After reading some posts here and there about which motor is good and why...

I have a question to those who used them and did felt or measured the difference.

What is efficiency difference (in %) between lehner, BK, Hacker, Feigao, Nemesis, Kontronik and Aveox motors.

Artur

P.S. similar size and maybe ratings...

Lehner and BK are the same, as are the nemesis and the feigao's.

I can tell you that normally a lower KV setup on a higher voltage gets less hot. The Lehner motors (19/22 series) are very good. They don't get too hot if geared with sence.

I can't tell you anything from the kontronik or the aveox motors, but like i said before, the segmented kontronik motors would not surprise me, if they are the same quality as the lehners (also being segmented)

Promod is the one who does measure his setup, he uses an eagletree system for this.

I also read that you stated that the Xl size motors (feigao/wanderer/nemesis) are rated for 1200 watts. i've seen a calculation of another member, that said it was capable of pushing out 2200 watts at 92 percent efficiency. not bad at all imo.

I prefer a higher voltage setup, with a bigger low KV motor (such as an 2240 on 6-8S lipo.)

I believe all feigaos, wanderers and hackers are similar in terms of effeciency, but the Aveox ( specially the sensored based ones) are weaker than the others. Probably the most powerful are the 19-22 series of lehners followed by Kontronik's full line of motors( all kontronik motors use segmented magnets) and the Tango is the only motor capable of challenging the 22 series ( the 2230 at least).

Oh, from what I understood from kontronik is that their motors' effeciency is near 89% at load.

Higher voltage applications will always be more efficient then lower.

And let’s not be so biased with segmented magnets, we talking about 1% max difference. Do not forget about wiring (wire gauge, wire type, delta/star …)

So from what I am reading here looks like we have problem with correct gearing not motors. :)
Do not get me wrong; what I am trying to say is when we select gearing we look upon Kv ratings of particular motor. But there is another factor to consider, efficiency which is not linear at all. And sometimes we need sacrifice something in order to achieve another. Based on your feedbacks lehner motors have better efficiency across wider RPM/Load range then others.

But I am not convinced 100%. Because main argument for lehner and kontronik motors to be the best based on type of magnet used. Is it possible we are missing something?

Artur

P.S. My personal opinion Aveox motors are not that bad.

The Lehner motors have a very efficient winding technique as well, which is surely a major factor in their efficiency. The segmented magnets also are a factor (particularly at partial throttle, where our motors are most of the time - this is where the efficiency difference is noticed/realized with the segmented magnets). Of course gearing plays a major role in heat generation as well. There are tons of posts on the forum about heat that are ultimately addressed with gearing changes(some over geared, some undergeared).
The Lehner motors(19 series, 22 series, 15 series etc.) simply run much cooler in most environments. The Lehner basic series(which shares the windings with the 19 series, etc.) is also quite efficient and powerful, but there is a noticeable heat difference vs. the 1930 motor(which is about the same size). This indeed suggests and highlights the benefit of the segmented magnets, as the motors are otherwise very similar in construction.

It is not fair to compare efficiency of 5000Kv motor with 1000Kv.

Basic 4200 600 Watts @ 45 Amps 4200 145g
Basic 5300 700 Watts @ 55 Amps 5300 145g
Basic XL 2400 1300 Watts 60 Amps 2400 215g
Basic XL 2800 1300 Watts 72 Amps 2800 215g
Basic XL 3100 1300 Watts 80 Amps 3100 215g
Basic XL 3600 1300 Watts 97 Amps 3600 215g
Basic XL 4200 1300 Watts 110 Amps 4200 215g
Basic XL 5000 1300 Watts @ 125 Amps 5000 215g
1930/6 1200 Watts @ 30 Amps 3483 230g
1930/7 1200 Watts @ 30 Amps 2986 230g
1930/8 1200 Watts @ 30 Amps 2613 230g
1930/9 1200 Watts @ 30 Amps 2322 230g

I cannot see how you can compare them.

Artur

P.S. Data from finedesign

Who said anything about comparing a 5000Kv motor to a 1000Kv motor? My comparison was based on similar sized and Kv motors(1930/8 vs. xl2800 or a 1930/9 to an xl2400 for example). The basic xl series are labeled as 1300 watt motors, while the 1930s are labeled as 1200 watt motors. They are similar in size, similar in winding construction, but the 19 series have a segmented magnet(and run noticeably cooler as well).

Mike you forgot about current...
To get 1200W from xl2800 you need 72A
1300 from 1930/8 only 30A
And difference in losses associated with current would be by far greater then magnets.
Artur

P.S. Higher voltage applications more efficient always.

I really lost your point..

Well, like i stated before and before, in opposite to your theory, segemented magnets are BETTER in partitial load than non segmented. this is a reason for gettin less hot (higher efficiency) key is EDDY CURRENT

I lost your point in this discussion about this. I really don't quite understand the reason for this discussion?

It is not the TYPE of magnet. It is about the way the magnet is used in the rotor, which is segmented, that makes the higher end motors superior to the non segmented.

Their really is no way around it, listen, the magnet is heated up somehow. Daniel and my point of view is that it is because of the eddy currents.

1 percent of a 1500 watt setup is 15 watts of lost, so it really DOES matter. 15 watts is enough to solder with..

So based on your 'theory' it doesn't matter if you have or don't have got a segmented magnet.

Go tell the main producers of high end motors. They all use segmented magnets.

they all do use segmented magnets.

Here are some simple facts to get a high as possible efficiency;

smallest airgap possible, strongest magnet available, square or hex winding wire to use as much copper as possible, in order to replace air/isolator with copper. the highest setup voltage as possible.

Your theory/quote is wrong on the 1930/8 too buddy....

here is the thing, it has got a KV of 2615.

max rpm is 60000 (not the most efficient RPM range to begin with, but i niglect this)

60000/2615=22.94 volts.

1300 watts at 22.94 volts= 56.67A.

getting out the popcorn....:rolleyes:

Those numbers are meaningless, Artur(72A and 30 amp). The watt output is simply a function of voltage x amperage x efficiency. You don't necessarily need 72 amps to get the power from a 2800xl motor, nor will the 1930/8 produce 1200 watts at 30 amps unless it has serious voltage(40 volts to be exact - not counting efficiency losses!). I am talking real life here, not the information you can read and interpret many different ways.
Many people read those amp numbers and get the wrong idea. They are mostly meaningless for this discussion.
My comparison is based on a similar Kv motor, with a similar size and a similar winding construction in a similar application with the segmented magnets being the primary difference. The results are simply that in the r/c car application where partial and varying throttle is used, the segmented magnets simply perform noticeably better. The non segmented rotor may show similar efficiency on paper, but in partial load applications, it is simply not as efficient as a segmented rotor. The non segmented magnet will produce high efficiency when used at their optimum amp draw and voltage (when used in an airplane at a constant throttle, for example, there is little benefit to a segmented magnet), but as you already mentioned, the efficiency is not linear and is/can be significantly lower than their stated values in a car/truck application.

that power of the 1930/8 would need 1300/30=43.33 volts. at this voltage the 1930/8 would turn around with a 113000 rpm..

Needless to say, that it will die and burn..

Exactly my point...the posted "amp values" on Chris's site are meaningless for this discussion. I used 1200 watts to get 40 volts (using the info from this post, the 1930 has a 1200watt rating vs. the 1300 watt rating of the basicxl), vs. your 43.34 volts and 1300 watts(I actually had this typed out, but changed it based on the 1200 watt posted power output already discussed in regards to this motor). The point is that the "current losses" is not relavent in this discussion.

I would like to see someone soldering car battery posts with 15W :)

Anyone how much power requires to heat up 250g chunk of copper from 70F to 100F?

Motor specs are "meaningless" only in case if you do not know what it means.

My point here is that better or more efficient magnet (magnet is the same, but one piece v.s. segments – what I called magnets types. Maybe wrong definition.) of course better choice but lets be realistic and not be confused with something which we don’t know for sure.

As I stated before segmented or not, maximum contribution is 1%. With bigger motors it is makes perfect sense to make it segmented but with smaller ones – you know the answer.

Artur

P.S. If I am correct Finedesign CURRENT specs are for maximum efficiency but that might not correspond to maximum or rated power.

Maybe we should calm down and analyze what we have?

Actually I have a better idea, lets build dyno and check...

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?

Wow, what have I started here? Interesting, boys. But everything that matters for me are real life experiences from people who know lots of different setups. I learned myself that those "amp-calculations" are totaly useless for us.

It's also interesting to see how some discussions reveal personalities ;) Entertaining, for sure.

peace, lads
DAF

i thought you allready knew about my darkside Daniel? ;)

Papa, would you please be so kind to share some of your popcorn?

Popcorn comin' your way.....;)

:L: yeah, I know you Rene. Was not particulary directed at you or anybody else, just a general remark ;)

Does anybody here run one of those Aveox motors?

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..
http://home.hetnet.nl/~henkvancann/spda/popcorn.JPG

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

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

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!). :)

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)

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. :)

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

.http://www.unlimitedengineering.com/...9/DSCN1884.JPG

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..

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.)

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

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

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

Inside Aveox Motor

http://forum.rcdesign.ru/index.php?a...=post&id=12816

Artur

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

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

Whatever you say, pal.

And I will encourage you to do that.
I learn new things every time I read somebody’s post, doesn’t matter how good or bad it is, right or wrong for that matter.

Artur

Thanks, Artur. I'll surely do my best.

Artur,

I know my thing about an airgap, i just told you that i understood DIFFERENT from another post of yours in this thread.

To tell you the truth, i've got the feeling that you are not completely aware what your talking about. In another post, you recommended a user to get 2 18.61's to one set of 12 cells. (good when you want to kill your cells for sure!)


Appearantly you did hear something;

ANY magnet and has got this character. otherwise you would have 0 lost. It is about the difference in speed of the electric magnetical field AND the slower moving magnet! who are you to argue about this?

About your last quote;
I was talking about audio transformers to explain something to you


And here it gets interesting to me;

Show me the formula please!

Just dont start a fight here, or else somthing really bad is gonna happen!

I have nothing to say here...

Maybe that will help with L/C/R... (from google)

Artur