Really Cool Invention Brings Teens Awards (Amazing Kids-Invented What GM Couldn't)

The Salt Lake Tribune ^ | 07/06/2005 | Jessica Ravitz

[myself6]

Im done with this.

The rotor of an alternator does NOT become harder to turn as the electrical load increases. That is the ONLY point that matters when talking about this particular subject and this particular use.

It does NOT take more energy to turn the rotor of an alternator 2500 RPM when you change the electrical conditions of the load connected to its output.

[Arkie2]

I've seen those three colored lights in action on some school buses. They're confusing as all get out. Good thing that idea died!

[JAKraig]

There is no generator, they were replaced decades ago with alternators, the alternator recharges the battery and is on the same bus with the battery. When the bus voltage falls lower than the source of the highest voltage on the bus that source provides the system power. Sometimes it may be the battery but most of the time when the engine is running it is the alternator.

[norwaypinesavage]

"So... they are dumping the heat where? outside? on a hot day? Efficient?"

When you drive a car down the road (and ultimately stop), 100% of the energy in the gasoline is turned into heat and dumped into the atmosphere.

[Ranxerox]

There was NO EFFECT on the mechanical load of the engine...

Of course there is, how do you think regenerative braking works in hybrids?

[norwaypinesavage]

"It does NOT take more energy to turn the rotor of an alternator 2500 RPM when you change the electrical conditions of the load connected to its output."

It is best that you confine your comments to politics.

[myself6]

You can take your comments about "ignorance" and "stupidity" and shove them right up your Back woods Ga ASS.


You explain to me how the electrical load of the alternator makes it more difficult to turn the rotor.

[Arkie2]

I imagine the plan is to dump the heat into the car's coolant system. It's the only logical place for it to go since liquid removes heat far more efficiently than air.

[Jonx6]

"It does NOT take more energy to turn the rotor of an alternator 2500 RPM when you change the electrical conditions of the load connected to its output."

I believe that in order to increase that amperage that the alternator puts out, it increases the magnetic field strength that the conductors must pass through and that is what causes the alternator to become harder to turn.

[frgoff]

You may be right. The alternator just may simply sieze up when the cooling system draws 100 kilowatts.

[myself6]

Fine....

Then please enlighten me. ANYONE...


Under what conditions does the electrical load of an alternator make it harder to turn the rotor?

Is there some type of buildup of the magnetic flux field that works against the rotation of the rotor?


Im willing to admit I don't know something but ONLY if you can adequately explain it.

[Lee'sGhost]

More info please. What did you replace the AC with?

[Jonx6]

And I’m not talking about the permanent magnet fields; I am talking about the electrically created ones.

[Lee'sGhost]

I really think this is awesome. I mean, this is Thomas Edison type American inventiveness. I hope they focus on fusion, teleportation and faster-than-light space engines next.

[Jonx6]

I believe the PMG electricity is what is used to create the more powerful magnetic fields in the alternator.

[myself6]

Understood.

My problem here is that I don't see how the rotor becomes more difficult to turn.

I guess there could be some properties of electromagnetism that work against the rotation as the field increases do to increased current flow. That would be the ONLY way it COULD get harder to turn.

[Dad yer funny]

yup , they're on a good course

[TalonDJ]

Right, liquid transfer heat faster at the same temperature differences that gas does. Guess what temperature that coolant system is already at? Here is a hint, don't pull off the radiator cap when the car has been driven recently. You can't 'dump heat' into something that is hotter than you are.

If they want to dump heat via a liquid then need a new independent closed loop liquid heat transfer system. But no matter HOW good that transfer system is they can only get the other end down to ambient temperature.

[Mycroft Holmes]

What are the odds that somone in the know might tell the rest of us (me) what a Peltier Chip actually is?

A peliter device is a string of diodes hooked together and oriented so that all the P sides of the diodes attach to one plate and all the N sides attache to the opposite plate. The heat is transferred from one side to the other by the motion of the majority carriers in the diodes.

I have used them many times to cool laser diodes and they are terribly inefficient. Without running the numbers I would expect that you would burn more gas powering these than running a standard AC.

regards,

[norwaypinesavage]

An alternator consists of a rotating magnetic field inside several coils of wire. The rotating field generates electricity in the coils. Even at a constant RPM, if the voltage regulator senses the need for more electrical output, it increases the strength of the magnetic field. Therefore, it takes more torque to turn the field, and hence, more engine power to turn the alternator. The input energy to the alternator is directly related to the output energy that the alternator is making. More energy out requires more energy in, even at a constant RPM.