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Old Sep 09, 2003, 07:43 AM
Registered User
Tokyo, Japan
Joined Nov 2002
866 Posts
Replace the magnets

You can buy 5mmx5mmx1mmt, 12 of neodyium magnets set from NipponDave with this sample photo CD-ROM as same as mine.

http://www.aircraft-world.com/
(not shown on the Web. Ask them by e-mail)

You must consider the clearance between stator and magnets. Therefore, I fired out the original neodyium plastic ring magnet.
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Old Sep 09, 2003, 07:46 AM
Registered User
Tokyo, Japan
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Make the hyper magnet ring.

I feel the magnet price is not bad from NipponDave. Japanese price is about 30 cents each.
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Last edited by Takao Shimizu; Sep 09, 2003 at 08:18 AM.
Old Sep 09, 2003, 08:08 AM
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Tokyo, Japan
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magnets polarity

See the arrangements of magnet plates as shown.
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Old Sep 09, 2003, 08:28 AM
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Chiba, Japan
Joined Jan 2002
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Larger prop

Quote:
Originally posted by DNA

Do I need to rewind it with smaller wire to get the amps down? I would prefer to use something like a 9x6 prop.
Hi DNA,

26 gauge is definitely too hot for large prop. Maybe good for small one like 5x5. I am testing remagnetted bell with original wind (0.2mm, 32 gauge 66T) with delta connection. It rotates GWS Hyper 8x4 or 9x5 at less than 20W or so. 0.3mm (28~29 gauge?) will drive nearly 40W. I need to fly it to test more. Perhaps on SlowStick? Challenge is to find acceptable winding/configuration for the controller. My MGM Compro TMM 1210-3s is ok but (old) Phoenix-10 tends to stall early and need stronger magnet. I need further testing on them.

Hope this helps.

Satoru
Code:
0.2 mm 66T Delta, old Kokam 1020 2s			
GWS Hyper 8x4		7.03V	1.92A	13.50W	5,100rpm
GWS Hyper 9x5		6.65V	2.42A	16.10W	3,780rpm
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Last edited by ssatoru; Sep 09, 2003 at 10:18 AM.
Old Sep 11, 2003, 10:20 AM
Unicorn
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(Cordova)Memphis, TN
Joined Jul 2002
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Seagate HD

Guys,

I took home 4 dead HD's from work last night and set to work. The motors in these are smaller than CD-ROMs and encased in AL. Not knowing what I was working with, I went medieval on the first one. I cut it in half The second one was cake to open

Take a look. I'll try to take some measurements, but best-guessing I'd say 3/4" diameter by 3/8" tall (around 23-25 plates but hard to count ) Ball bearings on either end. The second one is not as tall (laying on it's side in the picture). Also, unwinding the first stator, I counted 41 turns (or thereabouts).

Jay

Edit: Not shown is the upper ball bearing (RIP)
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Last edited by Jay C; Sep 11, 2003 at 10:32 AM.
Old Sep 11, 2003, 10:22 AM
Unicorn
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(Cordova)Memphis, TN
Joined Jul 2002
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In the first shot, you can see that I cut through the inference ring and neodymium magnet. In this shot, you can see how they are encased in AL.
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Old Sep 11, 2003, 10:24 AM
Unicorn
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Joined Jul 2002
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And finally (sorry for the fuzzy pic), this one shows the 3 connections (it was Wye connected) to the windings. There is a keyhole slot in the stator shaft to accept the wires.
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Old Sep 11, 2003, 10:29 AM
Unicorn
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BTW, the yellow squares on the cutting mat are 1" apart for your reference. I plan to somhow coax the stator off the shaft so I can wind it as a delta and put it on the CD-ROM shaft I have. This will gime me the clearance I need to put in some neodymium magnets in place of the rubberized one. Any suggestion on the best way to remove the stator? Also, I was less than gentle removing the old windings and removed some of the "paint" from the top. What is a good replacement?

Thanks,
Jay
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Old Sep 13, 2003, 09:54 AM
Unicorn
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(Cordova)Memphis, TN
Joined Jul 2002
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Progress:

I have received the MGM 18+3ph BL controller (thanks Mike) and mated a 20mm stator to a 26mm bell. Next step is to order magnets and go buy magnet wire. Using cad, you can see that I am able to use 12 5mm x 2mm (either square or round) magnets and still have a .5mm gap. I have been reading the LRK message group for the past week, concentrating on the theory and explaination posts. Once I reach the end (I'm in the July 2003 posts) I will start logging successful posts that specify the number of turns they used (including this one). My goal is to replace my SP400 DD with a white gunther prop on my wing.

The magnets will come from http://www.engconcepts.net as he has the N45 in the sizes I want:
N45 5mmsq x 2mm 20 @ $4.00
N45 5mmdia x 2mm 20 @ $4.00
N40 5mmsq x 1mm 20 @ $3.00
Shipping = $6

Suggestions are welcomed.

Jay
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Last edited by Jay C; Sep 13, 2003 at 06:15 PM.
Old Sep 13, 2003, 11:18 AM
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Chiba, Japan
Joined Jan 2002
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Quote:
Originally posted by Jay C

The magnets will come from http://www.engconcepts.net as he has the N45 in the sizes I want:
N45 5mmsq x 2mm 20 @ $4.00
N45 5mmdia x 2mm 20 @ $4.00
N40 5mmsq x 1mm 20 @ $3.00
Shipping = $6

Jay
Hi Jay C,

I'm afraid 2mm magnet may be too thick and will not fit. (Unless you are lucky to find a CDROM motor with large gap.) I tried 5mm dia x 1.5mm first but could not fit them. Good luck!

Satoru
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Old Sep 13, 2003, 11:19 AM
Watts your motivation
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San Bernardino, CA
Joined Aug 2003
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I see your already going to by from George (engconcepts), so I won't change anything. I just have to say I am thoroughly impressed by George and his promptness. I e-mailed him yesterday, and after paypaling him at around midnight, he responded and said they will go out today!!

As for magnet wire, I am having trouble finding any source other than RadioShacks "assortment". I am looking for .50mm or slightly larger. If I cannot find any readily, I will just wind multiple strands of wire to increase the copper.

Jay after reading all the posts (I'm on #745) Do you know if you wind multiple strands by twisting them together FIRST, then wrappng them on the stator? Or just wind all of the first strand on one arm, then the next strand on the same arm? Or even jsut wind them simultaniously side by side?
Thanks,

Justin
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Old Sep 13, 2003, 11:39 AM
Unicorn
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(Cordova)Memphis, TN
Joined Jul 2002
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Quote:
I'm afraid 2mm magnet may be too thick and will not fit. (Unless you are lucky to find a CDROM motor with large gap.) I tried 5mm dia x 1.5mm first but could not fit them. Good luck!
Satoru, I have a 3mm gap all around the stator to the shell (I mixed and matched stators and bells from two drives). The autocad drawing shows that I will have plenty of clearance...so your statement is somewhat confusing to me?

Quote:
Jay after reading all the posts (I'm on #745) Do you know if you wind multiple strands by twisting them together FIRST, then wrappng them on the stator? Or just wind all of the first strand on one arm, then the next strand on the same arm? Or even just wind them simultaniously side by side?
Justin, according to the posts I've read, you want as little space between the copper as possible. Therefore, everyone recommends that you wind them side by side without twisting and at the same time as if they were one.

Jay
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Last edited by Jay C; Sep 13, 2003 at 12:47 PM.
Old Sep 13, 2003, 11:58 AM
Registered User
Miami, FL USA
Joined Feb 2000
89 Posts
Magnet Wire

A good selection of magnet wire is available from Carr- McMasters.
They have 4 or 5 warehouses around the USA and prices are
reasonable, but lots may be more than you want. It may be what
you need, I have used for CDROM motors with good results.
PS they have many metric and SAE fasteners, good luck, Cecil
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Old Sep 13, 2003, 12:00 PM
Unicorn
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(Cordova)Memphis, TN
Joined Jul 2002
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A picture of the unwound stator and the soon to be removed plastic neo magnet. Again, the bell is 26mm, the neo ring 1mm, and the stator 20mm. BTW, where they is no "green" insulation on the top plat, I put a thick layer of clear nail polish.

Jay
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Last edited by Jay C; Sep 13, 2003 at 12:03 PM.
Old Sep 13, 2003, 12:20 PM
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Chiba, Japan
Joined Jan 2002
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Gap

Hi Jay,

Wow, lots of space. Looks like a very good motor. Sorry for confusion.

Yes, I wind double wire without twisting. It seems I need to wind wires one by one to have the best result but I just wound two wire together.

Satoru
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