Is this real?

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http://www.bikerumor.com/2012/02/24/magnic-light-a-dynamo-that-functions-free-of-components
Anyone seen this?
There are cyclist forums full of speculation as to how this might work or might be a scam.
I'd be interested in the opinions of the learned people here.

Four legs good, two legs bad, three legs stable.

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Yes it's real but it's not better than a well designed dynamo...

If you have a low loss dynamo and a LED light you just consume less power. Thus you take less power from the spinning wheel.

Also this thing takes power from the wheel in some sort. The question you should ask is: what is the conversion efficiency from motion (spinning wheel) to light.

In the video the 'compare' a dynamo with their system. And you can immediately see some flaws: different type of wheels/bike, old dynamo, different type of light. It's not a fair comparison. It's not even a comparison at all...

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Quote:
Also this thing takes power from the wheel in some sort.

Yes, I knew that. I wasn't for one moment suggesting that they had discovered the secrect of perpetual motion or free power!
The question I was asking is if it does work, then how? I'm not planning on buying one, or funding the project, just simple curiosity.

Four legs good, two legs bad, three legs stable.

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http://en.wikipedia.org/wiki/Edd...

It's can be used as a braking force. So you can do the reverse. Just like a dynamo being the reverse of a electrical motor.

I've no idea how it is designed. I'm happy with understanding the principles.

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I agree with jan_dc. Efficient LEDs are dramatic compared to the old incandescent torch bulb. 4 AA batteries and my LED cycle light works very well.

I am sure there is room for improvement in efficiency. In which case you get more lumens, a better beam, longer battery life.

I am very sceptical about getting 150 lumens from that video. It looks more like 15 lumens.

Yes. I am sure that you can generate some sort of power with moving a conductor through a magnetic field. There are many home made experiments with coils and Earth's magnetic field lighting a tiny bulb. They generally 'cut' across the lines of field. Any magnetic field set up by this device is in the same plane (I guess).

No. I won't put any money into it. I will carry on with AA batteries.

At the end of the day, with a cycle power has to come from the human leg. Well designed bikes convert human power very efficiently. I believe 80%-90%. AA cells are pretty good too. I doubt that this device could ever be that efficient. OTOH, where would the inefficiency be dissipated?

David.

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jan_dc wrote:
http://en.wikipedia.org/wiki/Edd...

It's can be used as a braking force. So you can do the reverse. Just like a dynamo being the reverse of a electrical motor.

I've no idea how it is designed. I'm happy with understanding the principles.


I'm not so sure. Yes, I understand the principle, but I don't believe you could extract enough power.
As far as I understand things, eddy currents induced in the alumin(i)um rim produce a magnetic field that then induces a current in a coil. I tried a simple experiment(alumin(i)um/stack of rare earth magnets/coil/oscilloscope) and wasn't able to detect anything.
Actualy, that's not true, one can see the aluminium moving in response the the movement of the magnets(although Al is paramagnetic, anyway). what I couldn't observe was any vertical deflection of the scope trace.

Four legs good, two legs bad, three legs stable.

Last Edited: Wed. Mar 21, 2012 - 11:04 AM
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John_A_Brown wrote:
jan_dc wrote:
http://en.wikipedia.org/wiki/Edd...

It's can be used as a braking force. So you can do the reverse. Just like a dynamo being the reverse of a electrical motor.

I've no idea how it is designed. I'm happy with understanding the principles.


I'm not so sure. Yes, I understand the principle, but I don't believe you could extract enough power.
As far as I understand things, eddy currents induced in the alumin(i)um rim produce a magnetic field that then induces a current in a coil. I tried a simple experiment(alumin(i)um/stack of rare earth magnets/coil/oscilloscope) and wasn't able to detect anything.

Look at how alternators start. The magnetical field is generated by the electricity it produces. So I think it is possible with eddy currents too. Efficiency is an other matter...

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jan_dc wrote:
John_A_Brown wrote:
jan_dc wrote:
http://en.wikipedia.org/wiki/Edd...

It's can be used as a braking force. So you can do the reverse. Just like a dynamo being the reverse of a electrical motor.

I've no idea how it is designed. I'm happy with understanding the principles.


I'm not so sure. Yes, I understand the principle, but I don't believe you could extract enough power.
As far as I understand things, eddy currents induced in the alumin(i)um rim produce a magnetic field that then induces a current in a coil. I tried a simple experiment(alumin(i)um/stack of rare earth magnets/coil/oscilloscope) and wasn't able to detect anything.

Look at how alternators start. The magnetical field is generated by the electricity it produces. So I think it is possible with eddy currents too. Efficiency is an other matter...

Not that it's relevant, but don't alternators rely on batteries to "start"?

Four legs good, two legs bad, three legs stable.

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John_A_Brown wrote:
jan_dc wrote:
John_A_Brown wrote:
jan_dc wrote:
http://en.wikipedia.org/wiki/Edd...

It's can be used as a braking force. So you can do the reverse. Just like a dynamo being the reverse of a electrical motor.

I've no idea how it is designed. I'm happy with understanding the principles.


I'm not so sure. Yes, I understand the principle, but I don't believe you could extract enough power.
As far as I understand things, eddy currents induced in the alumin(i)um rim produce a magnetic field that then induces a current in a coil. I tried a simple experiment(alumin(i)um/stack of rare earth magnets/coil/oscilloscope) and wasn't able to detect anything.

Look at how alternators start. The magnetical field is generated by the electricity it produces. So I think it is possible with eddy currents too. Efficiency is an other matter...

Not that it's relevant, but don't alternators rely on batteries to "start"?

No, they rely on the left over magnetism. You can 'magnetise' iron by putting it near a magnetic field. So the core of the coil is a bit magnetic which is enough to have a current generated, this current is then used to create a stronger magnetic field. The generated current rises and so on.

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Quote:
Look at how alternators start. The magnetical field is generated by the electricity it produces.

Quote:
No, they rely on the left over magnetism.

Make your mind up!

Four legs good, two legs bad, three legs stable.

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Thanks for the decent explanation George. My knowledge of the subject is really far and I keep missing the differences between dynamo and generator. I thought that a dynamo was with permanent magnets.

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John_A_Brown wrote:
Quote:
Look at how alternators start. The magnetical field is generated by the electricity it produces.

Quote:
No, they rely on the left over magnetism.

Make your mind up!

Ever made a piece of metal magnetic? In a sort of way you can 'charge'a piece of metal with magnetism.

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They do start up with residual magnetism.

Think about it. A regular emergency generator is just run with a shaft from a diesel engine.

David.

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And the voltage regulator modulates this field current to regulate the output voltage.

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My (ex) emergency generator simply runs from a tractor PTO. There is no means of field excitation. i.e. no connection to the tractor battery.

You start it up on no load. Once 240V 3PH is present, you switch on the load. It will supply about 24 kVA with barely a murmur as 3PH motors stop and start.

I have never looked inside those little Honda site generators. I presume they work in a similar fashion.

Of course it may well be that these generators have some permanent magnets, just to get their field excitation going.

David.

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Old fashion (car) dc generator starts with residual magnetism (remanence). Alternator starts also without external field current but it needs quite high rpm.
Normally charge indicator light helps (grounded trough field), but surely alternator start charging without light bulb and so without external current.

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The current harnessed through an imperfect irregular conductor like an unmodified wheel through a strong field say from a neodymium magnet in the light case, should be strong enough to charge a small bank of capacitors to power efficient high-power LED's housed in good reflectors. Not a 10W load but a few good LEDs certainly.

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jan_dc wrote:
John_A_Brown wrote:
Quote:
Look at how alternators start. The magnetical field is generated by the electricity it produces.

Quote:
No, they rely on the left over magnetism.

Make your mind up!

Ever made a piece of metal magnetic? In a sort of way you can 'charge'a piece of metal with magnetism.


I wasn't disputing that. I'm 59 years old and started playing with electro-magnets about 50 years ago. I once built a primitive wire recorder when I was a kid, so I fully understand that some metals can be magnetised.
I'm not a complete idiot.
I was merely pointing out that your two statements were contradictory.

I also have no problem with the idea that David's alternator uses residual magnetism to "bootstrap" itself, although automotive alternators, according to my reading, are more likely to use the residual magnetism generated power to "open" the voltage regulator, at which time the battery will power the field windings.

All I wanted was opinions on whether this thing was actually a practical possibility.

Four legs good, two legs bad, three legs stable.

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I share your interest. I would like to see / try the device for myself.

I was never very good with EMT (electro magnetic theory) at college. I find it difficult to see an aluminium wheel rim moving in the correct spatial plane for 'cutting' the magnetic field.

However the spokes may create the relevant current circuit.

Does it work with aluminium rims and a plastic hub / solid wheel?

David.

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John, I'm not native speaking English. So I do make mistakes in my English and sometimes I struggle with finding the correct words and sentence construction.

Yes, residual magnetism is used to startup some generators. Not everything in the world is high tech regulated stuff. Lots of things are plainly simple.

I don't see any contradiction in my statement. The residual magnetism comes from the coils. That way they start and can feed the coils with power so that the become MORE magnetized (and thus generate more power). So why not with Eddy currents? Sure there is something residual that can be used to increase the Eddy effect.

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For David, and anyone else who is intrigued by this, here's a link to where I came across this thing.
http://www.kickstarter.com/projects/dynamodirk/magnic-light-get-new-energy

And I share your difficulty with the whole cutting the magnetic field thing, but then again,
http://en.wikipedia.org/wiki/Homopolar_generator

Four legs good, two legs bad, three legs stable.

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@jan_dc:

Quote:
So why not with Eddy currents? Sure there is something residual that can be used to increase the Eddy effect.

I don't think that's the issue here, as we know they have permanent magnets in the generator.
Also, they state that this thing works on aluminium or magnesium rims, so it would have to work with residual paramagnetism, which, if it even exists, is likely to be a much, much weaker effect.

Four legs good, two legs bad, three legs stable.

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I watched the video and it appears a magnetic rotor is driven by the aluminum wheel. I assume the rotor drives an alternator.

If you understand how old eddy current speedometers, magnetic damping, or eddy brake systems work you will understand the concept.

A small engine generator has a rotor exciter field that is driven by rectified output from the stator. Remnant magnetism gets it started. I repaired and used one in a hybrid vehicle in the mid 80's. I changed the stator connections to parallel the windings to halve the voltage and made an exciter regulator to control charging voltage and current.

It all starts with a mental vision.

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Quote:
I watched the video and it appears a magnetic rotor is driven by the aluminum wheel. I assume the rotor drives an alternator.

Interesting, that is one of the ideas put forward in the cycling forums, and I can see how that work.
The official explanations, however, don't mention any moving parts(or maybe I didn't read it carefully enough).
I will do an experiment later with a couple of magnets free to rotate on a shaft, and my trusty aluminium bike wheel.

Four legs good, two legs bad, three legs stable.

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John_A_Brown wrote:
@jan_dc:
Quote:
So why not with Eddy currents? Sure there is something residual that can be used to increase the Eddy effect.

I don't think that's the issue here, as we know they have permanent magnets in the generator.
Also, they state that this thing works on aluminium or magnesium rims, so it would have to work with residual paramagnetism, which, if it even exists, is likely to be a much, much weaker effect.

I must admit I didn't read the aluminum part. But even then if a current flows in aluminium it generates a magnetic field though aluminum is not magnetic by itself.

Questions I have:
How do they increase the Eddy effect, regardless of the material used?
Is there a 'base' Eddy effect in aluminium?
What is the minimal Eddy effect needed to be able to build it up?

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It is about a conductor cutting magnetic lines of force.

I am old enough to have motor and power lab experience as part of my EE degree. Yet young enough to learn computer programming.

Too bad what is not understood due to down sizing our education system, now appears as magic.

It all starts with a mental vision.

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KitCarlson wrote:
It is about a conductor cutting magnetic lines of force.

I am old enough to have motor and power lab experience as part of my EE degree. Yet young enough to learn computer programming.

Too bad what is not understood due to down sizing our education system, now appears as magic.


Well I've been back and re-read all the posts in this thread, and I can't see where anyone suggested it was magic.

Four legs good, two legs bad, three legs stable.

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Surely anyone who recognises this secret sign:

and understands how it can easily be changed to a two finger salute directed towards a teacher is old enough to not have been involved in a "dumbed down" education system? :?

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They don't still teach this?

Next thing you'll tell me that they don't teach Maxwell's Equations.

Smiley

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Wait!

So it will only work if the bike is moving backwards!

JC

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Smiley,

I don't think they even teach ohm's Law nowadays.

Judging by some of the simple electronics questions here, there is something missing in the education system.

I do not expect a 12 year old hobbyist to understand circuits. I do expect a University student to have a reasonable knowledge. After all, she presumably took Maths and/or Science/Physics at school before starting on a Computer Science course.

Mind you, my eyes used to glaze over during EMT lectures.

David.

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If the housing contains a magnet, moving a metal rim near it will generate eddy currents, but it will generate those currents in the metal of the rim, not in the magnet. Unless you somehow magnetize the rim and move that magnet past the coil, I simply don't see how you can generate any current flow in a location where it can be passed to the LEDs.

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10 watts of electrical energy is exactly the same as 10 watts of heat generated by friction. If a dude is humping out 100 watts to haul himself down the road, and he flips on that 10W generator, he will feel the work load in his thighs increase.

Imagecraft compiler user

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bobgardner wrote:
10 watts of electrical energy is exactly the same as 10 watts of heat generated by friction. If a dude is humping out 100 watts to haul himself down the road, and he flips on that 10W generator, he will feel the work load in his thighs increase.

Why does everybody keep talking as though it has been suggested that this is some sort of free energy?
I started this thread, and I am totally aware that you will have to pedal harder to make the LED light.

Anyhow, I found a small ball race and stuck 4 neodymium(spelling?) magnets to the outer journal and stuck a 8mm bolt through the centre hole. Holding this very close to my spinning cycle wheel I discovered two things:
1) My wheel rims seem to be made in two parts, part is steel and part is aluminium.
2) I could not get the contraption to revolve. Not at all.
I tried this with all norths outwards, and then north south alternating.

The only other noticeable effect was that a lot of paperwork fell off the fridge door, as that's where the magnets generally live.

I am leaning heavily towards thinking that this is a scam, but I hope I am wrong.

Four legs good, two legs bad, three legs stable.

Last Edited: Thu. Mar 22, 2012 - 07:58 PM
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"What do they teach in these schools nowdays?" -- C. S. Lewis "The Lion, The Witch and The Wardrobe"

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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Giorgos_K wrote:
Chris, this is exactly how the inductive pickups (or reluctors) crankshaft/camshaft position sensors work. Well, not exactly because they can only sense the proximity/movement of ferromagnetic materials (and not of aluminium, for example). But the amounts of power they produce is nowhere near the amounts needed to power such heavy loads as these described above. They can only drive amplifier stage inputs...

-George

Or, of course, electric guitar pickups.

Four legs good, two legs bad, three legs stable.

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Chris-Mouse wrote:
If the housing contains a magnet, moving a metal rim near it will generate eddy currents, but it will generate those currents in the metal of the rim, not in the magnet. Unless you somehow magnetize the rim and move that magnet past the coil, I simply don't see how you can generate any current flow in a location where it can be passed to the LEDs.

Yes, but the idea is(I think) that those eddy currents generate their own magnetic field, and that can induce a current in a nearby coil. Except that to my mind, the section of the rim near the magnet would be the part with the eddy currents, and thus the magnetic field, but would this field be moving with respect to the coil?

Four legs good, two legs bad, three legs stable.

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Those inductive pickups work on magnetic materials, not conductive materials. Bringing magnetic material into a magnetic field will reduce the reluctance of the magnetic circuit, and thus increase the magnetic field strength. The changes in the magnetic field induce voltages in the sensor coil, which are then detected. This has nothing to do with eddy currents. It also won't work with nonmagnetic materials, like aluminum wheel rims.
They have almost certainly left out most of the technical information in the Kickstarter video. Without the technical details, I simply can't see how they can arrange a system that can generate anything more than trivial amounts of electricity on the same side of that system as the magnet.
As far as I can see, either the magnet has to be mounted on the wheel, or else the electricity is generated on the wheel. The only other possibilities I see are that there's some sort of internal mechanical arrangement that's almost certainly going to be less efficient than an old fashioned dynamo.

That said, I'd be happy to be proven wrong. I do hundred kilometer bicycle day trips, and I'd love to have a low maintenance lighting system like that.

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Quote:
Those inductive pickups work on magnetic materials, not conductive materials.

That has been said already.

Quote:
Chris, this is exactly how the inductive pickups (or reluctors) crankshaft/camshaft position sensors work. Well, not exactly because they can only sense the proximity/movement of ferromagnetic materials

I guess we will just have to wait and see.

Four legs good, two legs bad, three legs stable.

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I say this is about as plausible as the other thread with the guy flying with wings...

JC