Efficiency governs power

[1BOHO]

http://www.infolytica.com/en/applica...%20Magnets.mp4


"The eddy current losses for each case are compared in the table. As the chart indicates, the losses decrease significantly as the segment count increases, whether it be by using circumferential, axial or a combination of the two segmentation methods."

[1BOHO]

https://www.unibw.de/rz/dokumente/ge...920168&fd=kein

https://dokumente.unibw.de/pub/bscw....20Gerling).pdf

https://www.unibw.de/rz/dokumente/ge...298514&fd=kein

[CHX2]

Hi ,
wy not showing the whole list of papers , https://www.unibw.de/eaa/forschung/v...y_of_jahr-2015 . So you can search all , but remember this is tecnical stand of the 1980 of the MagnetMotor company .

[1BOHO]

I have the book but as an IEEE member and not the author I don't have the appropriate permissions to post complete papers on a model forum.Did magnetmotor hold it all proprietary for 36 years as the most recent summarized I triple E papers were posted as radical and new by the team on the line?

And gosh who was running brushless motors in models in 1980 were you?

[1BOHO]

I was 9 years old in 1980 but it seems the first Brushless dc motors made the scene in 1962 when TG Wilson and IEEE member PH Trickey ( Duke University Durham, N.C.) unveiled what they called a dc machine with solid state commutation. Near the end of 1980 Robert E Lordo of POWERTEC industrial motors Rock Hill, S.C. unveiled a brushless dc motor that had 10 times the power of any earlier designs.

http://wanderlodgegurus.com/database...C%20motors.pdf
http://patents.justia.com/inventor/robert-e-lordo
http://www.powertecmotors.com/


When was the first time you saw one in any rc model of any kind?

[1BOHO]

"my first contact with a brushless motordesign was at AOA Gauting in 1981 when they designed a brushless axial oriented motordesign for the Leopard tank to turn the gun turret . Motor was designed with samarium cobalt magnets . Electronic was to complicated for me and transistors are much bigger as mosfets are in the early days . First brushless a saw in a modelairplane was a Aveox motor with hall sensors in 1993 i think by Norbert Hübner F5B plane. Then Kontronik and Plettenberg step in and Hans Lehner starts with the slotless designs and i invite him to go with sensorless controllers. My first brushless outrunner i build in 1994-5 for the 10 cell F5B class."

Happy Amps Christian

Perfectly ok if you would have posted this here as well. As a part of the history lesson.

I think I may have photos in my many folders of these pre sensorless logic based controllers that Hans was using.

[1BOHO]

Since you are here reading CHX2 What was the brand and type of machine shop tools you used to build your first outrunner? what kind of numbers did these machines hold? For the airgap as an example how did you ensure a consistent one for the entire axial length of the can? What measuring tools did you use to verify? what were the materials of the can what was the IPM and speed you used to cut it? What was the finish in microinches? What material was the stator made from? Did you build the stack?What was the process? How did you ensure equal spacing of the magnets and what was the tolerance max an minimums you tried to adhere to overall for the motor? Before the advent of CNC If you built one that you liked what jigs or fixtures did you make to give you easy repeatability? it seems material selection and the precision of the machining and assembly would all lead to a better more efficient motor. To theorize and draw up a nice machine is one thing but to manufacture it may be something different. Any tips you can offer would be a great help to all with aspirations I'm sure.

[CHX2]

Ok ,
first outrunner was lath on a Deckel lath basic with no automatic suport and a Deckel fp1 . I have all calipper for 10 and 1000 micron as i have learnd the job "Feinmechaniker " at the AOA Gauting company that produce the instruments for jetfighter Tornado and Alphajet and many other Sperry fly instruments . I have build some 4:1 oversized instruments for the Deutsches Museum München showcase to show people how this mechanical instruments worke. As this first motor was only a short ,fast and dirty look ,doe's the 12N14P system worke well for modelairplane it was only made with a stator from Bühlermotors out of normal,silicon steel M 280 and wind with sps winding system . Space between magnets by calipper precicion cut stirpes hold all magnetstrips äquidistant around . See photo of this motor ,this was the first high pole outrunnermotor using this system runing at 10 cutoff sanyo 1,5 Ah cells sucking from 80-120 amps belong to the folder propeller size . No jig and fixur needed ,this was a very easy to build motor and only a quick and dirty test ,no moore intension .But it fullfills a our hope and moore as it was lighter and had higher power ,better efficancy and runs cooler than the old brushed Plettenberg ,Astro and Keller motors as all the other brushed motors need a gear .Only one Plettenberg motor was there that could direct drive the same propeller but was moore than double the waight than the small outrunner .
Happy Amps Christian

[CHX2]

moore pic ,open motor.

[CHX2]

But for the first outrunner you need allso the pic of the first sensorless esc from me .

[CHX2]

see from one side the parallel double fets .

[CHX2]

But all this was nothing as i build the direct drive heicoptermotor 1996 out of cobalt iron stator plates electro wire corrosive cutting the 7 hundrets super thin plates that need spezial heat treatment in hydrogen so this plates come soft like paper . No stress has to reach the plates as they are very difficult to handle. Isolated by 1 micron and less ceramic balls giving the best isulation you can make for such highend material.i send one pack of this plates to R.Okon and his friend Herbert Kabiey destroyes them becaus of unable to handle such expensiv material.Was a big mistake to give this plates away.I got no thanks or anything other for this present.

Happy Amps Christian

[1BOHO]

Christian very nice post about the technical sides but please leave the personal stuff about Ralph out. No one here wants to hear it or cares and he hasn't said a solitary word here. Let it go.

That being said I have photos of that direct drive motor you speak of. And my SPS stators made from very thin hiperco50 plates comes soon Enuf it is very expensive and equally very intolerant of mishandling. The stack will be prepared and annealed by Polaris and the exact price can not be disclosed but the prototype motor will be well over 3000.00 usd in materials my machining and my design time.

My private message have been amended to receive PM only from contacts and the moderators so anything additionally you would like to say on a more personal note you can leave in my profile visitors message box or here in the public forum.

Thank you.

[1BOHO]

And so The IEEE and innovators in the US who listened take BLDC motor design and efficiency to a whole new level.




http://www.thingap.com/
ThinGap
2064 Eastman Avenue
Ventura, CA 93003

Get ready for the future in bldc outrunner model motor design in my eyes this is the now. A slot less outrunner with printed coils.

[Raptorapture]

Nice link and pic! It occurs to me that the tolerances required for the "thin gap" are going to place even more extreme tolerances on the shaft and support bearings. Would be interesting if someone did a secondary supporting rotational structure further out from the shaft given the space that's there now without an iron core stator. Let's say half way between the centre and the "bell". That would allow tighter control over the gap while reducing the demands on the bearing by distributing the accuracy across a bearing spanning a much larger circumference.

[1BOHO]

What are the actual tolerance numbers you speak of ? Thin gap is just a name it doesnt really speak to the actual dimensions or tolerances. Post the link. This motor is would be very easy to manufacture mechanically. 2d Cam modeling very simple.

[Raptorapture]

Based on the structure of their motors I assumed thin gap was referring either to the need or their achievement with respect to the gap between can and stator.

I'm really bad at drawing and don't use cad s/w so no plans to draw it up but I think I pretty much described my intention for enhancing the design. If the gap does not need the kind of tight tolerances I was imagining then the point is mute. If it does then having a guide that has a larger diameter than the shaft at centre will facilitate a more accurate and consequently thinner gap.

[1BOHO]

Their innovation lies in the use of the printed coils for higher power and torque density not "thin gaps" by name and ironless stators virtually eliminating torque ripple all creating very efficient and smooth running motors as compared to some of the more conventional designs. As far as structure they have no set mechanics as they offer many options some which seem pretty solid if they've already achieved ducted fans producing 400 plus pounds of static thrust but without a drawing or photo it would be very hard for anyone to conceive or build post facto designs.

[Raptorapture]

Very innovative! I can see how the torque just goes through the roof with this design. Perfect use for that. I assume the "stator" is along the outer edge of the fan? My bad then on the assumption the design allowed for a tighter tolerance in terms of gap.

[1BOHO]

According to my calculator and recorded motor constants. Good efficiency is possible with a well filled single layer with large coils.





Here is the single layer 700 MX Align tuned for an 1/8 scale hydroplane. 7 turns of 13 ga. in a skipped tooth parallel wye. 133% increase in copper cross sectional area over stock.
Rm .oo5 ohms
Kv 824
Io 3.27 amps @22.5 volts including radial fan load.
Weight 448.8 grams

Here it is on 12s in the FE boat cal.

ABC 1818 calculated as most efficient prop in its database for performance hydro @ 12s lipo 9800 mah

33,940 rpm
153 amps
Pin 6.394 kilowatts
Pout 6.125 kilowatts
Run time 3.85 minutes
Est speed 90.12 mph or 145.03408 km/h
Eff. 95.80 %

In the graph u can see the efficiency doesn't start to drop off till 268 amperes at that is apprx. 12kw and over 2ft/lbs of torque.


90.12 mph is really fast in the water for a 4 min oval boat over 6.9 Kg. The Preece value for two 1.828mm conductors is 398 amperes and it is a class h insulation so the motor I think can definitely pull 268 amperes for 10 seconds.