Output of Generator if Field is AC

Even more "clarification":

The BSA C15 (I had one) had an alternator with a PM rotor (mounted directly to the crankshaft), and a wound stator - so no brushes.

That's nice. However, how does one apply single phase AC power to this permanent magnet alternator? HiTek was asking for more information from the AP and did a nice job of showing why it is needed. Instead you decide to ignore the little bit of information we do have about the question by providing information about an alternator that does not apply. Should we now discuss the flickering of your headlight from this unregulated supply?

I was just addressing this statement:

"An alternator,by contrast,only carries the field current through the brushes,which is relatively small compared to the load current,and the brushes do not commutate."

To smooth your ruffled sensibilities I've marked myself OT.

That configuration is typical for motorcycles,lawn mowers,etc.,but has limited output power,because the requirements are low,regulation is not required,and weight and cost is at a premium.

It is simply a glorified magneto,which has been used for years to provide spark ignition.

The simplest means of generating power,in my opinion, is the trailing conductor of the space shuttle:

Simply a long wire ,25 miles or more, that produces power as the shuttle orbits the Earth.

When first deployed,it produced such a surge of power that it broke,and went off into space like a crazy slinky.

Later, after redesigning the conductor, they discovered that by pumping power into it they could develop thrust,increasing altitude,and by extracting power from it,it would reduce altitude.

No need to carry chemical fuel to regulate orbital speed.

This technology is used in a lot of newer satelittes to extend their useful life.

"The simplest means of generating power,in my opinion, is the trailing conductor of the space shuttle:

Simply a long wire ,25 miles or more, that produces power as the shuttle orbits the Earth.

When first deployed,it produced such a surge of power that it broke,and went off into space like a crazy slinky.

Later, after redesigning the conductor, they discovered that by pumping power into it they could develop thrust,increasing altitude,and by extracting power from it,it would reduce altitude.

No need to carry chemical fuel to regulate orbital speed.

This technology is used in a lot of newer satelittes to extend their useful life."

I'd say something stupid like "you're pulling my leg, right?", but I know you better than that.

This is fascinating, and I had no idea. Now THAT is cool applied science! Is this the ion stream engine application I've been seeing mentioned again in the press, recently?

I knew a kid in the California Science Fair Competition (middle-school, I won, but if his had worked, he'd have eaten my lunch) who tried to measure the thrust produced by one of those little rotating "ion motor in a glass bubble" novelty devices, in hopes of being able to find a way to scale it up to a usable ion thrust motor for space vehicles. THAT obviously didn't work, and he couldn't come up with a reliable and demonstrable method to measure thrust, nor even "prove" it provided thrust, but it sounds like this trailing wire antenna is the ultimately simpler version, and that, because of sheer size (and no doubt THAT is helped by available materials, probably NOT available, even to NASA 50 years ago), it works in a much simpler, and more efficient, fashion than we could even have dreamed of.

But we were ony 6th graders, so what more do you want?

Could've measured the thrust (approx) by sacrificing one, smashng it to get the rotor out to weigh it, then timing the acceleration when taken from dark to light.

Maybe, but did you ever look at one? The rotor can't weigh a tenth of an oz, and is only about 1 inch diameter. Or maybe 1 1/4 inch tip to tip. None of us had access to equipment sensitive enough to get any accuracy with that, let alone a tach that would let us time acceleration that close. Then realize that to convince anyone it could scale, either by multiplying rotors, or increasing rotor size, with the attendant increase in the absolute magnitude of included errors due to the test gear available, well, the error magnitudes would be astronomical.

Nah, he tried all that. But we just didn't have what it took.

My project used a hotdog as a resistor, plugged directly into an AC powered extension cord (with a couple of nifty looking forks I made, in nice lucite enclosures) to demonstrate resistive cooking. I varied the voltage through a variac I had found in the junk, and made several measurements of time, temp, thoroughness of cooking (By taste test. Even the judges taste tested them. Not bad, but a little funky tasting, I thought. But then, I always preferred mine cooked on a stick over an open fire.)

Nonetheless, it WAS a subjective data collection process, and I would severely downgrade it on any project I was judging today. Even a middle-schooler's project, given how good science fair students in Virginia, in the USA, are today.

But it won the competition. I've never thought THAT was my finest Science Fair hour.

Here is a link that gives some information on it.

A lot of detailed information is no longer in the public domain.FWIW!

Link? Not there. Didn't come over. Thanks. I'll be watching.

Google "space shuttle tether incident".Then sift through till you find it.Can't seem to get a link to work today for some reason.

The power produced varies with the magnetic filed strength and the rate that the magnetic force lines are cut by the conductor.
The shuttle is traveling at thousands of miles per hour through the Earth's magnetic field so that is a lot of potential power.
This is not a free lunch for satellites,however,as they must use solar power and fuel cells to adjust their altitude,but it will not run out like chemical fuels.
Kinda make you wonder if they can put a large coil array in orbit,and beam the power back to earth via microwave.
I realize that it is very expensive to put every ounce into orbit,but when we settle the moon, it would be much easier to build and deploy from there.
Add to that the plentiful Helium 3 on the lunar surface,and it sounds like the next Lunar Energy Export Company,INC (c)(TM) will be on the moon.

OPEC will be replaced by LEECOINC(c)(TM).

The craters of the moon will be domed over,glowing,and populated,and the moon will look like it is coated in diamonds with all of the industry running 24/7.

The domes will be built by self replicating nanobots,using the lunar soil as building material,one molecule at the time,giving the domes a crystalline appearance.

The moon of our ancestors will no longer be seen as it was for billions of years.

The sand in my hourglass of life will probably run out before it comes to pass,but I can see it clearly nonetheless.

A lot of detailed information about the tether incident is no longer in the public domain.FWIW!

And in typical mankind fashion there will be war on the moon and they will send rockets at each other. We will be able to watch from any place on earth the

"And the rocket's red glare, the bombs bursting in air,

Gave proof through the night that our flag was still there"

'... but when we settle the moon, it would be much easier to build and deploy from there....'

The Moon is likely too distant to make use of the Earth's magnetosphere and although there have been discoveries of small areas protected by weak magnetic fields on the moon, it might be difficult to make use of the patchy weak magnetic fields there.

....or perhaps I misunderstood and you meant build on the moon, and deploy in a closer Earth orbit.

.

So, here is a related question: do you think this would work in a geosynchronous orbit? If you rotate a magnet with the axis of rotation aligned the axis through which it is magnetized, the magnetic field is not supposed to rotate, which would suggest it would work in a geosynchronous orbit....but if that is the case, it should work here on the ground as well....

I might be missing something, but if the body to which the tether is attached is in GeoSync orbit, does that not mean that it stays in relative stability to the earth's magnetic fields then, and in turn, in stability relative the lines of flux?

And if all that is so, then the tether won't "cut" the lines of flux (no relative motion) so there should be no power generated.

Or is my understanding of the tech flawed.

If not, perhaps a bank of Hall Effect Sensors could be deployed in place of the tether, though I don't think the Hall sensors can act as power sources. Rather as very small signal power sinks, no?

Now I remember, and I didn't even have to Google it. I just didn't make any connection, since I didn't have time to read the whole article I saw. But it does make sense.

Thanks.

And as far as the Moon Industries go; Kris? KrisDel Industries is needed here! Kris! Where are you?

Lokeshloki is that you?

Non-Sinisoidal Power Supply

Amplifiers with AC Biasing Voltage

Oscillator With AC Power