[sdiy] OT: Generator?

[patchell]

    This is a well know effect.  Diesel Locomotives use this very principle
to slow the train down going down hills.  They turn the traction motors into
generators and disipate the power in resistor grids.

    I will try to give a "coherent" hand waving explaination of why this
happens.  When you have no load on the generator, no current is flowing in
the windings.  When you put a load on the geneator, you now have current
flowing in the winding.  Current flowing through any conductor sets up a
magnetic field.  It just so happens that the magnetic field caused by the
current flowing through the wires opposes the magnetic field of the field
magnets.

    Another way to look at it is from an energy stand point.  When you have
a load on the geneator, work is being done on the load.  The more load, the
more work being done.  The energy that you are putting into the system is
the crank, so this means that the more work is being done on the load, the
more work you are going to have do cranking your crank, which means that it
is going to get harder to crank.....somehow that sounds bad....oh well.

Mitchell Hudson wrote:

>     I got in an argument with a guy the other day about genertors. He
> says that if you are turning the crank on your generator and there is NO
> load connected to it it will get harder to turn when you connect a load
> to it. For example you have a generator connected to a radio the radio
> is off and you are turning the crank; you turn the radio on and it takes
> mre force to turn the handle.
>     After talking with a few people I was convinced that this was true
> but no one could explain it.
>
> --M

--
 -Jim
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