Magnet dimensions

[Serum]

Not that i am aware of Daniel..

Say, what is your experience between the 9920 and the micro12020?

Thanks papa.. Enough for the whole family..

[GriffinRU]

Originally posted by Serum
Well....

the 15 watts won't heat up the copper, but the magnet right? i thought we were talking about magnets?

that is what i am beginning to think as well..

Who gave you this information on the 1 percent gain in efficiency?

Like Mike and I said before, it is about the efficiency in the partial load, somehow you don't seem to understand.

You don't seem to understand what this is about. 1300 watts of 30A is impossible with that 1930/8.

I don't want a needless discussion about this, but please stop spreading this inaccurate information like it's a scientific funded fact.

Now can we please get back on topic?

Ok, I will stop here...

But I did not ignore information about partial load, it just not relative in our case. As I mentioned earlier 1% loss (data from EE lab, modeling, publications…) happens when magnet flux and phases flux mismatch. That only happens under very rare occasions (accelerations, braking, timing…) which for in-runner type motor even less possible.

But where Eddy current losses would be important is in windings, especially the one with core. As you know losses would be driven by RPM and switching frequency.

And as far as topic was about magnets, I thought it would be helpful to lit some light on this dark territory.

Artur

[coolhandcountry]

Well now. I am not sure about all that is said here. I will say one thing. I like the lehner motors. They seem to be better than the others that I have ran. I am not sure if it is the segmented magnets or the difference in the windings they put in case. What really matters here is that the motor you run move the truck around fast enough to make you happy. :) I don't sweat it if it runs 89% or 93% efficent. If the truck is what I want and the motor is pushing it there. I am happy. As for difference in windings between the xl2000 and a lehner 1930 t10. There is a difference. The magnets are different. Are they both nice motors. YES! Well I said my peace. Thanks!

[GriffinRU]

Originally posted by coolhandcountry
Well now. I am not sure about all that is said here. I will say one thing. I like the lehner motors. They seem to be better than the others that I have ran. I am not sure if it is the segmented magnets or the difference in the windings they put in case. What really matters here is that the motor you run move the truck around fast enough to make you happy. :) I don't sweat it if it runs 89% or 93% efficent. If the truck is what I want and the motor is pushing it there. I am happy. As for difference in windings between the xl2000 and a lehner 1930 t10. There is a difference. The magnets are different. Are they both nice motors. YES! Well I said my peace. Thanks!

That's exactly what I want to hear...
All the time Lehner motors operates in high efficiency, is it because magnets probably not.
But definetily overall design sounds to be the winner.

Can we do the same with others motors, I think yes we can. We might not get to the low 90, but we should own middle/high 80's.
And temp should be acceptable.

Artur

[RC-Monster Mike]

My truck is my dyno, Artur. Along with my temp gun(or my fingers in some cases!). I've tried many setups and systems in many vehicles and I know what I know based on this experience. I have toasted my fair share of motors and controllers as I progressed along the learning curve, but it has taught me some general rules/findings. I try to apply these findings myself, as well as guide others with this experience.
It is the greater RANGE of high efficiency achieved with the segmented magnets (higher efficiency over a greater range of rpms/amps/throttle input) more so than just the overall stated efficiency(which I already mentioned is typically stated at a specific rpm and amp draw value). You keep mentioning the 1%, but this is assumed PEAK efficiency, which happens at a very finite rpm/voltage/amperage vs. over w range of efficiency values at varying rpms/amps/voltage etc.. While the PEAK efficiency values are indeed very similar from segmented to non-segmented magnets, the RANGE of high efficiency will surely show a much larger difference(and we use our motors over a wide range and therefore experience much greater than a 1% gain).
Also, I did not state that the posted values were meaningless - just that their meaning is not related to this discussion. The numbers have meaning for sure(and the stated amps for the basic and basic xl series is indeed the value of their peak efficiency, however,the 30 amp value posted for the entire RANGE of 1930 motor winds is simply jibberish-each wind has its own specs in relation to these values). Also, these stated amps are not indicitive of 1300 watt output, either. For the basic series, it is simply the amp value at which peak efficiency occurred(and without the voltage and rpm values along with this info, not much can actually be taken from it quite frankly).
I think I am starting to repeat myself here. :)
Interesting discussion, though. Glad we could enjoy some popcorn during the course of it(though I wish my popcorn had more butter!). :)

[Serum]

is it because magnets probably not.

Best way to get accurate numbers on this, is by getting a tempgun and run the motor with a segmented rotor and a non segmented rotor. measuring the temps will tell for sure.

I will run big motors, with a lower KV at higher voltages.

I like to do speedruns, (100 percent WOT) so the partial load doesn't tickle me too much either. but when you need a big motor (such as a 2250-2280 size) their are not much other options than the lehners either..

I had a bigmaxximum (plettenberg) which was less smooth and IMO less powerfull than the feigao 7XL. (for a 1/3rd of the price)

I don't think good motors need to be expensive.

It sounds quite logical to me, that segmented magnets are better, otherwise the high end motor producers wouldn't use them anyway. It needs to be of some use doesn't it? And that 1% better would be at complete wot, the numbers differ on partial load. (better than a non segmented period)

[RC-Monster Mike]

Originally posted by GriffinRU
That's exactly what I want to hear...
All the time Lehner motors operates in high efficiency, is it because magnets probably not.
But definetily overall design sounds to be the winner.

Can we do the same with others motors, I think yes we can. We might not get to the low 90, but we should own middle/high 80's.
And temp should be acceptable.

Artur

Yes, the windings ALSO play a role here. The Lehner equivilent of a Feigao "s" motor(similar size and Kv) will also run cooler and longer than the Feigao, likely due to superior WINDING technology.
The Lehner basic xl and 1930 series, however, share the same winding technology, so it is pretty reasonable to assume the gain experienced from the 19 series motor is due to superior MAGNET technology(segmented construction-they obviously have the technology as they are the same company). I think I said this already, though. :)

[GriffinRU]

1% is only for magnet.
While motor Total efficiency from min to max RPM varies from 0-100%. So if in our best range this variation only 10-20% (way lower then magnet contribution) then motor runs cool. But if it is 40% spread then we are in trouble.
I do accept yours and everybody’s input as good and real data. And always accept fact that math on paper stays on paper, but real world is real. But if we start talking about high-end stuff, let’s be familiar and try to understand what we can feel and what we can measure.
One thing which I mentioned earlier but somehow it slipped away, utilizing segmented magnets allow reduce air gap with less penalty in Eddy Current losses. And that’s helps achieve efficiency in low and middle range.
And you correct 100% about efficiency sensitivity of Hacker/Feigao motors to particular RPM based on Kv.

Artur

[Papa]

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[Serum]

Artur, I thought you meant in the earlier post that a bigger airgap (Increasing) gave less eddy currents? (page three of this thread) I kind of lost you there to be honest..

Again, i don't think producers of BL motors use segmented magnets without a reason.... partial load is the reason.. (a-b repeat)

Problem is; heat is produced in the copper and in the magnets (electric magneticall lost?) the reason the magnets get heated is simple; everything with resistance produces heat, the speed of the electromagnetical field is higher than the speed of the magnet, (obvious) so it needs to absorb/compres something, with this absorbing/compressing is heat involved. reason for the copper to heat up is because of the resistance etc.

the magnet is used as a translator, to translate electro mechanical force into a rotating motion. I compare an audio transformer (as used in a tube amplifier) with this. It also works with electromagnetical forces, the packet of the transformer (E's and I's) normally are capable of producing a certain bandwith (limited in height (high frequencies), and due to statisfaction in depth (low frequencies) the thinner the E's and I's, the more efficient the transformer gets. And the faster it resonds to the electromagnetical 'signal' this translates in a higher achieved frequency (lets say 150khz instead of 30 khz)

The idea behind this is the reason i put this back towards the BL motors. That AND the fact that all the producers of bigger BL motors use segmented magnets, and some emails i spent with Daniel on this particular subject, made me conclude what i said before..

[GriffinRU]

Originally posted by Serum

Artur, I thought you meant in the earlier post that a bigger airgap (Increasing) gave less eddy currents? (page three of this thread) I kind of lost you there to be honest..

Again, i don't think producers of BL motors use segmented magnets without a reason.... partial load is the reason.. (a-b repeat)

If you review my post again, you will find out when and why air gap works.
(One-piece magnet to reduce losses – increase air gap, for segmented magnet losses are minimized that is why you can reduce air gap more. Cost more due to the high tolerances.)

Originally posted by Serum

Problem is; heat is produced in the copper and in the magnets (electric magneticall lost?) the reason the magnets get heated is simple; everything with resistance produces heat, the speed of the electromagnetical field is higher than the speed of the magnet, (obvious) so it needs to absorb/compres something, with this absorbing/compressing is heat involved. reason for the copper to heat up is because of the resistance etc.

Wrong for motor type we discuss. Both magnetic fields are synchronized.

Originally posted by Serum

the magnet is used as a translator, to translate electro mechanical force into a rotating motion. I compare an audio transformer (as used in a tube amplifier) with this. It also works with electromagnetical forces, the packet of the transformer (E's and I's) normally are capable of producing a certain bandwith (limited in height (high frequencies), and due to statisfaction in depth (low frequencies) the thinner the E's and I's, the more efficient the transformer gets. And the faster it resonds to the electromagnetical 'signal' this translates in a higher achieved frequency (lets say 150khz instead of 30 khz)

Every motor comes with inductive/capacitive/resistive ratings for phases. And based on them you can define what frequency response you get and what switching frequence to use and how efficiency will lay across
RPM range.

Artur

[captain harlock]

Ahem...well, I got pretty bored of this discussion and if there is no one who would like to change topic, then I will, but first I must give Daf an answer for his question regarding the Aveox motors:

Yes, Dafni, though I did not use any aveox motors I can give you some informtion about it:
These motors are sensor based ones and they are pretty similar in design to the novaks. They're made in England and since they're not segmented nor sensorless, we cant really compare it to the recent crazy powerplants. The only person I know about who used an Aveox motor was Mr. Cleff Lett the president of the R&D department at Team Associated. The Aveox he used was bolt into a RC10L3 pan car in order to break an old speed record of 59mph with that motor. He succeeded, indeed, after using a pack of nicad batteries that includes 24 cells and pushed the motor over 100000 rpm. He was able to break the speed record quite easily. He reached 111mph compared to the old 59mph. What I want to clarify here is that if HE used a Lehner 1920/5 motor with only 12-14 cells, he would have easily destroyed the 111mph speed record and saved himself all the hassle he went through.
As for a new topic....well, ....Mike, you said that it is possible for you to carry the Kontronik motors sometimes in the future. Is it possible that you will convince the people of kontronik to make a FUN700 motor with a 70mm long rotor so that we can use it in our monster trucks?:p

[GriffinRU]

Inside Aveox Motor



Artur

P.S. Novak HV4400 looks dramatically different...

[captain harlock]

Thanks for correcting me. I'm still not as informative as you guys, but I'm trying my best,anyway.:)

[captain harlock]

Whatever you say, pal.