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P85D Front Drive Unit

Discussion in 'Technical' started by perreoapocaluz, Jun 12, 2015.

  1. perreoapocaluz

    perreoapocaluz New Member

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    Hey!

    I noticed in the picture of the underside of the Tesla Model S that the front drive unit is much smaller than the rear, which makes sense given the FDU is of lower power than the rear but it seems so much better packed?

    I have seen plenty of rear drive units and inverters (in the triangle configuration) but none of the front. I wondered how differently its packed from the RDU.

    Any teardowns of these components I've missed?

    PAPL
     
  2. TEG

    TEG TMC Moderator

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    It is more vertically oriented with the motor and inverter on top, so you don't see so much from below.

    front-motor.png
     
  3. jerjozwik

    jerjozwik Member

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    is... the inverter in that image? because i dont see anything inverterish.
     
  4. JER

    JER Member

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    #4 JER, Jun 12, 2015
    Last edited: Jun 12, 2015
    I've yet to see internal schematics or images to confirm this, but from what I understand the new drive units have the inverter/PEM integrated with the motor. It could also be the same opposite-the-motor layout as the old drive unit, but smaller.

    Edit:

    I think this is what's going on.

    inverters.jpg
     
  5. TEG

    TEG TMC Moderator

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    Yes, I think that is right. Your are showing the 85D (not P85D) with the smaller motor in back. You can see the gap where the frame could allow the bigger inverter of the performance motor to fit if this had been a P85D.


    (P85D):

    p-motor.png
     
  6. TEG

    TEG TMC Moderator

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  7. JER

    JER Member

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    There's lots of video of the old motor and inverter/PEM internals around, but lamentably nothing that I’ve found for the new ones.

    It is intriguing that the old inverter appears so much larger than what we presume is the new one. Certainly more than the ratio of power output.

    It’s well known that an improved IGBT part from International Rectifier was the reason Tesla could drop the (very troublesome) two-speed transmission requirement so late in the Roadster’s development. I wonder if there has been a similar technology improvement, or if Tesla has just figured out a better optimised way of using the same parts.
     
  8. TEG

    TEG TMC Moderator

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    I think the power and torque characteristics of the new motor are rather different from the old. It may be operationally different than the original Model S motor.

    As I recall, there was some torque chart published that suggested it had lower overall torque, but it didn't have the same dropoff slope as the original motor so it was better at keeping HP into higher RPMs.
    (Maybe part of the reason they started talking about higher top speeds?)
    Random guess - maybe newer IGBTs have faster switching speeds (but not necessarily more power delivery capability?)
    I have no idea what is going on, but it feels like they are taking a different approach on the new motor.
     
  9. perreoapocaluz

    perreoapocaluz New Member

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    Yeah... its amazing how well the front inverter seems packed (Tesla claims 2/3 of the performance but its package is def less than 2/3 of the original inverter) Maybe its not in a triangle configuration (with empty space in the middle?)

    Seems no one has really peeked at what it actually looks like on the inside, I'm hoping a brave soul posts some pics soon.

    Roberto
     
  10. SabrToothSqrl

    SabrToothSqrl Active Member

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    If anyone wants to give me any free Tesla motor I promise to throw it in a jet ski and see what happens :)
     
  11. jerjozwik

    jerjozwik Member

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    been watching "one crazy summer" recently?
    capture012336qw7.8466.jpg
     
  12. SabrToothSqrl

    SabrToothSqrl Active Member

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    I have not. I'm just dying to back a 200HP electric ski into an 'electric only' lake and really mess with people :)
     

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