|Jan 26, 2004, 03:07 PM|
Re: 3 motors to rewind...
1- I've had good success with 28 ga wire in delta and star winding patterns. Having two similar motors, you could try both and compare the results with various props.
2- I've done a double stacked motor with a modified speed 280 bell, with two rows of 5x5x1. Glue one row first and let it dry. Be careful to maintain matching polarity on the second row
3- Go LRK: http://www.torcman.de/peterslrk/Wickel_arten_eng.html
|Jan 26, 2004, 07:31 PM|
Joined Mar 2001
The stator was too big to fit in the bell with 6 x 3 x 1.5mm N45s, so I made a mandrel for my Dremel from a 3mm CD-ROM laser tray guide and an MPJ 3mm prop adapter. I spun the stator in the Dremel, using a sanding block with 150 grit paper to sloooooowly shave the stator until it fit with < 0.5mm clearance all around.
|Jan 27, 2004, 02:52 PM|
Tucson Avra Valley, Arizona, United States
Joined Nov 2003
Ok, probably asked many times but this thread is so long that Im just going to ask again. What type of glue is used to secure the magnets in the bell? I have my magnets ready.. Thanks
|Jan 27, 2004, 03:00 PM|
|Jan 28, 2004, 10:16 AM|
Links to rewind AirCraft motor
Let me try to summarise rough steps. 900 messages of 'One hour CD_ROM motor construction' in a message.
1, Remove bell from motor
Open the end to remove stopper from shaft in any way.
2, Remove stator from mount
The brass stator mount is tightly pushed to stator and iron motor mount. Hammer it out.
Unwind removed stator, rewind as the following. I suggest to start with 0.3 mm 39T or 0.35mm 29T or so.
Connect to star. Delta draws 1.7 times more current.
Wire to your ESC with proper connector.
You can try to spin the motor at this stage. It is recommended to remagnet for better efficiency and stability.
4, Remove original ring magnet from bell
The ring magnet is glued to the bell metal.
or crack it
5, Glue 5x5x1 mm magnet to the bell
12 magnet in NSNS... order. Use CA.
6, Rebuild motor
You need to prepare motor mount. See below for an idea.
Put stator and bell to original brass stator mount. Note we do use any stopper for the shaft. Magnet force will keep it in place.
Use your idea mount prop. Mr. Shimizu use 5 mm plastic nut and works great with APC prop. I replaced original shaft with GWS IPS/EPS shaft as attached.
|Jan 28, 2004, 11:30 AM|
Re: Links to rewind AirCraft motor
It was OK from 2 lipos (static thrust is about 7.5oz).
|Jan 28, 2004, 12:02 PM|
|Jan 28, 2004, 01:04 PM|
I would love to see a short clip of the pilots thumbs (or fingers depending on the way they work the Radio Sticks) while doing some of thos rolling harrier circles.
That was cool
|Jan 28, 2004, 02:18 PM|
Joined Mar 2001
Re: Links to rewind AirCraft motor
|Jan 28, 2004, 03:00 PM|
I measured the same stator with two slightly different bells.
Stator: 18 mm diameter, 5,5mm length.
Bells: both machined low carbon steel, 12 pcs 5*5*1,5mm N45 magnets.
stator 1: 0,5 mm air gap
stator 2: 0,25 mm air gap
(I learnt to believe in the accuracy of a precision lathe...)
The measured parameters are improved a lot with the smaller airgap:
The Rm and Io is almost the same, but Kv lowered from 1740 to 1470. You may think that's not a big deal, but it is!!!
The Rm is the same, so if I modify the motor with lower turn number, thicker wire to get the same Kv, Rm will be about (1470/1740)^2*1,167= 0,83 ohm.
It means more then 30% less copper loss, that is a big improvement in efficiency.
This result clearly shows, that we have to keep the airgap as low as possible. Unfortunately it needs a more accurate bell and better bearings.
|Jan 28, 2004, 04:28 PM|
But I noticed you have over 1 ohm resistanc. It's a lot. Imagine you put 5Amp through, the power poss in the copper will be I^2*R that is 5 * 5 *1 = 25W. That's the total power I'm putting throuh my motor.
In my motor, and I used 26G wire 24 turn, using 0.4m per pole, so I used total 1.2m per phase. In delta connection my Rm = 0.08 ohm. Now if I put 5 amps throuht I'm loosing 2W in copper (and over 10W in iron ).
B.T.W. I gave my plane with Razor300 to my son, and I'm flying exclusivly other one with CD-ROM motor in board. Powered by 3s1p 700 LiPo I have 12-15 minuts doing torque roll, full speed snaps and rolls, waterfalls, climbing flat spins (straight and inverted) and so on. It's my personal 3D trainer - much better than any flight simulator. Anyway, after over 12 minutes of such practice I can notice, that it doesn't pull from torque roll as hard as it should. It's my cue to land. Battery usually is draind over 80% as it takes around 600mAh on charger(out of 700 capacity).
I will post some videos soon.
For now here is a picture:
|Jan 28, 2004, 05:56 PM|
Joined Mar 2002
rcall (or ne1) how much does the taig lathe ...
is it portable enough to haul back and forth between a table top and a closet on a daily basis?
my space is limited (no basements here in texas) so i would need it to go back into a closet quite frequently.
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