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Old Dec 29, 2005, 05:41 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
Build Log
Large custom inrunner BL motor build, BFI 5628, parts from Applimotion INC.

First, I would like to point out that this is not a beginners project, It requires Lathe and Mill work.


I recently talked with someone at an industrial brushless motor design and manufactureing company (Applimotion Inc.) about purchaseing Stator material to make my own large outrunner brushless motors for use in RC planes or helicopters. Although they did not have any stator material for me they were interested in RC electric flight. They just so happened to have several motors that did not meet design specs for some medical device (A small cut in the insulation of one wire), but might be perfect for a large RC power plant. This is what I am now trying to build.

Applimotion only makes the stator and magnet assembly to be built into some electrical device. So now it is up to me to build a case and shaft for this new motor.

The specs given for this motor are:
OD: 2.2"
ID: 0.97"
Stator Length: 1.1"
Res: 0.12ohm
Ke: 4.7 V/Krpm (this is equivalent to 212 RPM/Volt)
Kt: 6.4 Oz-In/Amp
Number of magnet poles: 8
Number of Stator poles: 12
Max Voltage: 200V
Max Cuurent: 65Amps
Max recommended RPM: 6,000 (I was told that above 6K it will loose efficiency)

cuurently I plan on feeding it 18Volts and pull up to 35 amps for a total of about 630watts.

I am calling this the BFI 5628
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Old Dec 29, 2005, 05:47 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
If you would like to purchase one of these motor kits for your own build drop an E-mail to:

rob@applimotion.com

Be sure to put "Motors for my RC" in the subject line.

He charged me $65 for one set which includes the wound stator and the magnetized magnet tube. They do have a small gash in the insulation of one wire but it can easilly be repaired.

You could use your own magnets but Applimotion has used FEA programs to be sure that it is very efficient with the magnet supplied.

NOTE: he only had about 2 dozen of these reject motors
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Old Dec 29, 2005, 05:55 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
The Design

Here is the design I have so far.

It is recommended that you use some "Back Iron" behind the magnets (at least .125" thick). this Back iron will be attached to an 8mm shaft and i plan on using Skate bearings as the bearings.

I will make an aluminum housing. A simple tube with 2 aluminum end-pieces pressed, or bonded in.

I just got back from a local metal supply store and found some suitable aluminum tubing and bar stock for the case. The tube will be the first thing i make. I plan on gluing the stator into this aluminum tube.

Any suggestions are welcomed. I have built outrunners before, but no in-runners.
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Old Dec 29, 2005, 07:57 PM
Look what I did:D
plumb's Avatar
orlando,Fl
Joined Mar 2003
928 Posts
How much do they weigh? I may be interested in a statorless version... not quite a 2.2 incher, maby 1 1/4 would do.
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Old Dec 29, 2005, 09:26 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
I just finished machining the case...(boy it's nice to have a lathe in the garage).

The weight of the stator and wires is 11.5oz

Plumb,
I don't think anything that Applimotion makes is coreless. Your on your own there. I do remember seeing some build threads about that.
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Old Dec 30, 2005, 03:44 PM
Flying motor mount master
fly_boy99's Avatar
San Jose, California, United States
Joined Oct 2004
8,745 Posts
Wow this looks like some motor!!! Heck put this baby in a gearbox and go to the moon!!!

I might have to join you as I just got a lathe!!!

projects projects!!!
fb
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Old Dec 30, 2005, 05:24 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
with a KV of only 212 you might need to gear it up....

The axi 5330/24 has a similar kV (197) and they suggest a 23" or 21" prop direct drive.
http://www.modelmotors.cz/index.php?...495%20-%20652g)


Lathes are fun, but you might find your self spending more money on tools, than on planes....
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Old Dec 30, 2005, 10:12 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
well after stalling the lathe about 4 or 5 times (during cutoff), i finally got the lathe work done on one end cap. It took alot longer than I expected. (This size stuff really could use a larger, more powerfull lathe)

I will put the lightening holes and mounting threads in manually using a drill press.
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Old Dec 31, 2005, 11:42 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
I finished the lathe work on the other end cap. But since it is new years and all (----Happy New Years---) I can't use my friends drill press, since he is a t a party.

So I rigged up my own drill press on the lathe. I Marked all the holes by hand using 2 rings i etched into the face of the endcap when it was still on the lathe. after marking the holes i mounted it to the lathe and then clamped it in place and drilled and tapped the holes. I just finished on endcap, but will probably call it a night and finish the other endcap tomorrow.

I also cut the shaft to length and lightly filed it so that the bearings would not be too tight.
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Old Jan 01, 2006, 01:34 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
Well i finished the other endcap. I even did a little wet sanding to get it looking nice.

I still need to make the Back Iron and then glue and press it all together. I might actually get it spinning by tomorrow.

I'm pleasantly surprised at how easy it is to make an inrunner compared to the Outrunners. there is not as much precision needed for the inrunners as there are less rotating parts to get perfect.
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Old Jan 01, 2006, 04:01 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
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just finished the back-iron. I drilled the hole a little big so i didn't get a press fit but that's what loctite is for.

Tomorrow I'll start glueing everything together.
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Old Jan 01, 2006, 08:38 PM
Flying motor mount master
fly_boy99's Avatar
San Jose, California, United States
Joined Oct 2004
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This lathe is a four chuck lathe and it's pretty much all setup but I know what you mean about buying more and more tools for it.

Looks good... hope she'll hold up for a 23" prop at a 30A load!!!

Where did you find a 8mm shaft? I assume you will use two backplates...

As for the tab you will be using to keep the stator in a single place while the magnet spins the shaft at < 6k rpm right? Maybe you can elaborate here...

Quote:
Originally Posted by dogon1013
with a KV of only 212 you might need to gear it up....

The axi 5330/24 has a similar kV (197) and they suggest a 23" or 21" prop direct drive.
http://www.modelmotors.cz/index.php?...495%20-%20652g)


Lathes are fun, but you might find your self spending more money on tools, than on planes....
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Old Jan 01, 2006, 11:49 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
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The 8mm shaft came from a local surplus store here in Orlando called skycraft surplus.
It was just a generic 8mm shaft, relativelly soft material. I will probably order a stronger shaft for the next one.

No tab to hold the stators on. I'm just gonna loctite the stator to the tube. It should hold fine, there is alot of surface area.

Yes the 2 endplates are identical, they will be pressed into place with a little loctite as well.

I don't think a 23" prop is reasonable. I'll start small, 12" to 14" maybe.

I have a .60 Lancair that this should power well.
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Old Jan 02, 2006, 09:33 AM
Master of 1 point landing
Naperville, IL
Joined Jul 2005
2,841 Posts
Quote:
Originally Posted by dogon1013
The 8mm shaft came from a local surplus store here in Orlando called skycraft surplus.
It was just a generic 8mm shaft, relativelly soft material. I will probably order a stronger shaft for the next one.

No tab to hold the stators on. I'm just gonna loctite the stator to the tube. It should hold fine, there is alot of surface area.

Yes the 2 endplates are identical, they will be pressed into place with a little loctite as well.

I don't think a 23" prop is reasonable. I'll start small, 12" to 14" maybe.

I have a .60 Lancair that this should power well.

Drill blanks make excellent shafts - look in mcmaster.com and search for drill blanks. A 12" prop on that beast is like putting and EDF on a Airbus. At the above stated KV, you gonna need a BIG prop (or gear it up 6:1)
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Old Jan 02, 2006, 12:44 PM
Watts Rule, Glows Drool
dogon1013's Avatar
orlando, FL
Joined Mar 2003
3,197 Posts
yea, i'm sure your right. I may need to up the voltage. or maybe just gear it up.
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