Maker Pro
Maker Pro

axial flux planar stator

J

Jamie Morken

Jan 1, 1970
0
Hi,

Here is a stator design I made for an axial flux ironless motor:

http://rocketresearch.nekrom.com/new/planar stator/stator.jpg

There is one layer per phase (3phases) and the stator would be
compressed to maximize copper density in the active areas between
the magnets (magnets go above and below the stator)

The other way to make them is to wind a lot of wire and then
encase the stator in epoxy. I think the best way to make this
is to have it etched off copper foil backed with plastic,
polyimide/kapton thin sheet to hold the spaghetti wires in place.

I was thinking it could be waterjet cut or laser cut, but then
the wires would have no support unless/until plastic was reglued
to them.

Any comments/ideas?

cheers,
Jamie
 
J

Jamie Morken

Jan 1, 1970
0
Jamie said:
Hi,

Here is a stator design I made for an axial flux ironless motor:

http://rocketresearch.nekrom.com/new/planar stator/stator.jpg

There is one layer per phase (3phases) and the stator would be
compressed to maximize copper density in the active areas between
the magnets (magnets go above and below the stator)

The other way to make them is to wind a lot of wire and then
encase the stator in epoxy. I think the best way to make this
is to have it etched off copper foil backed with plastic,
polyimide/kapton thin sheet to hold the spaghetti wires in place.

I was thinking it could be waterjet cut or laser cut, but then
the wires would have no support unless/until plastic was reglued
to them.

Any comments/ideas?

cheers,
Jamie


Oh ya, anyone know a place that sells rolls of copper foil (0.01" or
0.015" thick) that is backed with 0.001" or thinner kapton or similar?
:) The thickest stock I've seen for this is for FPC flex print circuits
and is 5oz which is about 0.0068" thick I believe, so looking for 8oz
and up copper on thin plastic if it exists.

cheers,
Jamie
 
J

John Larkin

Jan 1, 1970
0
Hi,

Here is a stator design I made for an axial flux ironless motor:

http://rocketresearch.nekrom.com/new/planar stator/stator.jpg

There is one layer per phase (3phases) and the stator would be
compressed to maximize copper density in the active areas between
the magnets (magnets go above and below the stator)

The other way to make them is to wind a lot of wire and then
encase the stator in epoxy. I think the best way to make this
is to have it etched off copper foil backed with plastic,
polyimide/kapton thin sheet to hold the spaghetti wires in place.

I was thinking it could be waterjet cut or laser cut, but then
the wires would have no support unless/until plastic was reglued
to them.

Any comments/ideas?

cheers,
Jamie

We've made stuff like this (current shunts, delay-line position
detectors) by photoetching manganin or beryllium copper. For the more
complex/delicate structures, you leave webs or a "carrier" section of
solid material around the outside to hold things together during
handling, which you can dremel away after things are laminated or
whatever.

Here's part of a 2-D delay-line anode thing, for imaging ion hits on a
microchannel plate.

http://img132.imageshack.us/my.php?image=anode2xq8.jpg

It's thin, soft copper, and is fairly delicate. This one has been
kicking around for a while. I think some pancake motor rotors are made
this way.

Are you spinning the magnets? That's a lot of inertia.

John
 
T

Tony

Jan 1, 1970
0
Hi,

Here is a stator design I made for an axial flux ironless motor:

http://rocketresearch.nekrom.com/new/planar stator/stator.jpg

There is one layer per phase (3phases) and the stator would be
compressed to maximize copper density in the active areas between
the magnets (magnets go above and below the stator)

The other way to make them is to wind a lot of wire and then
encase the stator in epoxy. I think the best way to make this
is to have it etched off copper foil backed with plastic,
polyimide/kapton thin sheet to hold the spaghetti wires in place.

I was thinking it could be waterjet cut or laser cut, but then
the wires would have no support unless/until plastic was reglued
to them.

Any comments/ideas?

cheers,
Jamie

I would think that you would need to address the "compression" geometry issue first, as
that would all but rule out the simple "plane per phase" approach - ie, the magnet energy
required is proportional to airgap length, which is 3x longer than really necessary with
the 3-plane construction. So the first thing is to get the radial legs of all 3 phases
coplanar (where they pass through the flux), but allow a different form of
interconnections, which has its own optimum geometry. Maybe put all the radials ion one
side and all the interconnects on the other side of a 2 layer PTH PCB, then plate it up?
Or maybe you can etch the radials on a plane and the connections on two tubes (all of very
thin Cu+substrate, assemble them as a tight fit (so the traces touch) then heavily plate
up the Cu and make the joints?

Tony
 
J

Jamie Morken

Jan 1, 1970
0
John said:
We've made stuff like this (current shunts, delay-line position
detectors) by photoetching manganin or beryllium copper. For the more
complex/delicate structures, you leave webs or a "carrier" section of
solid material around the outside to hold things together during
handling, which you can dremel away after things are laminated or
whatever.

Here's part of a 2-D delay-line anode thing, for imaging ion hits on a
microchannel plate.

http://img132.imageshack.us/my.php?image=anode2xq8.jpg

Hi John,

Looks very intricate, how did you keep the wires from going into
spaghetti mode? :) What is the depth/thickness of that copper
anode? I'd like to do exactly the same thing but only etch from
one side and have a thin plastic backing on the other side to hold
the wires in place.
It's thin, soft copper, and is fairly delicate. This one has been
kicking around for a while. I think some pancake motor rotors are made
this way.

Are you spinning the magnets? That's a lot of inertia.

Yes is a brushless outrunner design, lots of rotor weight :)

cheers,
Jamie
 
J

Jamie Morken

Jan 1, 1970
0
Tony said:
I would think that you would need to address the "compression" geometry issue first, as
that would all but rule out the simple "plane per phase" approach - ie, the magnet energy
required is proportional to airgap length, which is 3x longer than really necessary with
the 3-plane construction. So the first thing is to get the radial legs of all 3 phases
coplanar (where they pass through the flux), but allow a different form of

Hi Tony,

I think if the sheets are flexible and the radials have a bit extra
length it may be possible to compress them into more or less one plane
at least in the area between the magnets. I am not sure though.
interconnections, which has its own optimum geometry. Maybe put all the radials ion one
side and all the interconnects on the other side of a 2 layer PTH PCB, then plate it up?

The PCB would have to be flex print technology to keep it thin I think,
and the max copper thickness I've heard for this is 5oz standard, but is
it possible to plate it up thicker in a plating bath as you say? I
guess if the copper was left uncoated it could be put in a standard
copper plating bath?
Or maybe you can etch the radials on a plane and the connections on two tubes (all of very
thin Cu+substrate, assemble them as a tight fit (so the traces touch) then heavily plate
up the Cu and make the joints?

That may involve a lot of work to assemble the inner and outer tubes and
solder them to the radials I think but maybe there is a quick way to do
it.

cheers,
Jamie
 
Top