Magnic Light
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Yiping Lin
Mar 10, 2012, 9:06:02 PM3/10/12
to ran...@googlegroups.com
Hello:
Magnic Light at KickStarter
When I first saw this in BikeRumor site, I have been thinking that it might be useful in randonneuring and commuting. I also talked to some of my friends and asked whether they'd be interested.
Last Friday when I went to Taipei Cycle, I was very surprised to see the inventor in person. I took two short videos of his demo (on the bike and the principle behind-- see the strong magnet does not fall acceleratedly along the aluminum tube).
After seeing him in person, I decided to become a backer. There are still some improvements (stand light, steady light). I plan to use this set assisted with the helmet lights (and maybe additional low-power front light) on my road bike. Then move my Schmidt SONdelux to my new 650B project.
Yiping
PS: The key priciples are Lenz's law and Eddy Current.
Magnic Light at KickStarter
When I first saw this in BikeRumor site, I have been thinking that it might be useful in randonneuring and commuting. I also talked to some of my friends and asked whether they'd be interested.
Last Friday when I went to Taipei Cycle, I was very surprised to see the inventor in person. I took two short videos of his demo (on the bike and the principle behind-- see the strong magnet does not fall acceleratedly along the aluminum tube).
After seeing him in person, I decided to become a backer. There are still some improvements (stand light, steady light). I plan to use this set assisted with the helmet lights (and maybe additional low-power front light) on my road bike. Then move my Schmidt SONdelux to my new 650B project.
Yiping
PS: The key priciples are Lenz's law and Eddy Current.
Ken Freeman
Mar 11, 2012, 7:09:27 AM3/11/12
to Yiping Lin, ran...@googlegroups.com
Discussions on numerous other groups, involving people who do understand Lenz's Law and eddy currents, have not come up with a reasonable explanation for these lights. Your faith is heartening, as is the fact that you saw them shine, but your (identical?) videos only portray a pair of lights shining. Was one of them supposed to be an explanation?> --
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William D. Volk
Mar 11, 2012, 11:30:32 PM3/11/12
to Ken Freeman, William D. Volk, Yiping Lin, ran...@googlegroups.com
I think the explanation of a rotating disc inside the unit with magnets in the disc, inside the unit ... is feasible and could work.
See prior post for details.
William D. Volk
BA Physics, PENN
Masters, UNH :-)
Ken Freeman
Mar 12, 2012, 12:18:46 AM3/12/12
to William D. Volk, Yiping Lin, ran...@googlegroups.com
Not sure what post you're referring to, exactly. This product, if you look at it from a systems point of view, needs very high throughput and efficiency. In most if not all electrical machines small gaps in any magnetic circuits are necessary. But just to look at one interface, the magnet to bicycle rim gap is at least 5 mm. This is vastly larger than the 0.5 mm gap more usually found in electric machines.
William D. Volk
Mar 12, 2012, 9:05:05 AM3/12/12
to Ken Freeman, Yiping Lin, randon@googlegroups.com subscribers
My prior post:
'
We've had a lot of discussions about it on the various forms.
What we've come to is a possible conclusion on how it works. (Disclaimer, I do have a degree in Physics but I'm not currently in that profession).
Eddy current effects will induce a braking force on rotating metallic discs with a magnet placed close to the spinning surface. I've played with this when I was at University and the effect is used in some dynamometers to measure the torque of an engine.
What we think MAY be going on in this device is a disc with magnets along it's edge in the device oriented in the horizontal plane is spun as a result of the Eddy Current effect in the rim. A coil opposite from the rim generates electricity from the poles of the magnets passing it.
http://www.bicycleman.com/recumbent-exercise-bikes/magnetic-resistance-recumbent.htm
What we've come to is a possible conclusion on how it works. (Disclaimer, I do have a degree in Physics but I'm not currently in that profession).
Eddy current effects will induce a braking force on rotating metallic discs with a magnet placed close to the spinning surface. I've played with this when I was at University and the effect is used in some dynamometers to measure the torque of an engine.
What we think MAY be going on in this device is a disc with magnets along it's edge in the device oriented in the horizontal plane is spun as a result of the Eddy Current effect in the rim. A coil opposite from the rim generates electricity from the poles of the magnets passing it.
Eddy Currents can produce sufficient force to rotate a disc with embedded (probabily rare-earth) magnets along it's circumference. Eddy current dynamometer's are used to measure large amounts of power. Some stationary exercise bikes may be using this as well.
If you have a powerful magnet, try holding it close to the rim on a spinning bicycle wheel.
Yep, the "The XTerra Fitness SB 540r Indoor Stationary Magnetic Recumbent Exercise Fitness Bike" uses this:
What I don't know is how much power can be extracted on the other side, with a coil close to the spinning wheel with magnets ... but that technique is used with some wind turbines and hub motors (abet with a toroidal winding in hub motors, a semi-circle version of that is possible here ... could provide more wattage).
Example of a 1000w design: http://www.make-energy.info/1000-watt-wind-turbine/
William D. Volk
Ken Freeman
Apr 4, 2012, 8:28:29 PM4/4/12
to randon
William, you're saying that there are two disks. One is actually the
rim, and another is the generator disk. The generator disk turns to
generate electricity. Its rim is studded with small powerful magnets,
I think the inventor's lit said neodymium magnets. The eddy current
braking effect of the magnetic field on the rim creates a force in the
rim. This force opposes the motion of the wheel, extracting energy
from the wheel. If we hypothesize that this braking action applies a
force to the magnets as well, the generator disk could be made to
turn, running a dynamo and lighting an LED.
The part that I'm not clear on is the hypothesis that the generation
of eddy current in a moving object and braking it applies force to the
source of the magnetic field. I can't think of any force law that
would create this force, at least I'm not familiar with one. This is
where I'm afraid this theory of operation breaks down.
I totally agree that you can do an awful lot of braking work with eddy
currents. I'd never heard or been taught in a physics or EE class
that a related force is applied to the magnet.
On Mar 12, 9:05 am, "William D. Volk" <william.v...@gmail.com> wrote:
> My prior post:
> '
> We've had a lot of discussions about it on the various forms.
>
> What we've come to is a possible conclusion on how it works. (Disclaimer, I do have a degree in Physics but I'm not currently in that profession).
>
> Eddy current effects will induce a braking force on rotating metallic discs with a magnet placed close to the spinning surface. I've played with this when I was at University and the effect is used in some dynamometers to measure the torque of an engine.
>
> What we think MAY be going on in this device is a disc with magnets along it's edge in the device oriented in the horizontal plane is spun as a result of the Eddy Current effect in the rim. A coil opposite from the rim generates electricity from the poles of the magnets passing it.
>
> Eddy Currents can produce sufficient force to rotate a disc with embedded (probabily rare-earth) magnets along it's circumference. Eddy current dynamometer's are used to measure large amounts of power. Some stationary exercise bikes may be using this as well.
>
> If you have a powerful magnet, try holding it close to the rim on a spinning bicycle wheel.
>
> Yep, the "The XTerra Fitness SB 540r Indoor Stationary Magnetic Recumbent Exercise Fitness Bike" uses this:
>
> http://www.bicycleman.com/recumbent-exercise-bikes/magnetic-resistanc...
>
> > --
> > Sent from Gmail Mobile- Hide quoted text -
>
> - Show quoted text -
rim, and another is the generator disk. The generator disk turns to
generate electricity. Its rim is studded with small powerful magnets,
I think the inventor's lit said neodymium magnets. The eddy current
braking effect of the magnetic field on the rim creates a force in the
rim. This force opposes the motion of the wheel, extracting energy
from the wheel. If we hypothesize that this braking action applies a
force to the magnets as well, the generator disk could be made to
turn, running a dynamo and lighting an LED.
The part that I'm not clear on is the hypothesis that the generation
of eddy current in a moving object and braking it applies force to the
source of the magnetic field. I can't think of any force law that
would create this force, at least I'm not familiar with one. This is
where I'm afraid this theory of operation breaks down.
I totally agree that you can do an awful lot of braking work with eddy
currents. I'd never heard or been taught in a physics or EE class
that a related force is applied to the magnet.
On Mar 12, 9:05 am, "William D. Volk" <william.v...@gmail.com> wrote:
> My prior post:
> '
> We've had a lot of discussions about it on the various forms.
>
> What we've come to is a possible conclusion on how it works. (Disclaimer, I do have a degree in Physics but I'm not currently in that profession).
>
> Eddy current effects will induce a braking force on rotating metallic discs with a magnet placed close to the spinning surface. I've played with this when I was at University and the effect is used in some dynamometers to measure the torque of an engine.
>
> What we think MAY be going on in this device is a disc with magnets along it's edge in the device oriented in the horizontal plane is spun as a result of the Eddy Current effect in the rim. A coil opposite from the rim generates electricity from the poles of the magnets passing it.
>
> Eddy Currents can produce sufficient force to rotate a disc with embedded (probabily rare-earth) magnets along it's circumference. Eddy current dynamometer's are used to measure large amounts of power. Some stationary exercise bikes may be using this as well.
>
> If you have a powerful magnet, try holding it close to the rim on a spinning bicycle wheel.
>
> Yep, the "The XTerra Fitness SB 540r Indoor Stationary Magnetic Recumbent Exercise Fitness Bike" uses this:
>
>
> What I don't know is how much power can be extracted on the other side, with a coil close to the spinning wheel with magnets ... but that technique is used with some wind turbines and hub motors (abet with a toroidal winding in hub motors, a semi-circle version of that is possible here ... could provide more wattage).
>
> Example of a 1000w design:http://www.make-energy.info/1000-watt-wind-turbine/
>
> William D. Volk
>
> On Mar 11, 2012, at 9:18 PM, Ken Freeman wrote:
>
>
>
> > Not sure what post you're referring to, exactly. This product, if you look at it from a systems point of view, needs very high throughput and efficiency. In most if not all electrical machines small gaps in any magnetic circuits are necessary. But just to look at one interface, the magnet to bicycle rim gap is at least 5 mm. This is vastly larger than the 0.5 mm gap more usually found in electric machines.
>
> What I don't know is how much power can be extracted on the other side, with a coil close to the spinning wheel with magnets ... but that technique is used with some wind turbines and hub motors (abet with a toroidal winding in hub motors, a semi-circle version of that is possible here ... could provide more wattage).
>
> Example of a 1000w design:http://www.make-energy.info/1000-watt-wind-turbine/
>
> William D. Volk
>
> On Mar 11, 2012, at 9:18 PM, Ken Freeman wrote:
>
>
>
> > Not sure what post you're referring to, exactly. This product, if you look at it from a systems point of view, needs very high throughput and efficiency. In most if not all electrical machines small gaps in any magnetic circuits are necessary. But just to look at one interface, the magnet to bicycle rim gap is at least 5 mm. This is vastly larger than the 0.5 mm gap more usually found in electric machines.
>
> > On Sunday, March 11, 2012, William D. Volk <william.v...@gmail.com> wrote:
> > > I think the explanation of a rotating disc inside the unit with magnets in the disc, inside the unit ... is feasible and could work.
> > > See prior post for details.
>
> > > William D. Volk
> > > BA Physics, PENN
> > > Masters, UNH :-)
> > > On Mar 11, 2012, at 4:09 AM, Ken Freeman wrote:
>
> > > Discussions on numerous other groups, involving people who do understand Lenz's Law and eddy currents, have not come up with a reasonable explanation for these lights. Your faith is heartening, as is the fact that you saw them shine, but your (identical?) videos only portray a pair of lights shining. Was one of them supposed to be an explanation?
>
> > > I think the explanation of a rotating disc inside the unit with magnets in the disc, inside the unit ... is feasible and could work.
> > > See prior post for details.
>
> > > William D. Volk
> > > BA Physics, PENN
> > > Masters, UNH :-)
> > > On Mar 11, 2012, at 4:09 AM, Ken Freeman wrote:
>
> > > Discussions on numerous other groups, involving people who do understand Lenz's Law and eddy currents, have not come up with a reasonable explanation for these lights. Your faith is heartening, as is the fact that you saw them shine, but your (identical?) videos only portray a pair of lights shining. Was one of them supposed to be an explanation?
>
> > > On Saturday, March 10, 2012, Yiping Lin <wilde...@gmail.com> wrote:
> > >> Hello:
>
> > >> Magnic Light at KickStarter
>
> > >> When I first saw this in BikeRumor site, I have been thinking that it might be useful in randonneuring and commuting. I also talked to some of my friends and asked whether they'd be interested.
>
> > >> Last Friday when I went to Taipei Cycle, I was very surprised to see the inventor in person. I took two short videos of his demo (on the bike and the principle behind-- see the strong magnet does not fall acceleratedly along the aluminum tube).
>
> > >> After seeing him in person, I decided to become a backer. There are still some improvements (stand light, steady light). I plan to use this set assisted with the helmet lights (and maybe additional low-power front light) on my road bike. Then move my Schmidt SONdelux to my new 650B project.
>
> > >> Yiping
> > >> PS: The key priciples are Lenz's law and Eddy Current.
>
> > >> --
> > >> You received this message because you are subscribed to the Google Groups "randon" group.
> > >> To view this discussion on the web visithttps://groups.google.com/d/msg/randon/-/VtD9wNgoCscJ.
> > >> Hello:
>
> > >> Magnic Light at KickStarter
>
> > >> When I first saw this in BikeRumor site, I have been thinking that it might be useful in randonneuring and commuting. I also talked to some of my friends and asked whether they'd be interested.
>
> > >> Last Friday when I went to Taipei Cycle, I was very surprised to see the inventor in person. I took two short videos of his demo (on the bike and the principle behind-- see the strong magnet does not fall acceleratedly along the aluminum tube).
>
> > >> After seeing him in person, I decided to become a backer. There are still some improvements (stand light, steady light). I plan to use this set assisted with the helmet lights (and maybe additional low-power front light) on my road bike. Then move my Schmidt SONdelux to my new 650B project.
>
> > >> Yiping
> > >> PS: The key priciples are Lenz's law and Eddy Current.
>
> > >> --
> > >> You received this message because you are subscribed to the Google Groups "randon" group.
> > >> To post to this group, send email to ran...@googlegroups.com.
> > >> To unsubscribe from this group, send email to randon+un...@googlegroups.com.
> > >> For more options, visit this group athttp://groups.google.com/group/randon?hl=en.
> > >> To unsubscribe from this group, send email to randon+un...@googlegroups.com.
>
> > > --
> > > Sent from Gmail Mobile
>
> > > --
> > > You received this message because you are subscribed to the Google Groups "randon" group.
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> > > To unsubscribe from this group, send email to randon+un...@googlegroups.com.
> > > For more options, visit this group athttp://groups.google.com/group/randon?hl=en.
> > > --
> > > Sent from Gmail Mobile
>
> > > --
> > > You received this message because you are subscribed to the Google Groups "randon" group.
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> > > To unsubscribe from this group, send email to randon+un...@googlegroups.com.
>
> > --
> > Sent from Gmail Mobile- Hide quoted text -
>
> - Show quoted text -
William D. Volk
Apr 4, 2012, 10:48:51 PM4/4/12
to Ken Freeman, randon
When I held a magnet near a spinning disc, I experience an equal and opposite force to the braking force on the disc (thank you Sir Isaac Newton). That's what spins the smaller disc I theorized.
The eddy current effect is used on some exercise bikes to provide resistance. That's a bit more complex, but the result of the braking force is simple Newtonian physics.
Google "eddy current braking" for more details.
Bill
Sent from my iPad
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