High voltage poll

I am obsessed with high voltage power lines and insulators; lots of the times when i am driving i get distracted looking at insulators. when it is raining i often pull my card under high voltage lines to listen to the corona=) Here in NJ we have some awesome 500kV lines!

I did a report in school about some 365kv lines that I thought were too close to some street lamps.

Here is one of my favorite high voltage line inspection videos:

[media]http://www.youtube.com/watch?v=9tzga6qAaBA[/media]

yea i'm like that too, staring out the window at the transformers and stuff. actually i found some insulators down at the tip, and they were MASSIVE and heavy i didn't buy one though, it wouldn't fit in my car ;D

c0ldshadow said:

I am obsessed with high voltage power lines and insulators; lots of the times when i am driving i get distracted looking at insulators. when it is raining i often pull my card under high voltage lines to listen to the corona=) Here in NJ we have some awesome 500kV lines!

I did a report in school about some 365kv lines that I thought were too close to some street lamps.

Here is one of my favorite high voltage line inspection videos:

[media]http://www.youtube.com/watch?v=9tzga6qAaBA[/media]

Click to expand...

HOLY FREAKING CRAP!!! I WANNA DO THAT!! OH MY GOD

This guy has a heart of steel! He must have some solid set of nerves to rely on the pilot of the chopper to hold him still enough and to believe that the suit/wires will keep him alive! WOW!

Thank you for posting that... Favorited... instantly!

--DDL

That is truly amazing ;D does he use that stick to charge and to discharge the helicopter to the same voltage as the lines?

I am guessing if there is no potential difference in voltage then a current cannot flow, thus protecting them from harm. I can imagine the avionics on that helicopter must be bullet proof insulated from the Chassis.

Great Video.

Jase

I'm pretty sure they use the metal pole to equalise the voltage between the guy and helicopter. If they didn't do this, the crackle would come from his hand, which I'm told would hurt like hell (but not otherwise harm you).

I love high voltage stuff and have quite a collection that changes frequently. My favourite little gadgets include a little potted module with a 5-15V input and up to a 6,000V output and a 10,000V from 9V inverter circuit.

The camera flash circuits are also incredibly fun and useful. Take off the big capacitor and you have a charging unit for bigger caps, or use it to shock your buddies  ;D
The size of the components is incredible too. As there are only 4 components you need including the transformer, you can solder the other 3 to this. The full circuit can fit in a biro lid!

I've lost count of how many circuits I've built or acquired that put out a lovely bang. The highest voltage I've had out of such a circuit was estimated to be about 45kV (extremely low current of course!)
Someone did give me the circuit from a stun gun that I powered from my bench supply that apparently put out 650,000V. While it made a lovely noise, the longest spark gap being about 1 and a quarter inch suggested to me that it's really nothing like that.

I've also charged some huge caps over a few minutes and fired them through a spark gap. Now THAT is high voltage at it's craziest! The 1 Farad cap I had comes to mind that vapourised the balls on my spark gap arrangement 3 times before splitting!

the highest voltage i think i've played with is something like 100kv from a REALLY high powered flyback circuit

ha i just checked the votes, and no one has said it's boring!?that's nice to know!!

Tallaxo said:

That is truly amazing ;D does he use that stick to charge and to discharge the helicopter to the same voltage as the lines?

I am guessing if there is no potential difference in voltage then a current cannot flow, thus protecting them from harm. I can imagine the avionics on that helicopter must be bullet proof insulated from the Chassis.

Great Video.

Jase

Click to expand...

all helicoptors need to be grounded after flying. They build up HUGE amounts of static electricity. When helicopter come to do a tether you have to use a ground rod and hook the helicopter's line and it also ground the helicopter, I've heard it crack a couple of times a hundered feet away ( over the noise of the chopper ) if the conditions are right. It's enough of a static discharge to kill someone. Probably the same for the power lines.

The worry about the power lines with high KVA ratings isn't that when flying up in a helicopter and then touching them, that shouldn't do anything ( same reasons why squirrels and birds can be on them ). The problem is more likely that the helicopter can be close enough, along with the guy to arc between lines. The suit is also to protect the guy if he gets too close to a pole or another line. The lines will arc to each other, and the poles if they ground. The helicopter can via static electricty ionize the air enough that arcing can be a problem and let it jump much eaier.

Years ago I made a Jacob's Ladder out of a neon sign transformer (big one, about 40 lbs) and some 6-foot long copper tubing.
By the time the arc reached the top it'd be about 5" across.
I used to run a sheet of paper through the arc, then see the 60Hz perforations. Or hold it still and set it on fire.
Did lots of playing around with HV stuff when I was into He-Ne lasers.

In my garage I've got an antique shipboard motorized spark-gap transmitter with a telegraph key. If I ever want to obliterate all the TV signals on my block, all I have to do is fire that thing up.

Always wanted to build a Tesla coil but never got around to it.

well, might as well ask here: I have a microwave transformer here, giving me (theoretically) 2kV @ ~1400W. Now, I for HV experiments, I use my oil burner transformer, because it is "shorted-protected" (or whatever), meaning the fuse won't blow if I have a spark (= close-to-zero resistance). But that transformer was built to be shorted.

Now, if I make sparks with my microwave transformer, will it blow my fuse? Is there a short circuit portection, will it limit the current, will the secondary voltage cave in? Or am I going to have a nice, stable spark?

philguy said:

well, might as well ask here: I have a microwave transformer here, giving me (theoretically) 2kV @ ~1400W. Now, I for HV experiments, I use my oil burner transformer, because it is "shorted-protected" (or whatever), meaning the fuse won't blow if I have a spark (= close-to-zero resistance). But that transformer was built to be shorted.

Now, if I make sparks with my microwave transformer, will it blow my fuse? Is there a short circuit portection, will it limit the current, will the secondary voltage cave in? Or am I going to have a nice, stable spark?

Click to expand...

those are some of the deadliest / most dangerous transformers you can find easily, use extreme caution!

You're likely to get > 0.5A out of the secondaries. MOT's are not current limited like a Neon Sign Transformer (NST) or Oil Burner Ignition Transformer (OBIT). The secondaries will likely get very hot very quickly and the initial surge might trip the mains circuit breaker. These things produce enough current to kill you 10 times over. Be careful!

If you want to current limit the MOT, you can always add a heater element (high resistance winding) in series with the primary winding (from a hair dryer, toaster - something designed to glow when 115v is run through it.) By limiting primary current you'll limit secondary current.

oh yeah, as others have said, MOT's are the most deadly transformer one can get, apart from the pole transformers! you can easily get over 1A from a unballasted MOT, which will kill you before you touch it basically. i have heard of one person who accidently touched the leg of a pole transformer for his tesla coil, and it threw him onto the ground. he woke up like 4 hours later! you would be VERY VERY lucky to survive something like that! personally i have touched a 15kv 30ma NST, and it hurt REALLY REALLY bad, but it just got me across the arm luckily. i don't think it was actually outputting 15kv, as they have been playing up, but it definately was 15ma!

Uh, thanks so far. Well I guess these beasts are more dangerous than I thought. It already killed my DMM accidentally
So far I used a 200W(?) Transformer giving me 15V on the secondary side, hooking that up to the MOTs primary, but all it did was smoke my cables (not thin ones!).
But I didn't have the guts yet to connect it directly to 230V.

I have a Metal halide ballast lying around, designed for a 250W lamp, will that limit current, too? As I do have a resistor, but am not all too keen to get it glowing or sth.
Might try a heating element (same microwave, was a stove, too).


Well, so far I've only worked with an OBIT, and that was designed for arcing, and gave me "only" 25mA. Seems this is a whole different class (Class IV Transformer, max. Output >500mA ).

I've heard stories of electricians DIEING from MOT's... they are the MOST dangerous thing i can think of (Well, them, sharks, guns, etc).

if you can definitely get something like an oven or toaster and put it in SERIES with the transformer - but BEFORE the primary coil on it - ensuring limited current through the MOT.

Secondly - if not MORE importantly, the circuit breaker to your house WILL NOT TRIP if you present a path to ground for that transformer's secondary coil (through your body). this is because of the circuit isolation through the transformer core.

This means that if YOU go live   and are left as a smoldering corpse and remain incontact with that transformer - anyone that touches your deceased remains may also be electrocuted. :'(

(although i don't know what the conductivity of a smoldering corpse is, but i'm sure with all that carbon - it would be only a few ohms) :-?

uah, no worries there...
Okay, my respect for that buddy keeps on increasing... gonna put some limiting factor there. Yeah, I have something in mind, old oven.
Gotta try that now. Some time. Maybe tomorrow. Or later.


edit: well, I did it. I did not use a resistance element, though. What I did was a) use a different circuit breaker circuit (whatever it is called), and b) by using some weird lego-arm-contraption I once built for such purposes (shorting HV caps etc.), which is basically a long arm.

So, it surprised me that it barely arcs. One needs to almost connect two tips to get it to arc. I was also surprised then to see the arc flare out to an approximately 12cm (4.7 in) flame-coloured discharge. It was all cool and the like, with melting the tips of screws by the arc (but the cables leading from the MOT to the srews never even got the slightest heat!), until the MOT itself was smoking...that's when I decided to maybe stop and let it cool down a bit