lrk-torquemax : Messages : 12477-12506 of 12506

I'm wondering, do the magnets rotate in the same direction as the
electromagnetic field or the opposite direction, in an LRK motor?
Thanks,

Kip

#12505

From: "taadys" <minotel@...>
Date: Fri Dec 18, 2009 7:57 pm
Subject: Re: [lrk] Axial flux motor (was: Low rpm, high torque)

taadys

Offline

HI, I have question about coil core.I started to build motor with disc with 12
neo magnets and 9x2 coils(I mean 9 from both sides of disc).So if I'll make coil
core 25 mm and wrap wire just 15 mm on it and fasten coil the way that core end
without wire will be closer to disc?Will this setup decrease magnetic power of
coil?Sorry for my english.

Reply | Forward | Messages in this Topic (11)

#12504

From: Louis FOURDAN <fourdanlouis@...>
Date: Wed Dec 16, 2009 9:27 pm
Subject: Re : Re : [lrk] RoV motors

fourdanlouis

Online Now

Hi Antony

Scorpion kits are here
http://www.innov8tivedesigns.com
For example S 4025 price 94.99$ weight 353 g Power about 800W

From stock motors you are informed about Kv x turns constant product
Then from your desired Kv you can compute desired turns number Wye or Delta

For example, if you need 500 rpm under 12V
you need Kv around = 500/12x 1.15 = 47.9 rpm/V
Stock motor S4025-16 has a Kv = 332 rpm/V
It is 8 turns per tooth (16 turns per pair dLRK) connected Delta

So you need   8 x 332 / 47.9 / 1.74 = 32 turns per tooth connected Wye
Stock S4025616 is wound 18-Strand  0.25mm (30 AWG)
So you could try 5 strands 0.25 mm windings (18 strands / 4 rounded to 5
strands)
Just an example to get 500 rpm under 12V

Louis
living in city : ANTONY (France) !!!!






________________________________
De : antony7040 <antony.gilbert@...>
À : lrk-torquemax@yahoogroups.com
Envoyé le : Mer 16 Décembre 2009, 12 h 06 min 29 s
Objet : [lrk] RoV motors


Hi
I have a underwater robot and are using brushless motors from a shop.
I would like to have a go at making my own motors. I cannot make the stators etc
but I can do the windings.
This is were I need the help :- i need to have a slow RPM, high Torque, low
amps, and with a working voltage of 12-15 volts and if possible work with a
standard ESC.
Can someone recommend a kit that can meet the requirements ??
Physical size and weight is not a issue.
I reside in the U.k.

Regards Antony







[Non-text portions of this message have been removed]

#12501

From: "antony7040" <antony.gilbert@...>
Date: Wed Dec 16, 2009 11:06 am
Subject: RoV motors

antony7040

Offline

Hi
I have a underwater robot and are using brushless motors from a shop.
I would like to have a go at making my own motors. I cannot make the stators etc
but I can do the windings.
This is were I need the help :- i need to have a slow RPM, high Torque, low
amps, and with a working voltage of 12-15 volts and if possible work with a
standard ESC.
Can someone recommend a kit that can meet the requirements ??
Physical size and weight is not a issue.
I reside in the U.k.

Regards Antony

#12500

From: Paul O'Rorke <paul@...>
Date: Tue Dec 15, 2009 10:48 pm
Subject: Re: [lrk] motor building software-

pororke2000

Offline

Awesome - I too want it for an in hub design...  we started fabrication
more than a year ago but a divorce has taken it's toll and the project
stalled.  It might be time to revisit it...


         Paul O'Rorke

         paul@... <mailto:paul@...>
         paulororke.net <http://paulororke.net>


On 15/12/2009 12:28 PM, Minority Report wrote:
>
> thats the one! was trying an in wheel design. it would be large,
> something like 75mm dia, and just needed an idea of current
> possibilities. im working on the motor controller now, but have ran
> into trouble with the controller....
>
> --- In lrk-torquemax@yahoogroups.com
> <mailto:lrk-torquemax%40yahoogroups.com>, Pete Burchell
> <spoke2570@...> wrote:
> >
> >
> > Paul
> >
> > I think that was the original excel version of Drive Calculator. The
> stator dims were used to predict permissible current density in the
> windings.
> >
> > The current version is pretty nice, available for Mac or PC. It
> includes automated updates to it's pretty large catalog of motors,
> batteries, and props. It allows one to add their own equipment. There
> is a feature in the Reconfigurator tool that allows one to
> > reconfigure the stator stack height of a known stator and get
> > performance predictions. It also grades its own predictions with
> respect to accuracy.
> >
> > It can be found here: http://www.drivecalc.de/
> <http://www.drivecalc.de/>
> >
> > Christian Lucas has a nice motor calculator. I don't remember that
> address, though.
> >
> > pete b
> >
> > To: lrk-torquemax@yahoogroups.com
> <mailto:lrk-torquemax%40yahoogroups.com>
> > From: paul@...
> > Date: Mon, 14 Dec 2009 15:30:49 -0800
> > Subject: Re: [lrk] motor building software-
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > I don't now but if you ever do find it again I'd love to see it too...
> >
> > Can you check your browser history at work? You might be able to find
> >
> > the referring page that way.
> >
> >
> >
> > Paul O'Rorke
> >
> >
> >
> > paul@... <mailto:paul@...>
> >
> > paulororke.net <http://paulororke.net <http://paulororke.net>>
> >
> >
> >
> > On 08/11/2009 6:19 AM, Minority Report wrote:
> >
> > >
> >
> > > hello. first id just like to say how great this group is. in my
> >
> > > wandering the other day i came across a downloadable program(which
> was
> >
> > > free of course) that had a wealth of information on building a motor.
> >
> > > you could program in your stator teeth demensions, wire gauge, and it
> >
> > > would give you all sorts of information. unfortuneatly i was at work
> >
> > > at the time and unable to DL it, and have since been unable to find
> >
> > > it- does anyone have or recall this program?
> >
> > >
> >
> > >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > __________________________________________________________
> > Hotmail: Free, trusted and rich email service.
> > http://clk.atdmt.com/GBL/go/171222984/direct/01/
> <http://clk.atdmt.com/GBL/go/171222984/direct/01/>
> >
> > [Non-text portions of this message have been removed]
> >
>
>


[Non-text portions of this message have been removed]

#12499

From: "Minority Report" <commanderkraut@...>
Date: Tue Dec 15, 2009 8:28 pm
Subject: Re: [lrk] motor building software-

commanderkraut

Offline

thats the one! was trying an in wheel design. it would be large, something like
75mm dia, and just needed an idea of current possibilities. im working on the
motor controller now, but have ran into trouble with the controller....

--- In lrk-torquemax@yahoogroups.com, Pete Burchell <spoke2570@...> wrote:
>
>
> Paul
>
> I think that was the original excel version of Drive Calculator. The stator
dims were used to predict permissible current density in the windings.
>
> The current version is pretty nice, available for Mac or PC. It includes
automated updates to it's pretty large catalog of motors, batteries, and props.
It allows one to add their own equipment. There is a feature in the
Reconfigurator tool that allows one to
> reconfigure the stator stack height of a known stator and get
> performance predictions. It also grades its own predictions with respect to
accuracy.
>
> It can be found here: http://www.drivecalc.de/
>
> Christian Lucas has a nice motor calculator. I don't remember that address,
though.
>
> pete b
>
> To: lrk-torquemax@yahoogroups.com
> From: paul@...
> Date: Mon, 14 Dec 2009 15:30:49 -0800
> Subject: Re: [lrk] motor building software-
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>       I don't now but if you ever do find it again I'd love to see it too...
>
> Can you check your browser history at work?  You might be able to find
>
> the referring page that way.
>
>
>
> Paul O'Rorke
>
>
>
> paul@... <mailto:paul@...>
>
>         paulororke.net <http://paulororke.net>
>
>
>
> On 08/11/2009 6:19 AM, Minority Report wrote:
>
> >
>
> > hello. first id just like to say how great this group is. in my
>
> > wandering the other day i came across a downloadable program(which was
>
> > free of course) that had a wealth of information on building a motor.
>
> > you could program in your stator teeth demensions, wire gauge, and it
>
> > would give you all sorts of information. unfortuneatly i was at work
>
> > at the time and unable to DL it, and have since been unable to find
>
> > it- does anyone have or recall this program?
>
> >
>
> >
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> _________________________________________________________________
> Hotmail: Free, trusted and rich email service.
> http://clk.atdmt.com/GBL/go/171222984/direct/01/
>
> [Non-text portions of this message have been removed]
>

#12498

From: Pete Burchell <spoke2570@...>
Date: Tue Dec 15, 2009 2:14 pm
Subject: RE: [lrk] motor building software-

burswelt

Offline

Paul

I think that was the original excel version of Drive Calculator. The stator dims
were used to predict permissible current density in the windings.

The current version is pretty nice, available for Mac or PC. It includes
automated updates to it's pretty large catalog of motors, batteries, and props.
It allows one to add their own equipment. There is a feature in the
Reconfigurator tool that allows one to
reconfigure the stator stack height of a known stator and get
performance predictions. It also grades its own predictions with respect to
accuracy.

It can be found here: http://www.drivecalc.de/

Christian Lucas has a nice motor calculator. I don't remember that address,
though.

pete b

To: lrk-torquemax@yahoogroups.com
From: paul@...
Date: Mon, 14 Dec 2009 15:30:49 -0800
Subject: Re: [lrk] motor building software-

       I don't now but if you ever do find it again I'd love to see it too...

Can you check your browser history at work?  You might be able to find

the referring page that way.

Paul O'Rorke

paul@... <mailto:paul@...>

         paulororke.net <http://paulororke.net>

On 08/11/2009 6:19 AM, Minority Report wrote:

>

> hello. first id just like to say how great this group is. in my

> wandering the other day i came across a downloadable program(which was

> free of course) that had a wealth of information on building a motor.

> you could program in your stator teeth demensions, wire gauge, and it

> would give you all sorts of information. unfortuneatly i was at work

> at the time and unable to DL it, and have since been unable to find

> it- does anyone have or recall this program?

>

>

[Non-text portions of this message have been removed]

_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/171222984/direct/01/

[Non-text portions of this message have been removed]

#12497

From: Paul O'Rorke <paul@...>
Date: Mon Dec 14, 2009 11:30 pm
Subject: Re: [lrk] motor building software-

pororke2000

Offline

I don't now but if you ever do find it again I'd love to see it too...
Can you check your browser history at work?  You might be able to find
the referring page that way.


         Paul O'Rorke

         paul@... <mailto:paul@...>
         paulororke.net <http://paulororke.net>


On 08/11/2009 6:19 AM, Minority Report wrote:
>
> hello. first id just like to say how great this group is. in my
> wandering the other day i came across a downloadable program(which was
> free of course) that had a wealth of information on building a motor.
> you could program in your stator teeth demensions, wire gauge, and it
> would give you all sorts of information. unfortuneatly i was at work
> at the time and unable to DL it, and have since been unable to find
> it- does anyone have or recall this program?
>
>


[Non-text portions of this message have been removed]

#12496

From: "paulstrotten" <strotten@...>
Date: Fri Dec 11, 2009 11:17 am
Subject: Re: High toque Axial flux motor

paulstrotten

Offline

Hi Ron
Thankyou for correcting me on hall sensors. so with 12 magnets 9 coils  ratio =
6. am I right in thinking halls get fitted at 30deg intervals.

Many Thanks
Paul

--- In lrk-torquemax@yahoogroups.com, "ron_van_sommeren" <ron.van.sommeren@...>
wrote:
>
> Goedendag Paul and all,
>
>
> > I realise using LRK type winding cannot use hall sensors ...
> No problem, hall sensors can be used with _all_ winding diagrams.
>
> Vriendelijke groeten ;-) Ron van Sommeren
> near Nijmegen, the Netherlands
>

#12495

From: "ryanbiffard" <ryanbiffard@...>
Date: Tue Dec 8, 2009 9:11 pm
Subject: Lamination Bonding

ryanbiffard

Offline

I am curious to learn from your collective experience what adhesives work best
to bond core laminations.  What adhesives have you used and what did you like
about them?

I am considering using loctite 290, which is a wicking thread locker with a
temperature rating of 150 C. I like the idea of using a wicking adheasive so
that I can stack the laminations, then just brush on a little adhesive along the
sides and let capillary action pull the adheasive into the core, then apply
pressure and let it set quickly (less than 20 minutes).  For me, assembly time
is a high priority, I would rather not have to apply adhesive to each layer of
the lamination, since I need to laminate 4000 pieces.

Have any of you had experience with wicking adhesives rather than having to
apply adhesive manually between each piece?

#12494

From: "ron_van_sommeren" <ron.van.sommeren@...>
Date: Tue Dec 8, 2009 3:21 pm
Subject: Re: High toque Axial flux motor

ron_van_somm...

Offline

Goedendag Paul and all,


> I realise using LRK type winding cannot use hall sensors ...
No problem, hall sensors can be used with _all_ winding diagrams.

Vriendelijke groeten ;-) Ron van Sommeren
near Nijmegen, the Netherlands

#12493

From: "paulstrotten" <strotten@...>
Date: Tue Dec 8, 2009 11:29 am
Subject: Re: High toque Axial flux motor

paulstrotten

Offline

Hi
Please can someone explain how to size magnets for Axial flux motor to give
desired toque. ie with 2 magnet disc & stator coils between, is there simple
formula.

Thanks Paul

#12492

From: Sandra Pogue <sandra_pogue@...>
Date: Sun Dec 6, 2009 7:39 pm
Subject: Hand Dryers in Restrooms

sandra_pogue

Offline

Hand Dryers in Restrooms

hmmmm. Don't know if this is true, but it is something to think about.

Everyone in the cleaning industry has always been told that hand dryers
in restrooms are not sanitary, they spread germs and bacteria around.
I always thought that this just came from the paper companies because
they are loosing sales to the hand dryers. A couple of years ago, I
was working with a rep, and I noticed that after he washed his hands
and noticed that there were no paper towels, only a hand dryer he left
the restroom with wet hands. I asked him about it. He said that hand
dryers blow a lot of germs and bacteria around. He also told me to
take a look under the hand dryer next time I was in a restroom. There
is a filter underneath the hand dryer that is supposed to be cleaned on
a weekly basis. I looked at one and it looked like it hadn't been
cleaned in years. It had layers and layers of caked on
gunk (disgusting) . Since then I will not use hand dryers in
restrooms. Now this is where the story gets really interesting. The
schools and universities that have had the H1N1 (swine flue) outbreak
this year are being told by the health department that they have
to take out all of their hand dryers and replace them with towel
dispensers because the hand dryers are spreading disease. Please pass
this along so everyone knows not to use hand dryers.




[Non-text portions of this message have been removed]

#12491

From: "paulstrotten" <strotten@...>
Date: Fri Dec 4, 2009 11:53 pm
Subject: High toque Axial flux motor

paulstrotten

Offline

Hi all
Have been reading this forum for many months with much interest. Have built
axial flux motor for testing. spec magnets 24 0ff 15x5x1mm (12 on each 70mm dia
disc), 9 coils 5mm wide, 180 turns 0.25mm copper wire, air gap 0.5mm. Very
pleased with results. 12v, 9A stall, no load 4600RPM, would like to understand
how to design for high toque low RPM possibly max  1000RPM. This is for direct
drive to ball screw for CNC type  mc. I realise using LRK type winding cannot
use hall sensors but hope to use encoder & look up table in pic chip or similar.
Any clue re size magnets & toque ratio.

Many Thanks
Paul

#12490

From: Pete Burchell <spoke2570@...>
Date: Wed Dec 2, 2009 7:03 am
Subject: RE: [lrk] Re: Low kV Small Motors

burswelt

Offline

Those low kv, <50W motors make great slow flier motors. ..hour long flights, and
enough power to carry a payload on 2000mAh 2 or 3 cell packs.

pete b

To: lrk-torquemax@yahoogroups.com
From: rick-page@...
Date: Wed, 2 Dec 2009 04:02:47 +0000
Subject: [lrk] Re: Low kV Small Motors

       > So "higher voltage" should always be chosen if possible?

>(Power lost = I^2 * R)

Fewer cells are easier to manage for charging and pack building and at low
currents i^2r is negligible. As current increases, only then do the hassles of
high voltage packs become worthwhile. A 6 cell 50 mah pack would have more
weight in balancing taps than in the battery itself.

The 7-cell NiCd pack and a Speed 400 motor made electric flight accessible to
the masses and the 2 or 3-cell LiPo for <50W airplanes is in that niche now.

Rick.

_________________________________________________________________
Chat with Messenger straight from your Hotmail inbox.
http://www.microsoft.com/windows/windowslive/hotmail_bl1/hotmail_bl1.aspx?ocid=P\
ID23879::T:WLMTAGL:ON:WL:en-ww:WM_IMHM_4:092009

[Non-text portions of this message have been removed]

#12489

From: "Rick Page" <rick-page@...>
Date: Wed Dec 2, 2009 4:02 am
Subject: [lrk] Re: Low kV Small Motors

rick_page53

Offline

> So "higher voltage" should always be chosen if possible?
>(Power lost = I^2 * R)
Fewer cells are easier to manage for charging and pack building and at low
currents i^2r is negligible. As current increases, only then do the hassles of
high voltage packs become worthwhile. A 6 cell 50 mah pack would have more
weight in balancing taps than in the battery itself.

The 7-cell NiCd pack and a Speed 400 motor made electric flight accessible to
the masses and the 2 or 3-cell LiPo for <50W airplanes is in that niche now.

Rick.

#12488

From: "ManuLRK" <brushless@...>
Date: Mon Nov 30, 2009 7:46 pm
Subject: RE: [lrk] Re: Low kV Small Motors , high voltage

manulrk

Offline

Talking about high voltage battery packs.
http://www.hightechsystemsllc.com/pt_Batterypacks.html

   ManuLRK
>>Why are there so few small outrunners (30 to 100watts)
>>that have low kVs (700 to 900)?
>Most really small motors only use 1-3 cells to save weight so the kV
has to be higher to get useful rpm's. Currents are low at these sizes
but as motors get larger it is better to increase voltage and decrease
kV.
>Rick.
Single cell Lipo battery capacities are available from a few 100th mAh
to 1000th (10.000 ?) mAh ., weight should not be a reason why small
motors can't be run on higher voltages!?
So "higher voltage" should always be chosen if possible? (Power lost =
I^2 * R)
ManuLRK


<mailto:rick-page@shaw. <mailto:rick-page%40shaw.ca>
ca?subject=Re:%20Low%20kV%20Small%20Motors>
Reply to sender | Reply
<mailto:lrk-torquemax@ <mailto:lrk-torquemax%40yahoogroups.com>
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otors> to group
Messages
<http://groups.
<http://groups.yahoo.com/group/lrk-torquemax/message/12484;_ylc=X3oDMTM2
> yahoo.com/group/lrk-torquemax/message/12484;_ylc=X3oDMTM2
YTBpZmI4BF9TAzk3MzU5NzE0BGdycElkAzMyMDUzNDcEZ3Jwc3BJZAMxNzA1MzcwODA4BG1z
Z0lkAzEyNDg2BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTI1OTYwMjQ4NQR0cGNJZAMxMjQ4
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[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]

#12487

From: "ManuLRK" <brushless@...>
Date: Mon Nov 30, 2009 7:34 pm
Subject: RE: [lrk] Re: Low kV Small Motors

manulrk

Offline

>>Why are there so few small outrunners (30 to 100watts)
>>that have low kVs (700 to 900)?
>Most really small motors only use 1-3 cells to save weight so the kV
has to be higher to get useful rpm's. Currents are low at these sizes
but as motors get larger it is better to increase voltage and decrease
kV.
>Rick.
Single cell Lipo battery capacities are available from a few 100th  mAh
to 1000th (10.000 ?) mAh ., weight should not be a reason why small
motors can't be run on higher voltages!?
So "higher voltage" should always be chosen if possible? (Power lost =
I^2 * R)
ManuLRK


  <mailto:rick-page@...?subject=Re:%20Low%20kV%20Small%20Motors>
Reply to sender | Reply
<mailto:lrk-torquemax@yahoogroups.com?subject=Re:%20Low%20kV%20Small%20M
otors>  to group
Messages
<http://groups.yahoo.com/group/lrk-torquemax/message/12484;_ylc=X3oDMTM2
YTBpZmI4BF9TAzk3MzU5NzE0BGdycElkAzMyMDUzNDcEZ3Jwc3BJZAMxNzA1MzcwODA4BG1z
Z0lkAzEyNDg2BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTI1OTYwMjQ4NQR0cGNJZAMxMjQ4
NA-->  in this topic (3)



[Non-text portions of this message have been removed]

#12486

From: "Rick Page" <rick-page@...>
Date: Mon Nov 30, 2009 5:30 pm
Subject: Re: Low kV Small Motors

rick_page53

Offline

>Why are there so few small outrunners (30 to 100watts)
>that have low kVs (700 to 900)?
Most really small motors only use 1-3 cells to save weight so the kV has to be
higher to get useful rpm's. Currents are low at these sizes but as motors get
larger it is better to increase voltage and decrease kV.

Rick.

#12485

From: Louis FOURDAN <fourdanlouis@...>
Date: Sun Nov 29, 2009 10:47 pm
Subject: Re : [lrk] Low kV Small Motors

fourdanlouis

Online Now

Hi Bob
You are right, there are few outrunners < 50g with low Kv
additionaly to Himax there is his one
** Tahmazo ER1812-660 wght 28.4g announced Kv 660 rpm/V
I have no sample of it, and no test
If you go to 2212-2215 stator size (about 60-65g)  the choice is bigger (Pulso,
Motrolfly, Dualsky ..)

Or you have also some kits to DIY with a lot of turns -Wye
Louis




________________________________
De : Robert (Bob) P. Andris <bob@...>
À : lrk-torquemax@yahoogroups.com
Envoyé le : Sam 28 Novembre 2009, 19 h 51 min 12 s
Objet : [lrk] Low kV Small Motors


Question for Ron and all others.  Why are there so few small outrunners (30 to
100watts) that have low kVs (700 to 900)?  For instance, HiMaxx makes the
HC2212-0840, which is a 50watt motor with a kV of 850.

Thanks,
Bob
............ ......... ......... ......... ......... ......... ...
Robert P. Andris
12155 Terrence Ave.
Saratoga, CA 95070
USA

(408) 252-5469

bob@andrisfamily. net

LSF 004, AMA 5055







[Non-text portions of this message have been removed]

#12484

From: "Robert (Bob) P. Andris" <bob@...>
Date: Sat Nov 28, 2009 6:51 pm
Subject: Low kV Small Motors

bobandris

Offline

Question for Ron and all others.  Why are there so few small outrunners (30 to
100watts) that have low kVs (700 to 900)?  For instance, HiMaxx makes the
HC2212-0840, which is a 50watt motor with a kV of 850.

Thanks,
       Bob
............................................................
Robert P. Andris
12155 Terrence Ave.
Saratoga, CA 95070
USA

(408) 252-5469

bob@...

LSF 004, AMA 5055

#12483

From: Stefan Trethan <stefan_trethan@...>
Date: Fri Nov 27, 2009 2:24 pm
Subject: enamel wire

stefan_trethan

Offline

Helmut singer just got in one 75kg lot of enamel wire in possibly
useful diameters:
<http://www.surplusasnew.de/stock/-263350915.html>

No affiliation, just spotted it and thought that may be useful for
someone making motors, lots of motors....

ST

#12482

From: Plpastore <plpastore@...>
Date: Sun Nov 22, 2009 11:55 pm
Subject: Re: [lrk] Magnet arc ou line?

plpastore

Offline

Yes,

I am grateful for the response, helped greatly.Grateful
Paulo

--- Em dom, 22/11/09, Rick Page <rick-page@...> escreveu:

De: Rick Page <rick-page@...>
Assunto: Re: [lrk] Magnet arc ou line?
Para: lrk-torquemax@yahoogroups.com
Data: Domingo, 22 de Novembro de 2009, 16:16
















 









       The list strips attachments so I didn't see your picture.



But the short answer is that arc magnets are better. If you consider a motor
will 2 poles and 2 flat magnets you can clearly see that the magnet is not very
effective. As the number of flat magnet segments goes up, it increasingly
approximates the field of a magnet that is already shaped in an arc.



However, given that, forming a magnet with a radius may not gain any advantages
over many flat segments. Flat magnets are cheaper and don't have to be created
to match each stator diameter.



Rick.




























      
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#12481

From: "Rick Page" <rick-page@...>
Date: Sun Nov 22, 2009 6:16 pm
Subject: Re: [lrk] Magnet arc ou line?

rick_page53

Offline

The list strips attachments so I didn't see your picture.

But the short answer is that arc magnets are better. If you consider a motor
will 2 poles and 2 flat magnets you can clearly see that the magnet is not very
effective. As the number of flat magnet segments goes up, it increasingly
approximates the field of a magnet that is already shaped in an arc.

However, given that, forming a magnet with a radius may not gain any advantages
over many flat segments. Flat magnets are cheaper and don't have to be created
to match each stator diameter.

Rick.

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#12480

From: dsteinke <dsteink@...>
Date: Thu Nov 19, 2009 4:39 pm
Subject: Re: [lrk] Re: big one

dsteink

Offline

The trick is to know  want want and the amount you want to spend.

Is this a battery powered/portable application?
What is your voltage source?
What is your rpm range?
What is your budget for motor, controller, power supply?
Do you need to adjust/control the rpm accurately?
Do you need use/control low end rpm (less than 20% of max) as well as
the high end?
Continuous at 2kw or intermittant?
Do you need to start the motor with a high load already on it?
How many do you need?

Hobbyking or Hobbycity has the

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5142&Product_\
Name=Turnigy_80-100-B_130Kv_Brushless_Outrunner_%28eq:_70-55%29

Which is a 130kv motor capable of 2kw on a continuous basis. Add a
$190 controller

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10332&Product\
_Name=Turnigy_Monster-2000_200A_4-12S_Brushless_ESC

and a RC servo servo tester and you are in basic business if the rpm
matches and so forth.

The problem with sensorless motors and controllers is that they cannot
start with a high torque load (they just sit there and buzz) and they
do not have good low speed (>20% max) speed control.

Let us know the answer to the above questions and maybe we can help
find a motor/controller that will work.

David Steinke
Tucson, AZ

On Thu, Nov 19, 2009 at 7:41 AM, pbp_et <pbp_et@...> wrote:
> There is or rather ARE: Try hobbyking.com
> regards
> Poul B�rge
>
> --- In lrk-torquemax@yahoogroups.com, "mike" <miker_54491@...> wrote:
>>
>> anyone know if there is a commercialy avalible 0utrunner in the 2kw range?
the company i work for uses a lot of off the shelf motots around that size.
usualy servos or steppers. but steppers are not making it because of the power
drop-off as the speed increases. servo prices startout at nuts and go up from
there...
>> Mike
>>
>
>
>
>
> ------------------------------------
>
> =======================================================================
> MOTOR BUILDING FAQs
> Excellent motorbuilding articles by Brian Mulder,they cover the all the
basics, a must read:
> http://www.southernsoaringclub.org.za/
> -> Articles by SouthEasterners.
> -> Electric Motors - part 1-5
>
> Do-it-yourself motor homepages, manuals/tutorials, checks and tests in this
motor builders tips and tricks thread. The checks and tests may save you from
*frying* your controller or motor. Thread is active, bookmark it for future
reference and subscribe to it:
> http://www.rcgroups.com/forums/showthread.php?t=240993 (sticky thread, at top
of subforum)
>
> =======================================================================
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#12479

From: Plpastore <plpastore@...>
Date: Thu Nov 19, 2009 5:05 pm
Subject: Re: [lrk] Magnet arc ou line?

plpastore

Offline

Dear
members,
�
Good day!
�
I have a question, as below:
�
Please, one question:
�
yellow shows loss of flow of the magnet and coil in the stator tooth
red shows continuity of flow of the magnet and coil in the stator tooth
Conclusion: magnet arc has a better answer magnet planar
�(see picture in attack)
�
A magnet that has arc, ie, which has a radius of curvature, it loses some of the
magnetic field, over another magnet that is rectangular planar without radius of
curvature. I, I think so, because the magnetic flux in a magnet with rectangular
planar surfaces, the flow is in the surrounding suburbs since the magnet arc, so
far as the fold closes in, there is proximity of the flow fields in the
extremities, thus an electric motor stator teeth are also borne by facilitating
the magnets pass in front, thus the magnet and the tooth and the two arcs, the
formation of magnetic flux meets tooth formation, as in the case of rectangular
planar magnet passing in front of the tooth of the stator, will present problems
of loss in the extremities, that the ends move away from the center of the tooth
with a greater reluctance among iron, so I ask: which of the magnets is better
in response normal rectangular or arc with radius equal to the radius of the
stator tooth,
  see the drawings to have a good understanding.
�
Best,
�
Paulo
�


      
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#12478

From: "pbp_et" <pbp_et@...>
Date: Thu Nov 19, 2009 2:41 pm
Subject: Re: big one

pbp_et

Offline

There is or rather ARE: Try hobbyking.com
regards
Poul B�rge

--- In lrk-torquemax@yahoogroups.com, "mike" <miker_54491@...> wrote:
>
> anyone know if there is a commercialy avalible 0utrunner in the 2kw range? the
company i work for uses a lot of off the shelf motots around that size. usualy
servos or steppers. but steppers are not making it because of the power drop-off
as the speed increases. servo prices startout at nuts and go up from there...
> Mike
>

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#12477

From: "ron_van_sommeren" <ron.van.sommeren@...>
Date: Thu Nov 19, 2009 9:22 am
Subject: Re: big one

ron_van_somm...

Offline