I didn’t want to imply that they were somehow exceeding the limits of the battery pack - just saying that there are other components (ie, the inverter) that may be responsible for limiting power to the motors. I thought I saw something that suggested the performance models would have higher capacity components, but that may have just been blind speculation - hard to keep track of exactly what is comfirmed.
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New AWD Motor Info from fueleconomy.gov
- Thread starter spesler
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Are you sure about that? Maybe the front motor is shared between the D and P, while the rear motor is shared between the RWD and the P. (With the binned ones going to the P.)
I think there are three different motors...
boriszima
Member
3 motors? Seems like a lot of work. Likely same motor in rear for all 3 models just limited to power due to testing
I thought Elon's phrasing implied/suggested/stated (I forget) that the P motors would be selected as the "stronger performing" rear motor. But looking at the image in the OP it seems more like the flow is more like...
1. build rear motors
2. build front motors
3. split rear motors into 3 buckets: { high, medium, low }
4. repeat if PAWD order exists: if front and 'high' rear available, build PAWD car
5. repeat if AWD order exists: if front and 'low' rear available, build AWD car
6. build 1 RWD car using 'high' or 'medium' rear
7. return to 1
Put another way, it seems like P AWD gets the 'high' rear motor, AWD gets the 'low', and RWD never gets the 'low'.
The reason to put the 'low' in the AWD is because it's getting 89% utilization whereas the RWD gets 100% utilization.
Or did I go off the rails somewhere?
If I didn't this might somewhat explain why the non-P AWD is such a value.
1. build rear motors
2. build front motors
3. split rear motors into 3 buckets: { high, medium, low }
4. repeat if PAWD order exists: if front and 'high' rear available, build PAWD car
5. repeat if AWD order exists: if front and 'low' rear available, build AWD car
6. build 1 RWD car using 'high' or 'medium' rear
7. return to 1
Put another way, it seems like P AWD gets the 'high' rear motor, AWD gets the 'low', and RWD never gets the 'low'.
The reason to put the 'low' in the AWD is because it's getting 89% utilization whereas the RWD gets 100% utilization.
Or did I go off the rails somewhere?
If I didn't this might somewhat explain why the non-P AWD is such a value.
Might also be that AWD maxes out the HV infrastructure from the battery pack, and the P model gets fancier parts there (remember the fancy 'smart' fuse for the S/X P models to enable higher amperage operation). Perhaps the AWD is just the peak they can safely and reliably get out of the AWD/RWD battery - so they software limited rear power to not exceed it. If so, it is likely that it can shift power to the rear motor if the front motor isn't able to use all of it's allotment, and the listed power ratings are peak combined under normal traction conditions (vs limiting front motor another 23 kW and applying it to rear motor).
Knightshade
Well-Known Member
As we've been over in other threads, the inverter is part of the drive unit.
The P and AWD use the same, lot sorted, drive units.
Lot sorting would make no sense if they were not the same physical parts.
Why?
They can do the exact same thing in software for free, rather than your idea which costs a significant amount of time and money and internal churn to add parts to development and supply chain...and end up with exactly the same results as doing it in software and using a single rear motor across all 3 versions.
Battery can handle 370kw, which is more than even the P-AWD is drawing for both motors based on the EPA output #s of the motors. And the 3 doesn't even have physical fuses.
Be nice if somebody had access to Teslas parts ordering system at a service center or something so we can finally put to bed for sure the idea they're using a slew of complex different parts rather than just doing it all in software...but until then any news story I can find on it seems to also state they're the same actual motors-
Tesla unveils faster and more powerful Model 3 dual motor AWD and Performance versions
Eletrek said:
ℬête Noire
Active Member
OR it was mostly marketing fluff to try help give potential Performance customers a sense that they were buying something literally very physically different rather than really mostly conceptually different. So it doesn't have to be all that complicated, nor the differences between them all that much for performance. Just a tiny bit less chance of failure.
The higher current you draw out of the battery the more stress it is going to put on the battery. This is exponential so that last bit extra by the Performance taking the battery to it's currently assumed limit is a lot more wear/risk of damage. The battery is easily the most expensive part of the car, estimated at 40%(!) of manufacturing costs for the LR. So it's way more expensive to replace if that fails than one of the drive units fails.
The $11K Performance is partly a higher insurance premium for that larger risk, partly phat margin because if you want the premium acceleration you're going to pay the premium price. Welcome to Nice Things. That's only maybe 30% above a past the higher Model S "uncork" fee Tesla has charged? I'm not well versed is that labyrinth of history.
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diamond.g
Active Member
Lots of power for the regular AWD version, for the weight, is that much power required to hit 60 in 4.5 seconds? Seems like BMW 340xi can do it with lots less power (and 200# less weight as well).
ℬête Noire
Active Member
That's exactly what I'm assuming I'm buying. A I Can't Believe It's Not An 340i w/X-drive that never needs to stop at a gas station [and is likely slightly quicker]. Unless Tesla managed to somehow screw up the handling in the process of adding the front motor.
Hey, maybe that's what I'll put on in place of the fugly "Dual Motor" badge (that I'm going to ask Tesla not to install to start with). I'll install 340i and XDrive badges...or better yet an "M340i".** LOL
** No, not actually.
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These numbers don't show what the change in peak motor current is at the low end. The DU could be much higher current (amps) when under the max power limit (amps * back EMF voltage).
That was true for the L versions of S/X (Inconel contactors and pyro fuse), 3 is all the same bits.
voip-ninja
Give me some sugar baby
More than likely Tesla are sandbagging the performance in software.
The dual motor car likely has 500 horsepower front and rear, even in non P variants based on Tesla's claims of RWD output power vs. dyno results.
The Model 3 AWD should be as fast off the line as a BMW 340xi and MUCH faster once underway.
I'm hoping that Tesla uncorks it a bit more once they work through the backlog of deliveries.
A 340xi with the better Tesla handling and super charger network is quite exciting to me... as I'm already driving the 340xi and it's a blast, other than handling like a sled compared to the Tesla.
I find it interesting that with the 3, the AWD flavors get less range, whereas with the S, the AWD models got slightly more range, despite the extra weight.
The general attribution for the increased range was that the front motors on the S were geared slightly taller, and the car had the ability to "torque sleep" the rear motor when cruising, in effect shifting to the motor operating in a better efficiency range at higher speeds.
I wonder what is different with the 3. A couple of thoughts:
1) The motors are not geared differently if they are using the same gear reduction unit on both ends despite being an AC induction in the front. This may be being done for economies of scale from a manufacturing perspective.
2) The SWRPM motors don't have the same back-EMF characteristics such that the RPM shift accomplished by taller gearing didn't make that big of an impact.
3) It may not be practical to "torque sleep" a switched-reluctance permanent magnet (SWRPM) motor. Given that motors with a PM component tend to "cog" when freewheeling, this may prevent being able to do this smoothly. If so, this might prevent completely sleeping the rear motor. The front AC induction unit that may be the only one that can sleep.
I've seen some discussion that Tesla getting the power electronics capable of shaping the waveform to operate use a SWRPM motor in an automotive application was a significant feat. I've also heard someone say that when a model 3 is coasting without power, you can feel a little cogging.
I suspect that #1 is not as likely, and it may be some combination of 2 & 3...
The general attribution for the increased range was that the front motors on the S were geared slightly taller, and the car had the ability to "torque sleep" the rear motor when cruising, in effect shifting to the motor operating in a better efficiency range at higher speeds.
I wonder what is different with the 3. A couple of thoughts:
1) The motors are not geared differently if they are using the same gear reduction unit on both ends despite being an AC induction in the front. This may be being done for economies of scale from a manufacturing perspective.
2) The SWRPM motors don't have the same back-EMF characteristics such that the RPM shift accomplished by taller gearing didn't make that big of an impact.
3) It may not be practical to "torque sleep" a switched-reluctance permanent magnet (SWRPM) motor. Given that motors with a PM component tend to "cog" when freewheeling, this may prevent being able to do this smoothly. If so, this might prevent completely sleeping the rear motor. The front AC induction unit that may be the only one that can sleep.
I've seen some discussion that Tesla getting the power electronics capable of shaping the waveform to operate use a SWRPM motor in an automotive application was a significant feat. I've also heard someone say that when a model 3 is coasting without power, you can feel a little cogging.
I suspect that #1 is not as likely, and it may be some combination of 2 & 3...
ℬête Noire
Active Member
A simpler answer (though doesn't account for all of it); The front motor added to the AWD Model 3 variants is significantly less efficient than the rear motor. Thus combined efficiency will drop compared to the efficiency of the "pure" PM.
In the Model S front and back were similar/the same efficiency, because they were using the same technology. The benefit of increased traction outweighed the drawbacks.
You’re right, I forgot they built all of those things into the drive unit. Sounds like the AWD version is a pretty good deal.
I suspect you are right and that's part of it as well.
The increase in efficiency the 3 sees as a whole is understood to be in large part to the SWRPM motors.
I suspect that they went with AC induction up front partly in order to allow it to sleep...
Think of it this way:
The larger rear motor in RWD S/X was less efficient that the small rear motor on S/X AWD (even including drag from the extra front motor)
3 keeps the same rear motor, so the extra mechanical drag of the front motor (no electrical drag due to being AC Induction) reduces range.
Agreed... I was surprised it actually reduced range however... I was hoping that perhaps increased gearing ratio would have offset the lack of efficiency gains but not going to a slightly smaller rear motor, and perhaps kept range the same rather than getting an increase like on the S.
So I suspect not being able to sleep the rear motor may factor in.
Every electric motor needs a good nap now and then...
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