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same motor LR vs SR

Discussion in 'Model 3' started by yodar77, May 8, 2018.

  1. yodar77

    yodar77 New Member

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  2. CheeseJam

    CheeseJam Member

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    Here's the quote: “Some electric car motors use the permanent magnet technology, probably the most famous is the Tesla Model 3 Long Range. All the other Tesla models — Model X and Model 3 standard — use induction motors,” said David Merriman, a senior analyst at metals consultancy Roskill.

    I think the author meant to say "Model X and Model S." Either way, it would make no sense for Tesla to use different motors for each battery size. I'm almost positive all Model 3 variants will use permanent magnet motors, unless they do something special for the performance version.
     
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  3. chilman408

    chilman408 Member

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    In Model S and X, Tesla would still limit the current draw (therefore less power) in software to the smaller batteries.
     
  4. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    The Model 3 motor is not a straight permanent magnet motor either, by they way. Other EVs like the Leaf, Bolt, etc. use true permanent magnet motors that make use of a large piece of rare-earth material as a magnet. The Model 3's motor is (rumored to be, not confirmed) a permanent-magnet switched reluctance (PMSR) motor. This motor uses a rotor that is mostly iron/steel, with small permanent magnets embedded to smooth out the torque ripple. In terms of the article, this means the Tesla motor uses a lot less of the rare-earth metals than other motors.

    However, I don't think there will be any difference in motor between the Model 3 LR and SR models. The only possibility here is that the (eventual) performance Model 3 might have something different.
     
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  5. JeffK

    JeffK Well-Known Member

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    The person quoted in the article is not a Tesla employee and has no knowledge on unreleased Tesla products.

    It's almost a guarantee the standard range version of the Model 3 will use the exact same motor as the LR. There's zero reason to have a different motor.
     
  6. Fusion

    Fusion Member

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    What's the differences between the Model S motor vs. Model 3. Advantages vs disadvantages?
     
  7. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    Model S and X use an induction motor, Model 3 uses the Permanent Magnet Switched Reluctance (PMSR) motor.

    Induction Motor Advantages:
    • Simple construction
    • Lower cost, because no rare-earth materials are used
    • Very high stall torque (torque @ 0 RPM)
    • Excellent torque control
    Induction Motor Disadvantages:
    • Control logic and system is complicated, requires precise engineering of the control algorithms to get smooth operation
    • Less efficient than other motor types
    • Rotor can easily overheat when providing high power for sustained periods
    • Because of induced rotor currents and voltages, electro-pitting of bearings can occur (was a big problem in earlier revisions of Tesla's large drive motors, required ceramic bearings to fix)

    PMSR Advantages:
    • Simpler construction compared to other standard permanent magnet motors, but not as simple as induction
    • Uses much less rare-earth metals than standard permanent magnet motors, but still uses some to smooth out torque ripple
    • Rotor is mostly iron/steel = less expensive
    • High efficiency, on-par with standard permanent magnet motors
    • Rotor runs much cooler than induction motor, even when operated at high power levels for sustained periods
    • Control logic and algorithms are simpler than induction motor
    • No rotor induced voltages or currents, can use standard steel bearings
    PMSR Disadvantages:
    • Lower stall torque (torque @ 0 RPM)
    • Can have torque ripple, especially at low speeds
    • Buikier than induction motor or permanent magnet motor of similar power
    • Cannot provide regenerative braking at very slow speeds, unlike permanent magnet motor

    Tesla Semi is rumored to be using PMSR motors due to the ability to keep the rotor cool under sustained high power.
     
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  8. ImEric

    ImEric Member

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    I imagine that the performance model might include a large, rear induction motor. I have nothing to base this on, it's just a guess. But if you want to do Ludicrous mode, it seems like a higher power option might be the way to go, even if they even it out with a permanent magnet in front. IDK if combining the two would even work, or be feasible but that's my guess... based on nothing.
     

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