How does this brake work?

[BlazerB52]

Found a electric brake online ( http://www.hobby-lobby.com/wheels.htmBrake.htm )and was wondering if anyone would have a good guess how it is made. I assume there is a coil in it. Would someone have an idea of its configuration internally. I would like to build one with my lathe and magnet wire I have.

Blazer

[Ron van Sommeren]

See these eddy current demos:
http://www.rcgroups.com/forums/showthread.php?t=465019

edit: The higher the speed, the more braking-action. Don't know if an eddy-current brake to zero speed or just a bit of creep left.

Vriendelijke groeten ;) Ron

[Almaz]

Just an idea and it should work. You can use from old computer, floppy drive step motor or any other types of step motors. A small step motor should give enough braking power using 5v-12v receiver battery pack to stop an airplane and it shouldn't lock the wheel. Also you can use step motor as anti lock brakes. Step motor must be installed as direct-drive wheel setup.

[BlazerB52]

Will this work?

[BlazerB52]

Just wound a test part from my diagram, it is magnetized on one end. :( Should have remembered the wire, nail and battery project as a kid. Does anyone have an idea about what type of wind I would need? :confused:

Blazer

[BlazerB52]

Here is my next try when I get time. Any comments?

[jjantti]

Hi Blazer

I have been thinking just about the same for a while. Anti-lock brakes on my BAe Hawk. For now this project is stalled due lack of time tough.

Any comments?
I would leave the center pin out of it. It must be force x distance so radius helps. And second I'd use CR-ROM motor as a base and neodym's instead of alum plate and eddy currents. Old brushed controller would do the shorting of coils. dunno actually :p

/Jyri

[Gord_W]

Here is my next try when I get time. Any comments?


You could get a more efficient clamping force by making your electro-mag horseshoe shaped. See Brake 1 picture

The original comment was to use an eddy current brake where the mag flux passes through a rotating disk. You can use a horseshoe style electo mag as shown in Brake 2 picture. The amount of braking force depends on the disk speed and the magnetic flux (current and number of turns). The nice thing about this is that you can't lock the brakes so you get passive anti-skid :cool:


Good luck!

Gord_W

[Brandano]

Just an idea and it should work. You can use from old computer, floppy drive step motor or any other types of step motors. A small step motor should give enough braking power using 5v-12v receiver battery pack to stop an airplane and it shouldn't lock the wheel. Also you can use step motor as anti lock brakes. Step motor must be installed as direct-drive wheel setup.
What use would the battery be? You can brake the motor simply by shorting out its windings. You might need some sort of current limiter, though. Stepper windings are quite thin, and the induced current could burn them. Another, approach to an eddy current brake would be to run a metal disk (copper, or aluminium, brass too perhaps) between the poles a C shaped magnet, using a servo to slide the magnet over the disk. this too will get really hot due to the induced currents. That's where the braking energy goes, you see

[BlazerB52]

Thanks for everyone's input so far. Does someone have a crude drawing of a setup with stator windings, ect. Trying to reduce width of unit to fit in the wing. Have lots of stator plates and can make a prototype from a drawing. Just can't figure out on my own how to impliment my ideas.

Blazer

[Almaz]

What use would the battery be? You can brake the motor simply by shorting out its windings. You might need some sort of current limiter, though. Stepper windings are quite thin, and the induced current could burn them. Another, approach to an eddy current brake would be to run a metal disk (copper, or aluminium, brass too perhaps) between the poles a C shaped magnet, using a servo to slide the magnet over the disk. this too will get really hot due to the induced currents. That's where the braking energy goes, you see


hmmm who said connecting step motor to the battery? You missed the point between the lines which was just an idea. Definitely to incorporate step motor as brake system people can add Microchip, L297, L298 and a lot more options. The beauty of the project that you can get all the parts for free as samples and make it work. The hardest part to mount step motor than making step motor work as brakes. I might be wrong but locking the front tires might cause a crash but ABS system should work better and it is so easy to make ABS system with step motors.

[AndyKunz]

Blazer,

MAN just had an article on making a dyno. Use the same principles on a smaller scale to understand what they're talking about here.

Andy

[Brandano]

hmmm who said connecting step motor to the battery? You missed the point between the lines which was just an idea. Definitely to incorporate step motor as brake system people can add Microchip, L297, L298 and a lot more options. The beauty of the project that you can get all the parts for free as samples and make it work. The hardest part to mount step motor than making step motor work as brakes. I might be wrong but locking the front tires might cause a crash but ABS system should work better and it is so easy to make ABS system with step motors.
No, my point is that you don't need to drive it. All that circuitry is overkill, when to make it into a brake you just have to allow induced current through its windings

[Ron van Sommeren]

See these eddy current demos:
http://www.rcgroups.com/forums/showthread.php?t=465019 ...The higher the speed, the higher the eddy-currents, and the more braking-action. No speed means no braking action. Don't know if an eddy-current based brake could get to zero speed or if there would be a bit of creep left.

An eddy-current brake in an dynamo-meter design. The platter, from a hard-disk, can get veryvery hot. More drawings/pictures/English
http://www.aerodesign.de/peter/2001/LRK350/EM-4-2001/LRK_EM_4_2001_eng.htm

Vriendelijke groeten ;) Ron