wrote ...

I am pretty sure it is impossible to "vaporise" a hot dog with 2kv at 1A. I think you are better off going with a large capacitor bank that will pulse tens of ka of current at a high voltage.

It's funny how hard it is to destroy a hot dog. IIRC TDU discharged his cap bank into one and it didn't do anything.

Frosty90

Mon Feb 09 2009, 07:38AM

Registered Member #1617 Joined: Fri Aug 01 2008, 07:31AM
Location: Adelaide, South Australia
Posts: 139

I've found that HID lamp ballasts are really useful for ballasting mots. If i want to draw arcs/cook stuff, i use two mots with their secondaries in series and the primaries in parallel, balasted with a 2000watt lamp ballast, with 240 volts in (these are 240volt mots) and the output shorted it draws about 10 amps and gives some nice arcs

Dr. Dark Current

Mon Feb 09 2009, 10:17AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

cduma wrote ...

I dont think it will draw anywhere near 40A because I have shorted it out and my breakers are only rated for 30A. Maybe I need to change the breakers out...

I dont want to cook the hotdog. I want to vaporize it!

My 10A breaker does NOT trip when drawing arcs off a MOT which draws ~20A (from 240V). The breakers have some "current inertia", a 30A breaker will probably sustain 40A draw for about a minute.

Frosty90 wrote ...

I've found that HID lamp ballasts are really useful for ballasting mots.

If you have one... but if not, it's 10 times cheaper to just get a few more MOTs and connect them as a ballast.

LithiumLord

Mon Feb 09 2009, 11:02AM

Registered Member #1739 Joined: Fri Oct 03 2008, 10:05AM
Location: Moscow, Russia
Posts: 261

Well, we've been frying hotdogs on an unballasted MOTs (had the chokes in of course) when were drunk on my b-day once, we overheated the MOT however (didn't watch out well enough and we were too many so needed to make quite some runs of this setup) - but it worked straight the way we wanted it to as the hotdog survived and also got fried krispy and tasty. In order for the best cooking process you'll need to wrap it's ends with a metal tape and use it as input terminals.

Tom540

Mon Feb 09 2009, 09:45PM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
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Posts: 617

If you want to vaporize something then build a cap bank and discharge it through the hot dog or pickle.

Backyard Skunkworks

Tue Feb 10 2009, 05:59AM

Registered Member #1262 Joined: Fri Jan 25 2008, 05:22AM
Location: Maryland, USA
Posts: 451

I hate to go bursting your hotdog exploding bubble, but you can't get past the physics of this.

I did a little googling and found out that your average hotdog is somewhere around 50 grams. Now for the sake of this model, lets call the hotdog 100% water, I know this is pretty far off, but it will still give you an idea of how much energy would be require to pull this off...

If we need to vaporize 50g of water, which works out to 2.77 mol, we need to heat it to 100C and then boil it.
Each mol of water takes 75.4J to rise in temperature 1C, and 40,650J of energy to transition from liquid to gas.
If we need to raise the water's temperature by 80C and have it vaporize, we're talking about nearly 47kJ per mol.
Given that we're talking about 2.77 mols, we would need nearly 130kJ of energy to instantly vaporize that quantity of water.

Now all that being said, technically vaporizing 50g of water and making a hotdog dissapear are two differnt things. I think having a hotdog explode into a bunch of little bits will appear just the same, and may be possible with just a few kJ.

A few MOTs in parallel may give the desired effect. While this won't vaporize the hotdog, it will boil it quickly and probably make it explode in several pieces.

LithiumLord

Tue Feb 10 2009, 02:18PM

Registered Member #1739 Joined: Fri Oct 03 2008, 10:05AM
Location: Moscow, Russia
Posts: 261

Well, that vaporization idea feels good for a school demo project only in case "demo" is taken as a short for "demolition", not "demonstration" ;)
Even a 500J discharge will sound really loud, now add UV protection and other protective stuff (well, that may become one of those things that are both sad and funny if someone gets killed with a hotdog fragment lol).
For eye candy, I'd go with some arc experiments, however the idea of cooking a hotdog is way more profitable as it's like "Haha, we geeks eat tasty stuff while you suckers have to watch us do this on a boring physics lesson" lol.

Lakeowner

Tue Feb 10 2009, 02:26PM

Registered Member #1370 Joined: Mon Mar 03 2008, 09:01AM
Location: Finland
Posts: 56

This is how spectacular it appears IRL:

EEYORE

Tue Feb 10 2009, 06:09PM

Registered Member #99 Joined: Thu Feb 09 2006, 06:10PM
Location: florida, usa
Posts: 637

Laakkonen wrote ...

This is how spectacular it appears IRL:

That was pretty lame, and it made me feel kinda weird inside while looking at the hotdog for some reason (almost as if the hotdog was staring back at me?)...I think using the MOT in the actual uWave would be more spectacular. If your looking to impress, just make a jacobs ladder.
Matt

cduma

Mon Feb 16 2009, 08:17PM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
Location:
Posts: 300

When I vaporized the hotdog I touched my hv probe(Nail on a peice of PVC) to one end and there was a lot of smoke and where ever i touched there were hotdog parts missing

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