Re: gEDA-user: Magnetic bike operation

[Rob Butts <r.butts2@xxxxxxxxx>]

   Thanks guys; this is extremely helpful.

   On Mon, Mar 29, 2010 at 12:41 PM, Dave McGuire
   <[1]mcguire@xxxxxxxxxxxxx> wrote:

      Of course it'd work.  It doesn't matter where the magnetism comes
     from. ;)
              -Dave

   On Mar 29, 2010, at 12:35 PM, David C. Kerber wrote:

     I would think that would work.  IIRC from my college days, higher
     conductivity in the disk gives you stronger braking, so copper would
     be ideal, but most people's budgets call for either aluminum or
     steel.  Of course steel could handle higher temperatures, so you
     wouldn't need as much cooling...
     D

     -----Original Message-----
     From: [2]geda-user-bounces@xxxxxxxxxxxxxx
     [mailto:[3]geda-user-bounces@xxxxxxxxxxxxxx] On Behalf Of Rob Butts
     Sent: Monday, March 29, 2010 12:23 PM
     To: gEDA user mailing list
     Subject: Re: gEDA-user: Magnetic bike operation
     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 <
     [4]dkerber@xxxxxxxxxxxxxxxxxxxxxxxxxx> 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: [5]geda-user-bounces@xxxxxxxxxxxxxx
     [mailto:[6]geda-user-bounces@xxxxxxxxxxxxxx] 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 <
     [7]dkerber@xxxxxxxxxxxxxxxxxxxxxxxxxx> 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: [8]geda-user-bounces@xxxxxxxxxxxxxx
     [mailto:[9]geda-user-bounces@xxxxxxxxxxxxxx] 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
     [10]geda-user@xxxxxxxxxxxxxx
     [11]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user

     _______________________________________________
     geda-user mailing list
     [12]geda-user@xxxxxxxxxxxxxx
     [13]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user

     _______________________________________________
     geda-user mailing list
     [14]geda-user@xxxxxxxxxxxxxx
     [15]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user

     --
     Dave McGuire
     Port Charlotte, FL

   _______________________________________________
   geda-user mailing list
   [16]geda-user@xxxxxxxxxxxxxx
   [17]http://www.seul.org/cgi-bin/mailman/listinfo/geda-user

References

   1. mailto:mcguire@xxxxxxxxxxxxx
   2. mailto:geda-user-bounces@xxxxxxxxxxxxxx
   3. mailto:geda-user-bounces@xxxxxxxxxxxxxx
   4. mailto:dkerber@xxxxxxxxxxxxxxxxxxxxxxxxxx
   5. mailto:geda-user-bounces@xxxxxxxxxxxxxx
   6. mailto:geda-user-bounces@xxxxxxxxxxxxxx
   7. mailto:dkerber@xxxxxxxxxxxxxxxxxxxxxxxxxx
   8. mailto:geda-user-bounces@xxxxxxxxxxxxxx
   9. mailto:geda-user-bounces@xxxxxxxxxxxxxx
  10. mailto:geda-user@xxxxxxxxxxxxxx
  11. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
  12. mailto:geda-user@xxxxxxxxxxxxxx
  13. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
  14. mailto:geda-user@xxxxxxxxxxxxxx
  15. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
  16. mailto:geda-user@xxxxxxxxxxxxxx
  17. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user