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More than lead and elbows
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579 Posts
It all depends on the notation you choose to use, conventional flow theory vs electron flow theory.

Conventional flow uses the positive terminal to indicate an excess of electrons, flow of electricity is to the deficient or negative terminal.

Electron flow theory uses the negative terminal to show a negative charge i.e. electrons, flow is to the positive terminal, positively charged end. This is the actual flow of electrons, from negative to positive.

Most engineers use conventional theory I believe.
 

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Electron Factory.Worker
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253 Posts
So, one of my classmates had a fundamental question of where electricity comes from. The best anyone could answer was that it came from a generator, but we were looking for a more in depth discussion. I understand that a turbine spins a turbogenerator, spinning a set of wires past magnetic poles, but with that in mind, all I could see happening would be a back and forth motion of electrons, and no electrons actually being created and pushed down the wire. I'm sure there's a big hole in my understanding, and I was wondering if anyone would like to fill me in on the reality.
Technically on a 3 phase generator the magnetic poles actually spin around and the conductors are stationary. A DC current is supplied to the rotor which creates a magnetic field. As the magnetic field sweeps around the magnetic field is cut by the the stator windings which induces a voltage in the windings. The electrons will "pile" up as the magnetic field peaks and then be reduced to zero and swing to the opposite direction continously. It gets much more complicated with the load control voltage control etc. but this is the gist of it.

It may seem like a zero sum game, but consider a sawzall vs. a band saw. A sawzall goes back and forth returning back to its original position (AC), but it still does work (cutting the wood). A bandsaw goes in the same direction continuously (DC) and cuts the wood. They both do the same work but achieve it in different ways.
 

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zap
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1,327 Posts
scameron81 said:
Technically on a 3 phase generator the magnetic poles actually spin around and the conductors are stationary. A DC current is supplied to the rotor which creates a magnetic field. As the magnetic field sweeps around the magnetic field is cut by the the stator windings which induces a voltage in the windings. The electrons will "pile" up as the magnetic field peaks and then be reduced to zero and swing to the opposite direction continously. It gets much more complicated with the load control voltage control etc. but this is the gist of it. It may seem like a zero sum game, but consider a sawzall vs. a band saw. A sawzall goes back and forth returning back to its original position (AC), but it still does work (cutting the wood). A bandsaw goes in the same direction continuously (DC) and cuts the wood. They both do the same work but achieve it in different ways.
nice explanation
 
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