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Hot Plasma!
This sustained arc is at least 5"~6" long! The transformer is from a Sharp microwave oven. Secondary is one loose wire which I am holding, other end is attached to the frame. No idea what the voltage and current is going thru the arc.

This thing get hot after a few seconds of sustained arc. Not suggested to keep the arc any longer than 10 secs or it will burn up.

Any idea what I can do with this thing?
Keywords: Miscellaneous

Hot Plasma!

This sustained arc is at least 5"~6" long! The transformer is from a Sharp microwave oven. Secondary is one loose wire which I am holding, other end is attached to the frame. No idea what the voltage and current is going thru the arc.

This thing get hot after a few seconds of sustained arc. Not suggested to keep the arc any longer than 10 secs or it will burn up.

Any idea what I can do with this thing?

CRT_Super_Macro_Shot.JPG Red_Pickles.JPG Hot_Plasma!.JPG Refurbishing Headlights.JPG Ballast Boxes.JPG
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Filename:Hot_Plasma!.JPG
Album name:FGS / Experiments
Keywords:Miscellaneous
Filesize:32 KiB
Date added:Jun 24, 2010
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Displayed:269 times
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=2285
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Comment 1 to 20 of 20
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DimBulb   [Jun 24, 2010 at 10:57 PM]
Shocked Shocked Shocked
Form109   [Jun 24, 2010 at 11:35 PM]
Most Microwave Over Transformer's (M.O.T's) produce between 2000 and 2500 Volts...Mine was from a 1100 Watt Sharp Microwave who's Magenetron Bit the Dust....it Output About 2500 Ma of current....it Could do about 6 to 8 Inch Arcs....it Tripped a 20 Amp Breaker in under 60 Seconds,so there is some Massive power draw when arcing...it also got Very Hot,in those 60 Seconds you could see a little smoke and smell burning Varnish....i did Ballast mine one Time using a 120/240 1 KW Step Up Transformer...i Fed 120 into the 240 Side,and connected the 120 Input (output in this Case) to the MOT...this enabeled me to run it for about 15 Minutes before it got Too Hot..and also kept it from Snapping the Breakers....im Pretty sure thats not in code but it worked nicely.
RCM   [Jun 25, 2010 at 06:53 AM]
I think this proves that we are ALL nuts! Laughing
dor123   [Jun 25, 2010 at 11:11 AM]
I don't know why this is happens, but most of the arcs that producted by these transformers (Includes these ones of those jacobs ladders) are looks more likely as a double ended flames, with an inverted V shape instead of a real shape of arc and even they have a blackbody continuum spectra, like a real fire flames (I managed to check the spectrum of the arc in the jacobs ladder in the National Museum of Science of Israel, using a CD-R, when i visited with the tenants of the hostel i live. The arc itself have a color of 2500K and the spectrum of the arc looked like a REAL blackbody continuous spectrum instead of atomic line or molecular spectra like in discharge lamps). Why this is happens???
But don't forget: Electric arc is not a consumer like a filament. This is an electric short. so this is why the breaker is tripping when messing with these things. Also because this arc isn't current limited, the transformet gets very hot.
Form109   [Jun 25, 2010 at 03:19 PM]
MOT Transformers do Have Shunts in the cores.....but they don't seem to do any limiting at all.....in a Microwave Oven the Transformer is Wired to a High Voltage Cap and a Diode.....so the Magnetron in the Microwave must Obviously recieve Direct Current...the Cap in Series with the Transformer By itself makes Arcs Greatly Bigger...imagine Wiring a Bank of those Caps with the Transformer.
SeanB~1   [Jun 25, 2010 at 05:44 PM]
Try an arc welder. 50 odd V at up to 130A means you can draw a pretty big arc with it. The arc generally is ionised iron while it is struck, though I did get green when using #12 copper wire to weld thin car steel panels.
FGS   [Jun 25, 2010 at 06:30 PM]
I have the cap that was wired in series with the MOT's secondary and magnetron. Won't shorting out the MOT before drawing the arc cause the cap to explode or something? Info on cap is 2000WVAC 0.72uf. It have an internal resistor from a simple drawing on the cap's case.
Medved   [Jun 25, 2010 at 06:42 PM]
Are you trying to kill yourself, holding the HV wire in your hands? Shocked
This is not an TV with few mA current capability, neither it's the mains with few hundert's V, this is 2kV, few ampere device!

And such experiment severely overheat the transformer secondary, better to keep the ballast capacitor connected...
MOT do not have intentional magnetic shunt, as the capacitor is there to serve as ballasting impedance.
MOT themselves do have an "air" gap in the magnetic circuit, it lower it's main inductance to compensate for the reactive (lead) impedance of the (capacitively ballasted) load. That is the reason, why they fry, when operated in open load: The reactive current from the low main inductance does not come from the secondary (larger, designed for this) winding, so has to come from the primary. And there it cause it's current overload (the primary current is frequently twice on open load, then when normally operating the magnetron).
Silverliner14B   [Jun 25, 2010 at 06:54 PM]
I agree, they are dangerous! Shocked
FGS   [Jun 25, 2010 at 07:00 PM]
My fingers are a couple of inches back from the tip. Look closer than that cuz of the way the wire is facing the camera. And the wire is red with a black cover around it.

This one do have the shunts. I saw them between the primary and secondary. This thing is from a 1100w Microwave oven if that helps tell you what are the rating of this MOT.
Form109   [Jun 26, 2010 at 12:54 AM]
Whenever i Arc with my MOT...i Connect the High Voltage Wire to a Screwdriver.....then i Draw the Arc....i never Trust Holding a Wire For High Voltage...even if the Wire is insulated and your fingers a Few Inches Back...and little bit of moisture could conduct current...not to mention the Insulation might develop tiny Cracks that you cant see....large enough for a spark to jump to your Finger....i got Zapped Badly by mine once....it tops the list on the most Unplesant sensations you can feel. Shocked

Also FGS....im not sure about the Cap....the One on mine Never Blew...mine was Metal Encased....and since it is a High Voltage Cap with a metal Case possibly there was Oil inside for insulation.
gailgrove   [Jun 26, 2010 at 01:55 AM]
Ouch Shocked being shocked by 120 tingles (done it many times) I don't want to imagine 2000 Shocked
joe_347V   [Jun 26, 2010 at 02:19 AM]
Whoa! Shocked I would prefer using a NST instead of a MOT since they limit the current down but still I would be really careful working with all high voltage devices.

I've never been shocked by 120V before but I have gotten shocked by a ~600V CCFL inverter before, It felt like something bit you finger.
Medved   [Jun 26, 2010 at 04:40 PM]
@FGS: Be aware, then MOT generate a lot of heat on the wire tip, what spread and might easily melt the insulation underneath your fingers...

@joe_347V: CCFL run only at ~8mA high frequency, NST at ~30mA.
120V mains would shock you below 100mA (if you do not really hold something), what is assumed as dangerous, but healthy human withstand it for few seconds. But what is dangerous is the muscle response to the shock: It migh caus you to grab the object and you will not be able to release it by your will, so the shocking might then easily endure way longer then few seconds...
But the 2kV MOT would be really able to pass amps trough the body - and i'm afraid, this might really easily kill instantly...
Form109   [Sep 05, 2010 at 06:54 AM]
even with the Capaciator connected my MOT Will still overheat pretty quickly....
SeanB~1   [Sep 05, 2010 at 10:10 AM]
Take your plasma ball, and place a small bunch of grapes on top, only touching the glass. Then you can draw an arc from one of the stems, which will burn a hole in your skin, without any initial pain until you burn though to a nerve ending.

Remember as well that those transformers are forced air cooled in the microwave, as well as being heatsinked to a degree by the chassis it is screwed to. They almost always have a thermoswitch rated at around 135C attached to the magnetron to prevent overheating, you can attach this to the frame with some 2 part epoxy and use it to reduce the probability of the unit overheating in these experiments. The switches are very reliable, and are in all microwaves.
Sailormoon_01_uk   [Sep 05, 2010 at 07:00 PM]
I think you guys are suicidal as it only takes 30 milliamps to kill and 2000 or more volts ZZZZZZAAAAAAAAAAPPPPPPPPPP!

All the Best

Colin
Form109   [Oct 17, 2010 at 06:19 PM]
a few times i forgot mine was turned on and moved it..(ZAP!) Rolling Eyes
Sailormoon_01_uk   [Oct 18, 2010 at 08:23 AM]
I bet you felt it and possibly thrown across the room with your arm throbbing to hours.
Form109   [Oct 18, 2010 at 08:22 PM]
actually at the time the Transformer was ballasted to a Fraction of its potential output current....so all that was felt was a tiny tingle...the startle of the shock...even though small causes a sudden jerk of the arm.

Comment 1 to 20 of 20
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