Published on January 31st, 2016 | by James Ayre


Tesla’s Top Motor Designer Talks Motors

January 31st, 2016 by  

Originally published on EV Obsession.

Tesla’s lead motor engineer (Principal Motor Designer, to use the official title), Konstantinos Laskaris, recently gave an interesting interview to Charged EVs, where he expounded in detail on the company’s direction and decision-making process to date.

Konstantinos-LaskarisThere was a bit following on a question involving the use of algorithms in motor modeling that stood out to my eyes, in particular: “Beyond that, through good motor modeling, we can achieve the best optimization — which means we can achieve exotic performance without the use of exotic materials and exotic manufacturing.”

The bluntness concerning the trade-offs of different performance enhancements was also quite interesting:

So the question is, can I have everything – both high efficiency and high performance? The answer, unfortunately, is no. But you can make intelligent choices between things that are competing with each other.

This is the beauty of optimization. You can pick among all the options to get the best motor for the constraints. If we model everything properly, you can find the motor with the high performance 0-60 MPH constraint and the best possible highway efficiency.

Another example is the overall motor efficiency versus its cost. There are cases where making a motor in more expensive ways could potentially increase efficiency and buy off multiple times the cost difference by saving money on the battery, or other aspects of the car. So, if you are able to model the motor efficiency and costs accurately, you can plot it against battery cost savings. Now you can see that the optimal motor for total cost minimization is often different from the cheapest motor.

Arguably this is all “common sense,” but it’s nice to hear it stated bluntly — and it’s nice that Tesla seems to have such competent people working for it. Makes me even more impatient for the Model 3 reveal that’s fast approaching….

There’s a lot more to the interview, and it’s quite interesting, so I recommend heading over to Charged EVs to read it. (The comment section for the article is quite interesting as well, with a good discussion of the comparative merits of induction motors, like the ones Tesla uses, and permanent magnet motors.)

Check out our new 93-page EV report, based on over 2,000 surveys collected from EV drivers in 49 of 50 US states, 26 European countries, and 9 Canadian provinces.

Tags: , ,

About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • Bob_Wallace

    Fine. Talk about the process and leave your company name out of the discussion.

    I’m not singling you out. We had three companies spamming their companies yesterday. Some of the companies might be doing great stuff, but I don’t have the time and ability so sort the sheep from the goats.

    If you’ve got a great product/service (in your opinion) then contact Zach and see if he wants to do an article on it.

  • eveee

    Everything you wanted to know about electric traction motors but were afraid to ask.

  • Sreehari Variar

    You could’ve just said “ChargedEVs got to talk to the Chief Motor Designer of Tesla” the link is below”.

    I don’t see anything more than that in this article.

    • This was “the highlights.” If we went the route you suggested, it’d just be a link in an EV news roundup. This brings it much more attention.

  • Mike333

    Love that now you can pick a Tesla based on Performance or Range.
    Hope to see that in the Model 3.
    Efficiency is now King.

    • Steve Grinwis

      Screw efficiency. EV’s are so retardedly efficient, that the difference between the least efficient EV motor out there, and the best possible efficiency motor is about 20% in range.

      Give me ludicrous mode. Give me AWD. Give me tire smoking launches. Give me so much acceleration, that I don’t dare try it with my grandmother in the car, because there’s good odds it’s not survivable. Tesla has this right.

      EVs aren’t going to win the hearts and minds of people because they’re efficient. They’ll win because they’re so much better to drive. That’ they’re cheaper, and less polluting will be the icing on the cake.

  • Mike333

    This is the problem with FORD. This conversion isn’t happening.

  • Ivor O’Connor

    The guy got his doctorate in modeling motors. He spent most of the interview extolling the virtues of modeling motor designs, often contradicting himself like here:

    If we model everything properly, you can find the motor with the high performance 0-60 MPH constraint and the best possible highway efficiency.

    So the question is, can I have everything – both high efficiency and high performance? The answer, unfortunately, is no.

    Sure you can put qualifiers and read it like people read the bibles of their favorite religion. To me though it was lots of tooting his own modeling horn and lots of BS applied liberally everywhere else.

    • Zorba

      I think it’s important to consider the constraint he mentions when modelling though. So if you didn’t require that 0-60 performance you would end up with a different motor, one that’s more efficient. But if you then impose a constraint on the model (“I must have this high performance over 0-60”) you then try and get the most efficient motor you can which still delivers that performance and so complies with the constraint. So it is a trade-off, and the end result is different to a motor designed purely for efficiency.

      • Ivor O’Connor

        The 0-60 performance and efficiency requirement was the context in both questions in which he contradicted himself. He did not get into any of the details which would have given us outsiders something to sink our teeth in. Instead he just pontificated on the virtues of modeling and couldn’t even do a good job of that.

  • neroden

    Permanent magnet motors are great when the motor power requirement is low enough that they can use simple iron magnets. When they require rare earth magnets, they start being a bit wasteful.

    • Ivor O’Connor

      They’ve come up with ways to have rare earth like magnets with no rare earth. The comment section was full of drivel linked to a bad NPR segment.

  • JamesWimberley

    Laskaris does not mention top speed, only 0-60 mph acceleration. This is rational, as 99% of users will never drive above 160 km/hr (100 mph) and that very rarely indeed, as most roads in the world have speed limits much lower than that. (The conservative Spanish government announced a hike in the motorway speed limit from 120 kph to 130 kph, but has postponed its introduction for lack of real interest.) But it’s still absurdly prominent in automobile journalism, and in Germany.

    • Steven F

      Top speed is determine by air and tire friction, vehicle weight, and the slope of the road. None of these factors are part of motor design. So he didn’t talk about it because he doesn’t deal with those items.

      • JamesWimberley

        He would have if Musk attached any importance to it.

      • Adrian

        It’s also a function of maximum continuous motor output (which he most certainly does deal with). In the case of a Model S, that is far, far less than peak output, quite likely < 100kW.

        • Otis11

          Yes. But IIRC, the model S top speed is actually limited by peak sustained power output by the battery… not the motors.

          • Ivor O’Connor

            The motors are dramatically less efficient at top speeds. And this causes heating problems. The heating problems are dealt with by software that limits the power supplied to the motors. Making the Tesla a slow moving slug on race tracks like the Nuremberg. It would have been great if this guy would have addressed some of these issues.

          • eveee

            Hmmm, I think its the reverse, but Tesla isn’t saying. IMO, high speed is good for induction motor efficiency.

          • Ivor O’Connor

            You can get enough info to make deductions by watching youtube videos of Teslas racing on the Nuremberg raceway. They very quickly overheat and from then on is governed to about half power.

          • eveee

            Yes. I was referring to efficiency there. Efficiency is good at high rpm, better than low rpm. And yes, the Teslas are not designed to maintain high speed indefinitely. Its not a race car. Its a fast luxury sedan that can drive all day at max highway speeds, not race speeds. Come to think of it, it implies that Tesla optimized their system for highway speeds. The whole effort, IMO, was to implode the whole range anxiety myth. 🙂

          • Ivor O’Connor

            Nope. You can deduce efficiency is not very good after 60 mph by the fact Tesla’s lose to all ICE vehicles of equal or sometimes much less HP. Do a rolling speed race starting at 60 mph against an ICE vehicle and watch the results. Only reason the Tesla can’t accelerate like it had is because of inefficiency at those higher RPMs.

          • eveee

            Efficiency does not equal horsepower output. The motor response has to be separated from the load to get a picture of the results. Induction motor horsepower falls at very high rpm. Remember here, that 60mph in a Tesla is mid to high rpm. Max rpm is much higher at about 120mph. Any vehicle will slow acceleration at high velocity, particularly above 60mph, because air resistance will increase non linearly. At low speeds its just accelerating mass. At high speeds wind resistance dominates everything.
            Notice that low efficiency of an electric motor is numbers like 86%. That hardly very inefficient compared to other processes. The efficiency varies only slightly, not dramatically like an ICE.



            You have to add the inverter efficiency to that the result.
            Here is a graph of the Tesla motor response. Now you can see how complicated it is.

            Here is a motor for an electric motorcycle.

            The power and torque curves for Tesla.

          • Ivor O’Connor

            You must not have read what I wrote, so let me stop you right here

            Any vehicle will slow acceleration at high velocity, particularly above 60mph, because air resistance will increase non linearly.

            Remember I said the Tesla will lose to any ICE vehicle of similar HP at a rolling start of 60 mph to 125 mph, and even lose to ICE vehicles of much less HP too. That’s all because the motor is too inefficient at those RPMs.

          • eveee

            You are probably right. But I can’t figure out what IIRC means. 🙂 Im just so old school. Actually, It looks like the battery and motors are designed to poop out at about the same point. Hard to tell which. Telling that a bigger battery allows higher top speed. But they did go to two motors, didn’t they? I really want to say an analysis of this gets pretty complicated. With two motors, one is really dominant at high speed. The gearing is different for the two motors. The other, who knows how much it contributes at top speed if any. I have not heard any papers by Tesla on it. Its not very public info.
            Maybe a discussion limited to the single motor variant would be easier. There, you run into max motor rpm limits. In the sense that max hp is closer to max rpm, its true the motor limits top speed. Its awfully hard to optimize a single gear motor for max speed and acceleration. I have gone through this before. Its what rpm you put your torque. If you gear higher for higher top speed, the acceleration suffers. If you gear for max acceleration, the top speed suffers. Its a familiar dilemma to ICE gear heads, but the game is a bit different for EVs.

          • Otis11

            IIRC – If I Remember Correctly

            And yes – things may have changed with the dual motor. I remember a racing guy doing an analysis on it back when he got his Model S, but I believe that was before they went to the dual motors (I think he had a P85.. that was a long time ago though).

        • eveee

          Too many far(s). LOL. Most EV motors don’t have a far, far difference between peak and continuous horsepower.
          For example, the Delco Remy induction motor. The difference is show in the dotted vs solid lines. At low rpm, the difference is about 50%. Thats understandable, because there isn’t enough motion to dissipate heat, and more energy is lost in IR drop, because em induction is less efficient with less relative motion (dphi/dt). Said differently, the rate of change of flux is slower.
          At high rpm, the difference all but disappears. That shows the tradeoff between low rpm efficiency and power vs high rpm.
          This is all predicated by the desire to have a single speed drive system, which is wise, because a complete gearbox is extra space, weight, and efficiency penalty.

  • Freddy D

    Great insight.

    “arguably this is all ‘common sense'”…. One might intuitively think that taking an optimization approach to R&D is common sense. It is certainly quite logical and this approach does result in economic and competitive outcomes. Yet, in practice, it’s somewhat un-“common”. Looking back in history at another automotive organization, GM sold cars through the 1970s and 1980s with 307 cu-in (5.0 liter) engines that made 140 horsepower. (look it up – I’m not joking, honest). Did they use optimization of valve configuration, exhaust config, timing, fuel delivery and all the attributes of the system to achieve these numbers? Of course not; that’s what Honda did with the VTEC technology that managed to get that much power out of an engine half the size, half the weight, cheaper to make, fit in a wider range of products. GM was a huge company back then and lost over half their market share.

    Optimization is a powerful technique in R&D and requires a strategic vision to implement it right up to the top of the organization. It also requires R&D and product-minded leadership at the top of the organization to broker the inevitable trade-off decisions that must be made between parts of the product and parts of the organization. Ponder the backgrounds of executive leadership at many organizations today.

    • Omega Centauri

      I think there are often practical constraints. If you are buying commodity parts, or even parts that are used by other companies/divisions, you can’t just change the size/geometry of them, you can only select from a limited number of parts.

      Of course there are many things you’d like to take into account, including durability, and repair/replacement costs. And many of these things may be poorly known at the time of design.

    • Mike333

      GM, in 67 put out a 250 cubic inch 6 cylinder, with a 1, you read that right, a 1 ( ONE ) barrel carburetor, and a 2 ( TWO ) speed automatic that made Optimistically 105 horsepower.

      And a V8 option in the same car.
      Market differentiation.
      Price levels.
      You could say GM was a Sales and Marketing company first.

      But, today the Volt is a leadership product.
      The Bolt? Almost, too much like it’s Spark/Buick cousin.

  • 3DFS Software-Defined Power

    This statement by Konstantinos Laskaris is incorrect now. Software-Defined Power allows for BOTH high efficiency AND high performance.

    “So the question is, can I have everything – both high efficiency and
    high performance? The answer, unfortunately, is no. But you can make
    intelligent choices between things that are competing with each other.”

    • JamesWimberley

      You can push out the production function, but it’s still convex. TANSTAAFL.

      • 3DFS Software-Defined Power

        Are you referring to the degradation curve? There is no degradation curve in batteries with our technology. It is not a free lunch, it is just the appropriate way to maintain electricity.

    • Mike333

      A larger motor yields larger performance numbers, but burns more electrons and wind energy. For some of us having an engine that can put out Ludicrous power is, well non-sensible.

      • 3DFS Software-Defined Power

        It is not about ludicrous power, it is about a balanced approach.

        From a LI ion battery perspective, we eliminate and prevent the growth
        of dendrites and maintain near ideal battery life through our real time
        battery chemistry monitoring and feedback system. We accomplish through
        hypersensitive digital sampling of the electricity charging and
        discharging the battery and disaggregating that electrical signature in
        real time. Batteries using our technology do not degrade over time and
        provide maximum and consistent power density.

        From a motor perspective, we
        provide advanced and incredibly effective motor control. We can provide a
        built in BMS system which will allow the highest efficiency, with near
        ideal torque, ideal force, and an optimized magnetic flux at all times
        regardless of motor performance.

        • Bob_Wallace

          Don’t spam us, bro….

          • 3DFS Software-Defined Power

            Don’t troll me, bro… If you do not understand, ask.

          • Bob_Wallace

            Pay attention.

          • 3DFS Software-Defined Power

            I am not really sure what you are attempting to say. I suspect it is some combination of lack of understanding, an inability to investigate, and a penchant for superiority trolling.

            If you are interested in learning more about Software-Defined Power and how it changes motor control and batteries, I will be happy to discuss, but if you are just hacking away at the comment section like a high schooler, I have better things to do.

          • Bob_Wallace

            I am saying that if you want to participate in conversations here you are welcome. But don’t try to use comment as a way to push your business.

            Is that clear enough?

        • WeaponZero

          You are effectively saying the same thing Konstantinos Laskaris is saying. That you need balance.

          There will always be a balance between performance and efficiency. Better efficiency can increase performance too. But you will always have to compromise somewhere.

          Currently, Tesla has the most efficient motor of any production EV while offering the best performance.

Back to Top ↑