The basic idea is the same as a standard stepper motor using

http://www.gaussboys.com/ndfeb-magnets/D3712E.html
This is a very popular magnet that is almost impossible to separate
without the use of a table edge or some sort of sliding mechanism.
Black epoxy coated. This one holds up to 110 lbs.

I'm thinking of using 8 of these magnets near the edge of the wheel
and use 8 pairs of coils to drive the wheel. As I see it the advantage
would be that when power is not applied for example going down hill
or coasting the wheel would also work as a generator.

How do I calculate no of magnets needed, coils needed, and current
needed for a given amount of torque? or horse power?

Thanks in advance!
Robert

Robert Miller <stargazzr@windstream.net> wrote:
The basic idea is the same as a standard stepper motor using

http://www.gaussboys.com/ndfeb-magnets/D3712E.html
This is a very popular magnet that is almost impossible to separate
without the use of a table edge or some sort of sliding mechanism.
Black epoxy coated. This one holds up to 110 lbs.

I'm thinking of using 8 of these magnets near the edge of the wheel
and use 8 pairs of coils to drive the wheel. As I see it the advantage
would be that when power is not applied for example going down hill
or coasting the wheel would also work as a generator.

How do I calculate no of magnets needed, coils needed, and current
needed for a given amount of torque? or horse power?

Thanks in advance!
Robert

Get a good book on motors and generators and read it; the answer is
non-trivial and there are a lot more factors involved.

You've got that right! Anything that involves that level of math certianly

--
Jim Pennino

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jimp@specsol.spam.sux.com> wrote in message
news:s4bsv4-vna.ln1@mail.specsol.com...
Robert Miller <stargazzr@windstream.net> wrote:
The basic idea is the same as a standard stepper motor using

http://www.gaussboys.com/ndfeb-magnets/D3712E.html
This is a very popular magnet that is almost impossible to separate
without the use of a table edge or some sort of sliding mechanism.
Black epoxy coated. This one holds up to 110 lbs.

I'm thinking of using 8 of these magnets near the edge of the wheel
and use 8 pairs of coils to drive the wheel. As I see it the advantage
would be that when power is not applied for example going down hill
or coasting the wheel would also work as a generator.

How do I calculate no of magnets needed, coils needed, and current
needed for a given amount of torque? or horse power?

Thanks in advance!
Robert

Get a good book on motors and generators and read it; the answer is
non-trivial and there are a lot more factors involved.

You've got that right! Anything that involves that level of math
certianly
is not trivial Does anybody have a good book they could recomend?
I've looked and have found only a few good ones and they are either
too heavy on the math or too simple. I know Calculas would be a good
subject to have mastered, unfortunately...
--
Jim Pennino

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Robert Miller

Get a good book onmotorsandgeneratorsand read it; the answer is
non-trivial and there are a lot more factors involved.

--
Jim Pennino

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The best PM motor book that I know of is by Jim Hendershot and TJE
Miller. You can get it at Magnaphysics.

http://www.magnaphysics.com/design_of_brushless_permanent.htm

It goes into sizing equations, uses some good rules of thumb and then
shows you how it is done by hand. Be very aware that the
simplifications he use makes a lot of assumptions. There are also
current and thermal considerations. You also need an electronic drive
to act as a intermediate stage. This is an art and a science so it is
very non-trivial.

Get a good book onmotorsandgeneratorsand read it; the answer is
non-trivial and there are a lot more factors involved.

--
Jim Pennino

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If I can build a successful model you will all have been part of it.