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Exploding wires - duelling machines

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LAN_403

Tesladownunder

Sun May 21 2006, 09:55AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Love this shot. It's just like the game Total Annihilation with the Arm machines vs the Core machines burning each other up.
It actually is an exploding wire run through an inductor. The inductor is a 3kV winding of a 10kW transformer. Wire is 35G and power is 2.5kJ at 5.5kV. Details of the previous setup are here on the previous forum.
Look at the right "machine" which is just a 100kv mobile x-ray supply which is also supporting the unrelated transformer. The flash seems to envelop the transformer. I wonder if this is due to the magnetic fields as it is not present on a shot without the inductor but arising from the same spot.

Peter

1148205320 10 FT0 Pulsecapexplodingwire35g2kjinductor

1148205320 10 FT0 Pulsecapexplodingwiretransformer

ragnar

Sun May 21 2006, 10:55AM

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

But Peter... it's not April fools' day..

Tesladownunder

Sun May 21 2006, 11:14AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Ummm.. Does that mean you don't believe this is a bona fide shot or just the reference to the game? I may be devious at times but I don't have Photoshop.

Another shot from a different angle with the same power, hoping to characterise the plasma around the transformer. You can see the flash around the transformer particularly going upwards. I don't think that it is a flashover across the inductor on this shot.
My suspicion is that it is the plasma channel being forced in one direction parallel to the axis of the coil due to the whatever-hand rule as the current in the channel is coming out at right angles. As the voltage reversal occurs the flash heads in the opposite direction.
What is also interesting is the vibrations in the string caught in the blue flash. There are harmonics as well since it is not a clear sine wave. (My version of "string theory").

Peter

1148210045 10 FT9887 Pulsecapexplodingwire35g2kjinductorfront

Marko

Sun May 21 2006, 11:24AM

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

Don't you fear of ruining the transformer that way?

Tesladownunder

Sun May 21 2006, 11:42AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

The transformer winding is very solid and epoxy encased for the 3kv AC which is about 5kV peak which is what I am putting into it as DC.
I'm not scared. It has just been a boat anchor until now.
If I have voltage issues I have other higher voltage transformers.

The reason I got onto this today was a failed attempt to pull out long arcs by pushing 5kV through the coil then physically breaking the circuit with a spring loaded make and break switch. It was really dissappointing and I expect there is a clear optimum of make to build up the current in the transformer to a peak then rate of break to allow the energy in the coil to maintain the voltage and current to draw the arc. I was getting voltage reversal on my meter so was probably holding the make too long. I didn't really take any photos of the setup as I was hoping for good results around dusk when lighting is optimal for these type of things.
Mind you the transformer will only store 200J of magnetic energy (10KVA divided by 50Hz).

Pic is a very old one with my pulling an arc off it when it is ballasted using apalling safety procedures.

Peter

Marko

Sun May 21 2006, 12:20PM

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

Damn, I would like to have a such core at least!

Probably not fun to you after having all theese beasts...

Steve Conner

Sun May 21 2006, 03:55PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Transformers store hardly any magnetic energy, because the core doesn't have an airgap. I doubt it stores anywhere near 200J. If it did, it would draw 10kVA worth of magnetizing current when connected to the supply but unloaded.

Hazmatt_(The Underdog)

Sun May 21 2006, 06:38PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I know that picture is old and all, and ballasted...well okay maybe that would save your life, but what I wanted to say is this: Just because you have a ground wire on one side of the transformer don't think that tells the transformer its at 0V! because its not. This is a really bad practice for those new guys out there who are going to think that it works that way and could get killed by the HV on the lead.

Pictures like this worry me to no end.

Marko

Sun May 21 2006, 06:59PM

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

I couldn't recognize the connections from the pic, and I don't know if you could.

Secondary could be one side grounded, centertapped or not grounded at all.

If the wire he's holding in hand is really internally connected to ground he could blow up only by touching another electrode.

If it's center-tapped and apalling safety procedure conducts he again blows up.

If secondary is hanging he will probably get just a relatively minor displacement current shock,
probably not fatal and dependent on capacitance between secondary and earth.

Dr. Dark Current

Sun May 21 2006, 07:56PM

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

Firkragg wrote ...

... he could blow up only by touching another electrode...

... he again blows up.

sorry but this just made me laugh

I dont see how Matt's post makes sense.. from the picture it is apparent that he's holding an insulated "stick"

J.M.

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