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Date: Wed, 27 Mar 2013 17:15:32 -0400
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Subject: Re: [geda-user] Magnetic Exercise Bike design with a stator and rotor
From: Rob Butts <r DOT butts2 AT gmail DOT com>
To: geda-user AT delorie DOT com
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I got a stator and flywheel and my problem is that the stator has a 4 wires
coming from the stator and I don't have a schematic. There is a green wire
which is screwed to ground. The rest, a yellow, a white and a red with blue
stripped that all appear to go to different coils.

I'm thinking these are three phases of an ac stator? My thought is to have
the pedals spinning a shaft that the flywheel is tied to. Then I'd vary the
votage going to each phase (dc voltage) which would produce a magnetic
field and resistance to the pedaling.

Any thoughts?

Thanks,

Rob


On Tue, Mar 26, 2013 at 3:44 PM, Rob Butts <r DOT butts2 AT gmail DOT com> wrote:

> I do understand how the magnetic field varies in the road bike trainer and
> kind of understand the eddy current braking theory.  I did get an eight
> coil stator and flywheel that I thought I'd experiment with.  In the see
> also section of the eddy current brake wiki page there is a link for Telma
> retarders and towards the bottom of that page a section describing an
> electric retarder which sounds exactly what I need and what I can use this
> $14 stator and flywheel for.  I think I just have to gear the speed of the
> flywheel as high as I can which at this point is 5 to 1.
>
>
> On Mon, Mar 25, 2013 at 10:13 AM, John Griessen <john AT ecosensory DOT com>wrote:
>
>> On 03/24/2013 03:58 PM, Rob Butts wrote:
>>
>>> One plastic disc is fixed and the opposing plastic disk is allowed to
>>> rotate 30 degrees providing the variable magnetic field and
>>> variable resistance.  I have not been able to simulate the resistance I
>>> believe because I'm not providing the same rotational
>>> velocity of the aluminum disc.
>>>
>>
>> Sounds like the out of alignment of the discs makes the field vary from
>> weak to strong.
>> To have strong fields, each magnet needs to be straight across, (through
>> the aluminum disc),
>> from another with same polarity direction.  Then induced currents flowing
>> in circles around the strong field area
>> counter subsequent motion by a force of their own.  I've never quite
>> grasped how that force stays local
>> to any place in the aluminum plate though...perhaps inertia of electrons?
>>  Else moving the path of the high
>> eddying current is more resistive than the eddy path?  It's all so
>> circular!  I feel like researching
>> and reading about it instead of doing my taxes...
>>
>> What do you mean by simulate?  What velocity can you get?
>>
>> Some decent velocity is needed for small inexpensive magnets.  I've seen
>> a demo
>> of eddy current braking done with a pendulum hung plate, then a slotted
>> plate
>> for comparison, where the opposing magnets were very massive and with
>> iron looping
>> around to make a complete magnetic circle path with two short gaps, (
>> where the aluminum
>> plate moved).  It would slow the pendulum in one stroke by 4/5ths.  It
>> must have weighed
>> 80 lbs.
>>
>> An alternator will need velocity also.  Bicycle gearing can get you
>> velocity.
>>
>
>

--20cf307abe7fc6ab7204d8ee896b
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<font size=3D"3" face=3D"Times New Roman">

</font><p><font size=3D"3"><font face=3D"Times New Roman">I got a stator an=
d flywheel and my problem is that the stator has a 4 wires coming from the =
stator and I
don&#39;t have a schematic. There is a green wire which is screwed to groun=
d. The
rest, a yellow, a white and a red with blue stripped that all appear to go =
to
different coils. </font></font></p><font size=3D"3" face=3D"Times New Roman=
">

</font><p><font size=3D"3"><font face=3D"Times New Roman">I&#39;m thinking=
=A0these=A0are three phases of=A0an=A0ac=A0stator? My thought is to have th=
e pedals
spinning a shaft that the flywheel is tied to. Then I&#39;d vary the votage=
 going
to each phase (dc voltage) which would produce a magnetic field and=A0resis=
tance to the pedaling.</font></font></p><font size=3D"3" face=3D"Times New =
Roman">

</font><p><font size=3D"3"><font face=3D"Times New Roman">Any=A0thoughts?</=
font></font></p><font size=3D"3" face=3D"Times New Roman">

</font><p><font size=3D"3"><font face=3D"Times New Roman">Thanks,</font></f=
ont></p><font size=3D"3" face=3D"Times New Roman">

</font><p><font size=3D"3"><font face=3D"Times New Roman">Rob</font></font>=
</p><br><br><div class=3D"gmail_quote">On Tue, Mar 26, 2013 at 3:44 PM, Rob=
 Butts <span dir=3D"ltr">&lt;<a href=3D"mailto:r DOT butts2 AT gmail DOT com" target=
=3D"_blank">r DOT butts2 AT gmail DOT com</a>&gt;</span> wrote:<br>
<blockquote style=3D"margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-=
color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class=
=3D"gmail_quote">I do=A0understand how the magnetic field varies in the roa=
d bike trainer and kind of understand the eddy current braking theory.=A0 I=
 did get an eight coil stator and flywheel that I thought I&#39;d experimen=
t with.=A0 In the see also section of the eddy current brake wiki page ther=
e is a link for Telma retarders and towards the bottom of that page a secti=
on describing an electric retarder which sounds exactly what I need and wha=
t I can use this $14 stator and flywheel for.=A0 I think I just have to gea=
r the speed of the flywheel as high as I can which at this point is 5 to 1.=
<div class=3D"HOEnZb">
<div class=3D"h5"><br>
<br><div class=3D"gmail_quote">On Mon, Mar 25, 2013 at 10:13 AM, John Gries=
sen <span dir=3D"ltr">&lt;<a href=3D"mailto:john AT ecosensory DOT com" target=3D"=
_blank">john AT ecosensory DOT com</a>&gt;</span> wrote:<br><blockquote style=3D"m=
argin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204)=
;border-left-width:1px;border-left-style:solid" class=3D"gmail_quote">

<div>On 03/24/2013 03:58 PM, Rob Butts wrote:<br>
<blockquote style=3D"margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-=
color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class=
=3D"gmail_quote">
One plastic disc is fixed and the opposing plastic disk is allowed to rotat=
e 30 degrees providing the variable magnetic field and<br>
variable resistance. =A0I have not been able to simulate the resistance I b=
elieve because I&#39;m not providing the same rotational<br>
velocity of the aluminum disc.<br>
</blockquote>
<br></div>
Sounds like the out of alignment of the discs makes the field vary from wea=
k to strong.<br>
To have strong fields, each magnet needs to be straight across, (through th=
e aluminum disc),<br>
from another with same polarity direction. =A0Then induced currents flowing=
 in circles around the strong field area<br>
counter subsequent motion by a force of their own. =A0I&#39;ve never quite =
grasped how that force stays local<br>
to any place in the aluminum plate though...perhaps inertia of electrons? =
=A0Else moving the path of the high<br>
eddying current is more resistive than the eddy path? =A0It&#39;s all so ci=
rcular! =A0I feel like researching<br>
and reading about it instead of doing my taxes...<br>
<br>
What do you mean by simulate? =A0What velocity can you get?<br>
<br>
Some decent velocity is needed for small inexpensive magnets. =A0I&#39;ve s=
een a demo<br>
of eddy current braking done with a pendulum hung plate, then a slotted pla=
te<br>
for comparison, where the opposing magnets were very massive and with iron =
looping<br>
around to make a complete magnetic circle path with two short gaps, ( where=
 the aluminum<br>
plate moved). =A0It would slow the pendulum in one stroke by 4/5ths. =A0It =
must have weighed<br>
80 lbs.<br>
<br>
An alternator will need velocity also. =A0Bicycle gearing can get you veloc=
ity.<br>
</blockquote></div><br>
</div></div></blockquote></div><br>

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