12 kw rc motor

Electric Motors and Controllers
toolman2
1 kW
1 kW
Posts: 419
Joined: Feb 23, 2010 9:34 pm

Re: 12 kw rc motor

Post by toolman2 » Sep 07, 2013 9:35 am

bearing wrote: Pole count will not increase velocity. Magnetic field (in air gap, I assume) should not change. Length does not change. So the induced voltage/kv should not change. But this formula is maybe only for coreless motors?
-it doesnt change velocity, but more magnets mean a faster rate of change of flux in the teeth, and a higher number of cycles per rotation.

arlo that new controller you speak of runs just 10kpwm etc and may not even run hubbies to enough speed.

you can buy a controller for $489 that will get you well over 11kw shaft output from, it just not that much of a drama, accept for sevcons that have no speed. and arlo i thought your controller was meant to be cheaper alternative to an equivalent kw kelly?

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 07, 2013 9:48 am

Here's someone who did a test: http://www.helifreak.com/showthread.php?t=475358

Aslo, see Bruce Abbott's reply in this thread at RC Groups:
http://www.rcgroups.com/forums/showthread.php?t=1377493

User avatar
Arlo1
100 GW
100 GW
Posts: 8538
Joined: Apr 26, 2009 10:36 pm
Location: Nanaimo BC Canada
Contact:

Re: 12 kw rc motor

Post by Arlo1 » Sep 07, 2013 10:39 am

toolman2 wrote:you can buy a controller for $489 that will get you well over 11kw shaft output from, it just not that much of a drama, accept for sevcons that have no speed. and arlo i thought your controller was meant to be cheaper alternative to an equivalent kw kelly?
What controller is it for 489? 11 kw is not bad. Is this the one Splinter got 7hp at the wheel from?
Mine is better with more fetures and in the future more power but I can not make it cheaper yet.
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

User avatar
Arlo1
100 GW
100 GW
Posts: 8538
Joined: Apr 26, 2009 10:36 pm
Location: Nanaimo BC Canada
Contact:

Re: 12 kw rc motor

Post by Arlo1 » Sep 07, 2013 10:54 am

Has anyone played with GM controllers yet? http://www.goldenmotor.com/
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

User avatar
Arlo1
100 GW
100 GW
Posts: 8538
Joined: Apr 26, 2009 10:36 pm
Location: Nanaimo BC Canada
Contact:

Re: 12 kw rc motor

Post by Arlo1 » Sep 07, 2013 12:31 pm

Haha called golden motor canada and he doesnt even know what PWM frequency meens.
My Leaf motor controller build. viewtopic.php?f=30&t=63982&p=963227#p963227
My YSR build http://www.youtube.com/watch?v=BRo8r5g4NBg
RC and most types of Lithium batteries you MUST know your individual cell voltages charging and discharging.
Don't keep them were you cant afford smoke or fire!
Never above 4.2v never below 2.7v EVER!!!
HI power controller design. Game Changer
http://www.undergroundelectrics.ca/

John in CR
100 GW
100 GW
Posts: 13909
Joined: May 20, 2008 12:58 am
Location: Paradise

Re: 12 kw rc motor

Post by John in CR » Sep 07, 2013 9:07 pm

toolman2 wrote:...you can buy a controller for $489 that will get you well over 11kw shaft output from...
Why spend so much? I can get more than 11kw out with less than $200 in controller cost, and I tested it for 9 months to prove durability. You can't go to the extremes of low cost, because most around here aren't comfortable without spending more money.

toolman2
1 kW
1 kW
Posts: 419
Joined: Feb 23, 2010 9:34 pm

Re: 12 kw rc motor

Post by toolman2 » Sep 08, 2013 12:32 am

John in CR wrote:
toolman2 wrote:...you can buy a controller for $489 that will get you well over 11kw shaft output from...
Why spend so much? I can get more than 11kw out with less than $200 in controller cost, and I tested it for 9 months to prove durability. You can't go to the extremes of low cost, because most around here aren't comfortable without spending more money.
no john, you are confusing your peak power consumption figure from the ca into massive heavy hub motor, with actual measured output at the tire using a dyno, they are different. :wink:
please dont bother reminding us that its verified cos you checked the motors side plate temp, with your finger. :roll:

but to answer your question anyway, its worth it for us to have good smooth torque throttle, 33khz pwm, super high erpm, heaps of pages of settings to tune and get good behavior from a very light and wound up rc motor. -i used a 24fet for a bit and it worked but was not very useable, im not keen for a greentime $58 special for this motor, but sure give it a try it may work.

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 12:53 am

Attached are two sets of simulations. First set is Colossus with 16p and 32p in no load and load simulations (free materials). They both show about the same torque. But the teeth have very high flux density with 16p, so it would never work in reality.

Second set is a 12t 8p/16p machine I made with really thick teeth, just to be able to run with true materials without getting into saturation with 8p. I ran no load and load simulations with free materials, and then load simulations with true materials (all I could afford, now I'm out of credits, lol). They all show about the same torque, although the 12t8p shows a little bit less, which I think is because there are some spots of saturation. But it may simply be in the margin of errors.

My results shows that pole count does not change kt. However, if the iron is close to saturation, then you may gain some kt by increasing pole count, I think.
Attachments
colossus-16p-100a-free.pdf
(461.18 KiB) Downloaded 81 times
colossus-32p-100a-free.pdf
(519.18 KiB) Downloaded 62 times
outrun-127mm-12t8p-6000rpm-100a-free.pdf
(795.24 KiB) Downloaded 51 times
outrun-127mm-12t16p-6000rpm-100a-free.pdf
(850.74 KiB) Downloaded 29 times
outrun-127mm-12t8p-6000rpm-100a.pdf
(454.39 KiB) Downloaded 43 times
outrun-127mm-12t16p-6000rpm-100a.pdf
(447.65 KiB) Downloaded 54 times

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 1:07 am

So, the 32p version requires a smaller core cross-section and therefore reduced the copper losses.... :)

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 1:09 am

Probably, but then you will saturate the teeth earlier when running with load.

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 1:15 am

bearing wrote:Probably, but then you will saturate the teeth earlier when running with load.
No more than you will with the 16p version, though....

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 1:20 am

Yes, that's right. But what I meant is that I think that if you do that, reduce tooth width, then you will get a smaller "working range" of the motor. It will become more of a low rpm, low torque motor, low loss motor.

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 1:24 am

It's really difficult to get a meaningful comparison by changing the pole count whilst keeping everything else the same. I think we've learnt that much!

toolman2
1 kW
1 kW
Posts: 419
Joined: Feb 23, 2010 9:34 pm

Re: 12 kw rc motor

Post by toolman2 » Sep 11, 2013 2:03 am

bearing wrote: My results shows that pole count does not change kt. However, if the iron is close to saturation, then you may gain some kt by increasing pole count, I think.
thanks bearing,
so wouldn't that mean theres no or very little torque advantage from higher pole count?
that seems at odds with even the rc groups findings and the hacker f3A motors change from 28 mag to 20 reducing max prop driving ability.
that would mean kv does not change either? -dunno.

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 2:13 am

Miles wrote:It's really difficult to get a meaningful comparison by changing the pole count whilst keeping everything else the same. I think we've learnt that much!
Ah, OK, now I see what you were saying before. More poles doesn't mean higher kt by itself. But it means that you can change the stator to get a lower weight, or smaller dimensions, or a higher proportion of copper, and so on. Which means you can get a higher kt with the same copper losses, if you wish. Yes thats true.

The start of this discussion however, was that I thought that changing to a rotor with more poles would create proportionally higher kt. And that is false. That was also what we thought in another thread prior to that, if I remember correct.
Last edited by bearing on Sep 11, 2013 2:38 am, edited 1 time in total.

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 2:19 am

toolman2 wrote:so wouldn't that mean theres no or very little torque advantage from higher pole count?
that seems at odds with even the rc groups findings and the hacker f3A motors change from 28 mag to 20 reducing max prop driving ability.
that would mean kv does not change either? -dunno.
I'm not sure, but I think that if the stator was designed for 28p, the teeth will get closer to saturation with 20p, which probably changes kt/kv for the worse.

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 3:05 am

Playing with Emetor is really addicitve :shock: I've been doing some loaded sims with 24t 28p. It works ok in linear mode.

toolman2
1 kW
1 kW
Posts: 419
Joined: Feb 23, 2010 9:34 pm

Re: 12 kw rc motor

Post by toolman2 » Sep 11, 2013 3:38 am

bearing wrote:
Miles wrote:It's really difficult to get a meaningful comparison by changing the pole count whilst keeping everything else the same. I think we've learnt that much!
Ah, OK, now I see what you were saying before. More poles doesn't mean higher kt by itself. But it means that you can change the stator to get a lower weight, or smaller dimensions, or a higher proportion of copper, and so on. Which means you can get a higher kt with the same copper losses, if you wish. Yes thats true.
gotcha, thanks that answers my question too.
just be careful guys, one of you is going to OD real bad on Emetor. :)

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 4:33 am

Miles wrote:Playing with Emetor is really addicitve :shock: I've been doing some loaded sims with 24t 28p. It works ok in linear mode.
Oh, It works now?

I noticed this morning that the "help pictures" when choosing parallel tooth, parallel slots etc are gone, so maybe the code was updated tonight.

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 4:44 am

It worked ok for me, in the free simulation version.

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 4:47 am

The reason I bought credits in the first place was that I thought that I needed them to be able to run the load sim on the Colossus. But it failed with true materials as well.

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 4:51 am

Looks like like it's been updated, then. Stephan seems to be really commited to this.

bearing
10 kW
10 kW
Posts: 638
Joined: Dec 24, 2008 2:14 am

Re: 12 kw rc motor

Post by bearing » Sep 11, 2013 5:02 am

The 24t28p load simulation seems to be very heavy though. Mine has been running for over 10 minutes now. We are going to overload his machine :( :D

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 5:04 am

Hehe... Mine only took a couple of minutes. Another advantage of small motors :mrgreen:

User avatar
Miles
100 GW
100 GW
Posts: 11436
Joined: Mar 16, 2007 4:15 pm
Location: London UK

Re: 12 kw rc motor

Post by Miles » Sep 11, 2013 5:37 am

Not sure why your simulations are taking longer than mine..... Just timed the latest one - 95 seconds

Post Reply