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Old Dec 22, 2003, 03:03 AM
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Tokyo, Japan
Joined Nov 2002
858 Posts
Re: Mitsumi model CRMC-FX001D

rysium,

That is the flat BL motor.
I used to fly my baby plane with it.
The magnetic efficiency is not so good.
You need small prop. or gear box with high RPM to get better efficiency.

Takao
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Old Dec 23, 2003, 01:54 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
1,714 Posts
Re: Re: Mitsumi model CRMC-FX001D

Quote:
Originally posted by Takao Shimizu
rysium,

That is the flat BL motor.
I used to fly my baby plane with it.
The magnetic efficiency is not so good.
Takao
Therefore there is my next original idea: Brushless Coreless (again).

Here is the deal:
From that motor use only ball bearings and rotor. I will use two CD-ROM motors to get one BL Coreless. See the picture:
- green = magnets (eight poles on each side - it's original CD-ROM rotor)
- orange = central coreless stator with 6 coils (new)
- blue = engine body with ball bearing mount on each side (new)
- black = shaft (2mm)
- grey = ball bearings from original motor

Rotors must be positioned that way, that N on one side alligns with S on the other.
Shis should be strong and efficient s.o.b. don't you think so?

Any thoughts?

RysiuM
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Old Dec 23, 2003, 02:07 AM
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Tokyo, Japan
Joined Nov 2002
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The problem is the thickness of coils.

Takao
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Old Dec 23, 2003, 02:30 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
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Quote:
Originally posted by Takao Shimizu
The problem is the thickness of coils.
Takao
What do you mean? To thick or to thin?

The original coil is 2 mm thick and about 3 mm of wire. So it seams possible to put 4x6=24 turns of 0.4mm wire - like we have in other BL conversion, and the air gap will be about 2mm more than in outrunners. But no core any more. 110% efficiency

RysiuM
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Old Dec 23, 2003, 04:41 AM
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Budapest
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2,572 Posts
Re: Re: Re: Mitsumi model CRMC-FX001D

Quote:
CD-ROM motors to get one BL Coreless. See the picture:
- green = magnets (eight poles on each side - it's original CD-ROM rotor)
What about an outer iron ring between the disks to close the flux path? The mechanical assembly becames tricky but not impossible.
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Last edited by mmormota; Dec 23, 2003 at 04:43 AM.
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Old Dec 23, 2003, 04:49 AM
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Take a look to this article: http://www.tip.csiro.au/Machines/papers/iwscem/
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Old Dec 23, 2003, 07:51 AM
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ssatoru's Avatar
Chiba, Japan
Joined Jan 2002
1,044 Posts
Re: DoppelWhopper

Quote:
Originally posted by Takao Shimizu

Obviously, 3s system is better by this result.
Yes, 3 cells are way to go. It also helps to get more power from LiPoly that has rather limited current supply.

I am still pushing Doppelwhopper. Double 0.3 mm 16T is fun at 58W+ with APC 6x5.5, ET1200 3S. Double 0.35 mm 10T exceeds 100W input Much easier to wind, too. I like it.

It is fortunate I have supply of long can CDROM motor although it is heavy. As a lathe impaired guy, I am looking at can of 280 or 370 motor for light alternative.

Satoru
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Old Dec 23, 2003, 08:08 AM
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Edmonds Wa. (Seattle)
Joined Nov 2003
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Speaking of lathes I just picked one up!
Now I will be able to make the parts I need (soon as I learn to use it) Now custom parts! like mounts and shafts with bearings pressed in, This machine is small 7x10 at only 21" long and 85lbs. though I have found out that it takes a little more then just the lathe Acc. are killing the bank There is a bunch of stuff I want to do with it + my son wants me to make him a Cannon for the 4th big bang
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Old Dec 24, 2003, 06:11 AM
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ssatoru's Avatar
Chiba, Japan
Joined Jan 2002
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Quote:
Originally posted by rcflyer2
Speaking of lathes I just picked one up!
Wow, that is a big Xmas present! Congratulations!

Satoru
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Old Dec 24, 2003, 03:35 PM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
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Quote:
Originally posted by mmormota
Take a look to this article:
Thanks, it was something. Can we get 97% efficiency That will be something. But thy guy used Halbach magnet array - I don't think it's in this flat CD-ROM motor. I guess it's just the iron outer ring (here we have metal losses again).
I don't understand the way he wired this motor. CD-ROM has 4 simple flat coils that I can understand. It would be very difficult, but possible to have two flat spiral winding on each pole. I mean the wire is going flat spirally from outside to inside and on the second layer from inside to outside. Using round 1mm wire, epoxy the whole coil and polish each surface about 0.25mm. This would reduce the air gap to the minimum on 10T pole.

I need to think a little more, how to put everything together without special tools.

In the meantime I'm building a database of CD-ROMs - what kind of motor is inside and how easy is to make a BL conversion of that. I have 21 CD-ROM types in there and it's growing.

RysiuM
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Old Dec 27, 2003, 05:14 AM
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Tokyo, Japan
Joined Nov 2002
858 Posts
Double cheese burger CD-ROM motor

Double stack stator can eat over 10A with high efficiency.
E-tec 10C continous high capacity Li-Po and Kokam 15C 1200mAh type, coming soon?!
That is why I made new Doppelwhopper.

Double 0.32mm dia. 17T, Y for 3S configuration.
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Old Dec 28, 2003, 11:42 PM
Registered User
Vacaville, Calif
Joined Jul 2003
98 Posts
rcflyr2,
tell me more about your lathe.
Was it about 200.00?

Did it include cutting tools?
Where did you buy it and where can you get accessoties for it..
Just what I may be looking for..

Thanks
Hook
lwciak@cableone.net
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Old Dec 29, 2003, 07:01 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,429 Posts
Hook,
Cutting tools are generally not included. A good source that specializes in these small lathes is
http://www.littlemachineshop.com/
Things you can get from them include cutting tools, quick change tool holders, collet sets, chucks, etc. Other general machining suppliers would be places like Penntool, McMasterCarr, etc. Items like drills in 1/64th increments and numbered drills are useful, end drills, small tail stock chucks, etc can be ordered from these sources.

But, this is kind of off topic. More info can be found in the workshop forum.

I have the longer version of this lathe and nice motor things can be machined on it.

Gordon
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Old Dec 29, 2003, 07:31 AM
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Edmonds Wa. (Seattle)
Joined Nov 2003
3,926 Posts
Well the little lathe who could!
This is my first project on the lathe, It is the smallest motor I have and all parts including the new mount weighs in at 10 grams
The new mount weighs 1.3 grams!
This motor has not been ran yet I was working on the longer shaft and the motor mount.
Next I will be taping the ends so I can bolt on the prop.
Hope you like it!
rcflyer2
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Old Dec 29, 2003, 07:32 AM
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Edmonds Wa. (Seattle)
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all together!
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