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Efficiency of Lehner motors
Does anyone know what the Efficiency of the Lehner motors are?
Does it vary from size or kv of the motor? I think every model of motor is different they will have a different sweet spot where it has its max efficiency at a certain rpm...etc.. |
The sweet spot for lehners are around 35K.. I think they are 85% efficient under partial load, maybe Rene or somebody else could scope in on this.
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I think their over 90% efficient but I could be wrong
I think that’s one of the reasons why lmt motors are so expensive |
They are very efficient. They are expensive for several other reasons ;
Hand wound Segmented magnets Made id Germany :) GERMAN ENGINEERING IN DA HOUZZZE! ;) |
Efficiency will vary a bit. Factors include voltage, wind, load, etc. I imagine the efficiency range for our use will range from 60%-90% with the Lehner motors.
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I was referring to the efficiency % that they state in the specifications so I can compare motors.
Isn’t it the efficiency that counts mostly? If these lehner motors are so good (and they are!!!) why don’t they supply specification with them? When I got mine and I just got the motor in a tube and that’s it:030: |
Nope, efficiency is one thing, but it needs to be at a certain load.
Here, check this site; http://lehner-motoren.com/motordia.php?la=en |
I guess it is not clear how to use my program...
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This is measured data, not calculated.
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I randomly clicked one of the 1940 specs and efficiency was 91%...damn.
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I want a 110% efficient motor...
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Good point, we don't need a superconductive controller to get to a 100 percent total efficiency that way..
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To create graphs you need motor Kv, I no load, I max, Resistance. To create more sophisticated graphs you need to add inductance, inertia and core parameters. But for RC applications the first 4 constants will do the job of defining efficiency, power, torque and current draw. As reference you can check any motor manufacture datasheets for motors or even Lehner excel spreadsheet where you can click on cell and check for math behind. I was trying to bring all motor data under one roof :) |
But here is the question; you say lehner date is calculated? because this is not the case, it's real measured data.
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I don't know artur.
They claim it's measured. I thought dafni told it was done with a prop. why is the current changing, as well as the voltage? It would be easier of it was used as a set parameter. And can you explain the large dip in efficiency with this one; http://www.lehner-motoren.com/diagra....s26_liste.txt |
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When you add timing to equation it becomes tricky, in general with timing set at zero (my program default, adjustable in future) efficiency of the motor has linear relation factor (in calculation) with motor RPM, when you change timing you pushing this relation to be less linear across entire RPM but to be higher in the mostly used range. That is why you see a big dip in efficiency when you get out of tuned efficiency envelope. |
Nice theory, but since they also included the Delta and the Wye windings, it would make the calculations far more complicated than you are describing. PLUS they DO use timing in their numbers. This STILL doesn't explain why they don't use a set number of voltage. (this is variable as well) I know one reason why this number would be variable, but it simple makes no sense to 'assume' a resistance of a battery, since this is variable as well..
And now we are getting deeper into it; why are brushless motorcans not made from plastic? aluminum is magnetic active when there is a magnetic rotor is turning in it. (even a U, or an unclosed piece of aluminum has this 'problem') I think plastic motorcans would help making a brushless motor even more efficient. but here is the big q; What makes you think/presume they use calculated data instead of measured? agai'n; Daf mentioned they use a propellor to measure the power; the other numbers that you call measured is static data. |
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Can material will make big difference if it would be close to magnetic field, for current configurations we talking about fractions of %, which still loss but so small. I am not following you about constant V, You can dyno motor at constant power, but then it would be not easy to read data. And actually there are cases when you would like to test motor under constant power, but you talking about voltage. As for Q, click on any cell in calculated area and then check in entry field, you will see formula on how particular cell data was obtained. |
Heck, now i see.
Okay, that's calculated for sure. I never paid close attention to the excel sheets.. |
Rene, I said they use props to get a loaded KV value, nothing else.
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Okay, thanks for clarifying Daf.
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