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Looking at arcs !?

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ZakWolf

Sun Aug 29 2010, 03:55AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

my parents are worried that the my ZVS driver arcs are hurting my eyes. they are comparing my ZVS arcs to an arc welder. i have researched that the arc weld arcs are not safe to look at because the metals are being melted and is burning per say, so it produces a bright light that is bad for eyes. On the other the ZVS arcs are ionized gas that are dimmer then a lighter flame, if any one knows about high voltage arcs not arc welder please let me no.

Matt Edwards

Sun Aug 29 2010, 04:22AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

It is my understanding that the UV produced by the arcs can potentially cause damage to your eyes.

Proud Mary

Sun Aug 29 2010, 05:16AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

We can divide the UV emissions of an electric arc into two classes:

1. Thermal UV emissions occur when photons are emitted due to changing energy states in a material. Above about 3000 K, sufficient UV is emitted to be a health concern.

2. UV emissions resulting from the de-excitation of atoms first raised to a higher energy state by ionisation of a gas, air at atmospheric pressure, in your case.

The emission spectrum of your ZVS arcs will contain UV emissions from excited N atoms in the air - 337 nm - as well as whatever metals your electrodes are made out of.

Whether your exposure is likely to be long enough and often enough to do you measurable harm is another matter. On the balance of probabilities I would think you were more likely to be charred by RF burns, or by setting fire to yourself, or being murdered by your neighbours for interfering with their TV reception, but who can say?

Patrick

Sun Aug 29 2010, 07:49AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

short exposure on the order of 30 seconds every other day is my personal limit. (@ about 3 feet or more)

Dave Marshall

Sun Aug 29 2010, 08:04AM

Registered Member #16 Joined: Thu Feb 02 2006, 02:22PM
Location: New Wilmington, PA
Posts: 554

Proud Mary has a good point, but keep in mind that the process of welding is designed to produce as much heat as humanly possible. A side effect of this is large amounts of light. Welders also typically operate in excess of 1800w, with large arc welders approaching 5kw. I haven't seen a great many ZVS drivers that can even fantasize about that much power in the darkest recesses of their little silicon hearts.

In all the HV tinkering I've done over the years, the only thing I ever managed to construct that had a legitimate amount of UV production was a pair of MOTs in series, pulling close to 4kw. If an arc was struck short, and the electrodes were kept very short, it was bright enough to cause mild welder's flash.

A pair of polarized sunglasses probably wouldn't be a terrible idea if you're up close and personal with the thing, and running it for more than several minutes a day. Even a pair of untinted UV blocking safety glasses should do just fine, considering the arc most likely isn't bright enough in the visible spectrum to cause damage.

-Dave

doctor electrons

Sun Aug 29 2010, 02:21PM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

If you are even the slightest bit worried about damaging your eyes you should do this.
Look on the internet or go to a welding supply store, pick up a pair of torch cutting glasses
in a shade anywhere from shade#3 to maybe#6. Try them on and see which ones will work for you.
The most common shade for arc welding is #10, when you put it on in full sun you can almost see.
Shade #3 will protect your eyes and its the only pair you get, better safe than blind at an early age.

Heres a tidbit from my past, the most common reason a welder will get flashburn is not from the arc
in front of his helmet. It is from refracted and reflected light entering the back of his helmet, reflected off
the lens and into his eyes. Flashburn is very painful, any good welder knows to hang a cover over the back
of his helmet!

dmg

Sun Aug 29 2010, 02:34PM

Registered Member #2628 Joined: Fri Jan 15 2010, 12:23AM
Location:
Posts: 627

I second doctor electrons suggestion with the #3 shades, comparing an oxyacetylene torch to a ZVS arc,
the torch is far brighter then those arcs. (maybe a spark gap of a decent power TC is an exeption)

the other neat thing with #3 shades, they still let you see everything around you and work very well for HV arcs, if you find it not enough for yourself, can always try a shade or two higher (#4, #5).

Adam Munich

Sun Aug 29 2010, 02:43PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I always wear UV blocking sunglasses when playing with an MOT, and let me tell ya, it definitely helps!

radiotech

Sun Aug 29 2010, 02:56PM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

my parents are worried that the my ZVS driver arcs are hurting my eyes. they are comparing my ZVS arcs to an arc welder
There are two issues here. Firstly, the characteristics of an arc welder and the methods to protects they eyes are well known. The ZVS ark is not is not. The reason is the welding industry is locked into a loop that includes safety accountability. Your ZVS arc may be as harmless as a fireworks display. But home experimenters may create devices that can damage eyes. From what I've seen on U tube people seem to delight in pulling arcs at arms length with flexible ground or return leads. I imagine there may be others watching too. So best plan is to buy a welding face guard, one with flip up darkened plate. And get into the habit of wearing it whenever your arc sytem is energised. The fact that you are wearing it will signal to others that there is some cautions involved here.

Looking back to your age (and inclination) I do remember pulling arcs with carbon rods from dry cell batteries, powered by the high voltage winding on a radio power transformer and getting a severe ultraviolet burn in the face and eyes that didn't hurt at first but sure did in the middle of the night. In those days people didn't run to hospitals with every little injury, especially kids.

BOO !

Adam Munich

Sun Aug 29 2010, 03:03PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

That is a little overkill IMO. The arcs of even an MOT are nowhere near as intense as an arc welder. Just wear some really dark sunglasses that block UV, and you will be able to see what you're doing! I don't believe that near blindness (welder's goggles) and high voltage go very well together at all.

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