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Old Jan 11, 2004, 07:28 AM
Registered User
Edmonds Wa. (Seattle)
Joined Nov 2003
3,926 Posts
Hi,
I know you wraped it for tourq but! The prop is way to big, You need a smaller pitch on the prop as not to overload the motor.
It needs a 7x3 or a 6x3.
I got a 24 gramer to put out 10.1 oz thrust with a 7x3 at under 9amps and if I change the mags the amps will go down,
Glad she is not getting to hot now and a good selection of props for testing is a must.
Good luck
Little Screamers
Scott
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Old Jan 11, 2004, 09:57 AM
Jack of all trades!
Scoobyvroom's Avatar
Rockford, MN
Joined Jul 2003
450 Posts
MAn I am starting to get discouraged with RC Groups I posted two new threads not wanting to get off on other threads and no one has replyed to either but even after over 50 people viewed them on both.

Anyway hopefully someone will care in here...


I got this motor out of a Digital Research 2x Burner...
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Last edited by Scoobyvroom; Jan 11, 2004 at 10:01 AM.
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Old Jan 11, 2004, 10:00 AM
Jack of all trades!
Scoobyvroom's Avatar
Rockford, MN
Joined Jul 2003
450 Posts
O.k. I forgot to post the pic, can someone tell me if this would work in a geared setup it is pretty small from the other CD-rom motors I have pulled apart... But this one fits perfect in a 300C gearbox, even the holes line up... you can read most of my dim on the paper next to it...

Chris
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Old Jan 11, 2004, 10:39 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,790 Posts
Quote:
Originally posted by CrazEflyer
I have a cd-rom motor that i have converted, and it shuters at half throtle and it all so gets very hot. The cd-rom motor is a sony 56x with a thin gray magnet. I put 16 turns of 22 or 24 guage wire Y wind on it and instaled ball bearings. Do any of you know what i could do diffrent to fix it.
1- Drive your motor with a drill, measure the voltages between the star-point and the motor leads. They should be the same. If not you either have a short(s) or not all coils have the same number of windings.
2-Replace the original ring-magnet with Neodymium magnets. Lower Kv and higher Kt, higher efficiency and easier for the controller to get in sync with the motor.

Met vriendelijke groet Ron van Sommeren
diy outrunner brushless e-motor discussion.
Electric fly-in & lrk meet, June 27th, 2004, Nijmegen, the Netherlands.
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Old Jan 11, 2004, 10:44 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,790 Posts
Quote:
Originally posted by rysium
By giving stronger magnets you will have two things:
1 - when you have a stronger magnetic field on the rotor, you can have the same torque with less current on the stator = better efficiency
Not quite. By using stronger magnets you can lower the product of current and #windings to get the same torque (N*A). Lower the number of windings and you get space to use thicker wire, this lowers the coil's resistance and efficiency improves.
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Old Jan 11, 2004, 11:10 AM
Hi Wattage Electrics - Cool
Rad Racer's Avatar
Jordan, Minnesota
Joined Jan 2004
617 Posts
Quote:
O.k. I forgot to post the pic, can someone tell me if this would work in a geared setup it is pretty small from the other CD-rom motors I have pulled apart... But this one fits perfect in a 300C gearbox, even the holes line up... you can read most of my dim on the paper next to it...
Yeap, this motor will work in a geared setup. I am using a motor with very similar spec's. You can look at my previous post for details of my motor (post = "CD rom gear drive and ducted fan"). One difficulty maybe the pinion gear, mine needed to be drilled out to a 3mm press fit. If you have a lathe it's easy, otherwise you can try a drillpress and a vise.

The only change I made since I posted the spec's, is to change the magnets to the 5x5x1 N45's.... I highly recommend the change. I have been flying my gear motor in a Slow stick, it works great.

hope this helps,
Wayne
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Old Jan 12, 2004, 12:41 AM
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jason_ices's Avatar
MALAYSIA
Joined Aug 2003
237 Posts
my motor only can get wot with gws 0425, when i change to apc 4.2 X 4 it will miss fire at wot but at middle of throttle it spin fast ! Does any body know what happening?
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Old Jan 12, 2004, 08:11 AM
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JRW21's Avatar
Dunlap, Illinois, United States
Joined Aug 2003
320 Posts
You will need to retard the timing on your controller.
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Old Jan 12, 2004, 09:40 AM
Registered User
Joined Oct 2003
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Your magnets are a little weak sounds like.
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Old Jan 12, 2004, 10:12 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,790 Posts
Jason, I have two words for you
www.engconcepts.net
www.supermagnete.ch
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Old Jan 12, 2004, 10:25 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
1,714 Posts
Quote:
Originally posted by Matthew Cotten
Your magnets are a little weak sounds like.
That's right.

Let me add a little explanation. The rotating magnetic field from the rotor generates the voltage in the stator that is sensed by ESC (that's how the ESC knows the position of the rotor for the right timing). When magnets are weak the response is so weak, that it gets lost in the electric noise and can't be sensed by ESC any more.

Right answer: Stronger magnets in the rotor.

RysiuM
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Old Jan 12, 2004, 11:05 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,790 Posts
And it could be that your controller is at it's (2-magnetpole) rpm limit, commutationwise. Remember, for a 9pole/12magnet motor the ESC has to switch 6 times more often than for a 2-magnetpole motor. If your cd-rom motor runs at say 15.000 rpm, it is the equivalent of a 2-magnetpole motor running at 90.000rpm. Stronger magnets lower your rpm (and increase torque).
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Last edited by Ron van Sommeren; Jan 12, 2004 at 11:22 AM.
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Old Jan 12, 2004, 11:17 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
1,714 Posts
Quote:
Originally posted by Ron van Sommeren
If your cd-rom motor runnig at say 15.000 rpm, is the equivalent of a 2-magnetpole motor running at 90.000rpm. Stronger magnets lower your rpm.
When I was testing the max speed of one of my motors I run it without load to about 60k rpm (it sounded like a turbine ).
The controler is Phoenix 10.

RysiuM
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Old Jan 12, 2004, 08:51 PM
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Joined Mar 2001
2,625 Posts
A friend of mine gave me a bunch of cast off motors and drives. Here they are all lined up neatly:
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Old Jan 12, 2004, 08:53 PM
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Joined Mar 2001
2,625 Posts
Here is one I thought rather interesting. It turned out to have 24 stator poles and 16 magnets poles. Any hope for this one Ron?
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