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generating electricity? Answered

im am a novice at electics,  i think that a coil of wire through a magnetic field will generate a charge,  Yes/no?  if so would a number of coils passing through one magnetic field be more or less efficient than 1 coil passing through many magnetic feilds?



6 years ago

If you mean that you get more voltage or more current with more wires,
You are right !

But each wire still generates the same as a single wire.
When wires are combined you get more output in proportion to the wires.

Spinning wires through a magnetic field or
spinning magnet flux through stationary wieres
does generates electricity..


Jack A Lopez

6 years ago

Please allow me to tell you the story of how electrical generators work, the story that was told unto me by my ancestors, and also my physics textbooks, and also Wikipedia.

The principle at work in a generator is something called Faraday's Law,
and it is easiest to understand in the special case of a coil of wire, with N turns, and a quantity of magnetic flux Phi(t) enclosed by that coil of wire. Note that Phi(t), the flux enclosed by the coil, is changing with time.

Also for now, assume that the coil of wire is open, with only a voltmeter wired across it.  So I can measure the potential V(t) across the coil, but no significant current flows in the coil.

What Faraday's law says is that a potential, a voltage, V(t) will be induced in the coil when there is changing magnetic flux in the coil, and the formula for this is:

V(t) = N*(dPhi/dt)

So you get a voltage that is proportional to the rate of change of magnetic flux, and also proportional to the number of turns in the coil.

First Voltage, then Current

This is the way generator action is usually though of happening.  First you get this induced voltage via Faraday's Law, V(t) = N*(dPhi/dt).  Then if you've got a load connected to the coil, the voltage will cause current to flow.  The amount of current that flows depends on the resistance in the load connected across the coil, and the resistance in the coil itself. That is:
I(t) = V(t)/(Rcoil + Rload)

How to get more voltage?

That formula from Faraday's Law suggests three ways to get more voltage. These are: (1) use more turns in the coil; (2) use stronger magnets; (3) make the magnets move faster past the coil

What size wire? What size coil?

So if all I want to do is create voltage, the best type of coil for this one made from very fine wire, with a huge number of turns.  A coil like this will have large resistance Rcoil to current flow, but I don't care about that because I am not going to be drawing any current from the coil, and also no power as well.

Supposing I actually wanted to build a useful generator, one that I could actually draw current, and power, from.  Then I would have to do some thinking about the relative sizes of Rcoil and Rload.  Since those are in series, they share the same current I.  There is I*Rcoil of power being wasted just heating the coil, and there is I*Rload of power where I want it to be, in my load.  So just from that simple model, the efficiency is Rload/(Rcoil+Rload).  

So if I want the generator to be somewhat efficient, that means making Rcoil smaller than Rload.  But to make a coil with less resistance requires fatter wire and fewer turns, and that is sort of moving away from the kind of coil I had when all I needed was voltage.


6 years ago

Depends on whet your trying to accomplish. A good generator will have multiple coils and multiple magnets. Look at some of the wind turbine builds here. Some of theme are made from scratch where people wound there own coils and used there own magnets to create the generator. Here is a great one where they made there own generator.



Answer 6 years ago

Like mpilchfamily said, it's really about what you are trying to accomplish. Your question, QSDR, is confusing in that multiple coils wired together in a certain fashion is the same as one larger coil. Efficiency can't really be determined with the information you have given. If this doesn't help, try rephrasing the question.


Answer 6 years ago

hmm all valid points.. perhaps i will research coil types, ie gage of wire x amount of turns,.
(_), the question was a generalisation, i hypothesized that one method would prove to be advantagous taken into acccount the ~8 or so combinations of rotor stator arrangements (not including multiplying both conductors and fileds). could i expect to make use of a generator made with as few magnets as possible and still get competitve power gains or is maximum magnetic feild a must. best result with minimal resource.
i see how multiplying both the field and 'conductors' (thanks frollard and mpilchfamily) would yield strongly, but if one had to choose( for example coiling a wire seems a much more attainable than making magnets) .

i see now this is a 'can of worms' type thing for me to understand i will keep searching.. at the moment the power genreation was not for a specific purpose but for educational purposes only, i greatly appreciate the input and thanks for helping me to understand more.
any info on coil arrangemtns would be handy, wire gage x amount of turns. cheers.


6 years ago

A moving single conductor through a magnetic field (relatively) will cause a charge to flow through the conductor, yes.

Moving multiple conductors through that same field will induce the same charge in EACH of those wires. Now connect those wires end to end, they form a loop or coil.
Having multiple conductors (in series) = a coil with multiple windings = higher voltage, as each winding will take some of the magnetic field and use the force (of the relative movement) to generate more voltage.

Using more coils one after another has many effects, notably increasing the effective frequency of a generator, or input switching requirement for a motor. It's often easier to physically fit more small coils than it is to fit fewer larger coils.