Go Down

Topic: Thomas Edison vs Tesla (Read 1 time) previous topic - next topic

cjdelphi

Edison and westinghouse pitched the ideas for a Generator, tesla high voltage ac, edison low voltage dc.

Great shows were put on, electrocution from both power sources, DC was supposed to hurt but not kill you... well I've been zapped a couple of times at 240ac but I've felt my muscles contract from the sparks from battery terminal clips when high current flows...

So it begs the question a high powered dc low voltage placed near your heart, this should be able to kill?

Henry_Best

I can't comment on the safety aspect, but just imagine the size of the conductors in the distribution grid if we'd have gone the DC route. There wouldn't have been enough copper in the world.

MarkT

Absolutely, electrocution is indeed possible with DC (it causes more muscle contraction than AC), both AC and DC kill.

BTW DC power transmission is employed, the problem is the large cost of 100kV inverters to convert back to AC
A common use is to bridge between countries that use different line frequencies or to decouple segments of a power
network so they don't have to be phase-locked.
[ I won't respond to messages, use the forum please ]

elac

#3
Jan 15, 2014, 03:42 am Last Edit: Jan 15, 2014, 03:44 am by elac Reason: 1
High voltage high current DC can stop your heart.
Think of TV tube caps.
But while pondering the question, a bit of comic relief- Edison Vs Tesla
It's all about the skills

Graynomad

Quote
decouple segments of a power network so they don't have to be phase-locked.

Is that how they connect all those wind turbines?

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

SirNickity


Graynomad

I don't know if it's all true but it makes me mad every time I read that.

_______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

AWOL

Quote
So it begs the question a high powered dc low voltage placed near your heart, this should be able to kill?

Fibrillation can start from as low as 150uA applied at the heart.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

retrolefty


Quote
decouple segments of a power network so they don't have to be phase-locked.

Is that how they connect all those wind turbines?

______
Rob


Actually any and all types of power generator plants that are to supply power to a common 'grid' must be phased-locked with the grid.


MarkT



Quote
decouple segments of a power network so they don't have to be phase-locked.

Is that how they connect all those wind turbines?

______
Rob


I think it varies.
Quote


Actually any and all types of power generator plants that are to supply power to a common 'grid' must be phased-locked with the grid.



They will be phase locked whether they like it or not - failure to do so blows
the fuses since an efficient generator set can carry vastly higher than normal
currents if mis-phased.  A series of generator sets on the grid has been likened
to a row of heavy pendulums connected by cotton thread - if they are not in
synchrony something breaks.
[ I won't respond to messages, use the forum please ]

retrolefty




Quote
decouple segments of a power network so they don't have to be phase-locked.

Is that how they connect all those wind turbines?

______
Rob


I think it varies.
Quote


Actually any and all types of power generator plants that are to supply power to a common 'grid' must be phased-locked with the grid.



They will be phase locked whether they like it or not - failure to do so blows
the fuses since an efficient generator set can carry vastly higher than normal
currents if mis-phased.  A series of generator sets on the grid has been likened
to a row of heavy pendulums connected by cotton thread - if they are not in
synchrony something breaks.


Correct. Starting up or shutting off a plants grid connected generator is a very structured process often done in coordination with grid operators to slowly ramp up and down power as such generators cannot do 0-100% and 100%-0 instantaneously. First step is to syn up with the grid and then manipulate the generator's phase control to force a specific amount of current onto the grid.

KeithRB

Quote
I can't comment on the safety aspect, but just imagine the size of the conductors in the distribution grid if we'd have gone the DC route. There wouldn't have been enough copper in the world.

Some of the super high voltage transmission lines are DC now. To bring DC to the home requires highly efficient DC-DC converters, however. In the beginning, transformers were a very nice way to transform voltages up and down. To do this with DC requires high voltage semidonductors.

Boardburner2

Ther used to be a dc link between england and france to make best use of nuclear plants i think.

TomGeorge

Hi, there is a HV DC link between Tasmania and Victoria.
In the cases I have seen,  Wind Turbines in a wind farm supply a common HV DC bus then it is cycloinverted into the national grid.

Tom...... :)
Everything runs on smoke, let the smoke out, it stops running......VK3DMK

retrolefty


Hi, there is a HV DC link between Tasmania and Victoria.
In the cases I have seen,  Wind Turbines in a wind farm supply a common HV DC bus then it is cycloinverted into the national grid.

Tom...... :)

Never heard of a cycloinvertor.
Wikipedia says that cyclonconverter is used to convert AC to AC not DC to AC?

http://en.wikipedia.org/wiki/Cycloconverter

Go Up