So I'd lke to make this programable; therefore, in lieu of a permanent magnet and bringing it closer to the disk to increase the resistance I could use an electromagnet and increase the magnetic field?
On Mon, Mar 29, 2010 at 11:39 AM, David C. Kerber <[1][email protected]> wrote: Just attach a disk of some conductive material to the axle of the thing you want to brake, and mount a strong permanent magnet so that it's near but not touching the flat surface of the disk. I think a C-shaped magnet with the opening just big enough to clear the disk would work even better, but it's not required. I believe my trainer uses two magnets, one on each side of the disk, facing each other. If you're putting any significant continuous load on it, you will need some cooling; my trainer's load box get pretty warm after I've been using it for 20 minutes or so, and it has fan blades to drive air flow through it whenever it's turning. > -----Original Message----- > From: [2][email protected] > [mailto:[3][email protected]] On Behalf Of Rob Butts > Sent: Monday, March 29, 2010 11:15 AM > To: gEDA user mailing list > Subject: Re: gEDA-user: Magnetic bike operation > > I've read about the eddy current breaks but it's still not > clear to me how to construct one. The wikipedia talks about > a rotor connected to a spinnning coil. I would think the > rotor would spin inside a coil. Then wikipedia talks about > using electromagnets and varying the breaking force by > varying the magnetic field. > > On Sun, Mar 28, 2010 at 8:03 PM, David C. Kerber < > [4][email protected]> wrote: > > > My bicycle trainer uses an eddy current brake; there are no wires > > anywhere in the load; just a ventilated disk and a magnet > that I can > > move closer or further away from the disk by turning an > adjustment dial. > > > > D > > > > > > > > > -----Original Message----- > > > From: [5][email protected] > > > [mailto:[6][email protected]] On Behalf Of Rob Butts > > > Sent: Saturday, March 27, 2010 4:29 PM > > > To: gEDA user mailing list > > > Subject: gEDA-user: Magnetic bike operation > > > > > > I'm having a debate with an ee friend about how the magnetic > > > resistance works on an excersice bike. > > > > > > It occurred to me this would be the best place to solve it. > > > > > > Does anyone know if it is simply an electro-magnet close > to a metal > > > wheel where the stronger the magnetic field the stronger the > > > resistance? Or is it alternating magnets in a flywheel type > > > configuration with a toriodal coil surrounding the flywheel and a > > > variable resistance in the coil circuit resists the > induced current > > > providing the resistance to user who would be spinning > the flywheel? > > > (Sorry if I didn't describe that well). > > > > > > Or is it something completely different? > > > > > > Thanks > > > > > > > > > _______________________________________________ > > geda-user mailing list > > [7][email protected] > > [8]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > > _______________________________________________ geda-user mailing list [9][email protected] [10]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user References 1. mailto:[email protected] 2. mailto:[email protected] 3. mailto:[email protected] 4. mailto:[email protected] 5. mailto:[email protected] 6. mailto:[email protected] 7. mailto:[email protected] 8. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user 9. mailto:[email protected] 10. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
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