Carbon wrapped rotor motor…

[ldjessee]

I am hoping it will become the normal, but could see it being only on the ‘performance’ models…

What do others think about any of the tech from the S Plaid to come to the Cybertruck?

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[Crissa]

It's implied to be the motor in the Tri Motor.

-Crissa

 

[CyberMoose]

I am hoping it will become the normal, but could see it being only on the ‘performance’ models…

What do others think about any of the tech from the S Plaid to come to the Cybertruck?

Hard to say. The new motors might not be put on anything except the Plaid versions of Tesla vehicles. Meaning it's quite possible that only the Model S Plaid, Model X Plaid, and Plaid Cybertruck will get this.

When we look at other differences between the Plaid trim vs other trims on the Model S. It seems to be only performance based. I don't think the Plaid has any other benefits over the other trim levels. The new refreshed look for the Model S applies to all of the trims, but Tesla first showed them off when they were delivering the new Plaid vehicles.

I think the real question would be what sort of features will we see from the luxury side of Tesla (S/X) in the Cybertruck. I'm hoping the Cybertruck becomes another luxury vehicle for Tesla, as well as the work horse that everyone knows it can be. I'm personally hoping for the built in gaming computer, since once we get FSD, I'd love to dominate my friends in some games on long drives. I am also hoping for ventilated seats and a similar back seat arm rest to the S/X.

The only thing I found missing on the Cybertruck from photos is wireless phone chargers. The long slanted surface infront of the cup holders on the middle front seat could definitely be partitioned into two wireless phone chargers, so maybe they'll put them there.

 

[ajdelange]

The main motivation for the copper rotor motor is evidently the high cost of the rare earth metals required for the permanent magnets in the synchronous motors. Tesla (and other) OEMs had been migrating towards the PMSRMs because they are more efficient but it looks as if they are going back to CRIMs (Copper Rotor Induction Motor) because of cost. The carbon wrapping makes for a more efficient motor as it can be turned much faster without flying apart so evidently some of the efficiency loss has been recovered. Note: these comments are based on what seems reasonable. I have not seen any engineering information on Tesla's CRIMs.

It has been widely supposed, which does not make it true, that the Plaid S was a sort of a test bed for the CT. The back end of the CT may not be the same back end that is in the S but I think it will have a pair of CRIMs .

 

[Diehard]

I think new heat pump will make it to CT.

As for motor, I am clueless about metrics and how the tech stacks up against others but my priorities are:

1 - Reliability
2 - Range
3 - Performance

2 and 3 may be related but you know what I mean. If Carbon wrapped rotor more likely to explode earlier, I would be OK to get something more reliable with slightly less towing and acceleration.

 

[JBee]

One of the main reasons for doing the CF rotor wrap is to increase the rpm. More rpm means more power out of a smaller and lighter package.

As Adjelange pointed out, going with a IM instead of PM also makes it cheaper as well, and less resource sensitive. They would have found some more efficiency in the IM with CF wrap and closing the airgap, probably along with square cable windings (instead of round core cable) or hairpin coils (like others use to improve eff.). They also might have some improved ESC switching etc.

Theres also likely to be an improvement in the HVAC and motor/battery cooling as well. Technically, they could have found enough efficiency gains in the HVAC and cooling alone to make IM get close to the PM eff.

But in regards to the MS plaid i believe by far the most range gained, despite the other gains above, was by the much improved aero Cd of 0.20.

Primary drivers for most companies is cost reduction whilst maintenaining or improving performance and longevity. Theres an old addage you can't have everything, but that never stopped anyone trying.

But in this case I'm presenting this because I believe that the new IM will be the defacto motor for the CT and possibly Austin and Berlin MYs too. The reason is because if they made the effort to streamline and improve IM, and can do so at a cost equal or better than a PM, then its worth them investing in custom manufacturing equipment so they can cut the cost in all of their models, and not be caught up in a race against other manufacturers for rare earth magnets. Copper is much easier, even with a CF wrap, it would seem.

The other thing that leads me to believe this is that all 3 plaid motors look identical in the photos, theres some cost savings to be had for making one motor that can drive any vehicle, and any combination of RWD, AWD or TM as well. At some point even with a IM you can reach enough overall performance, and efficiency, that you no longer can put that down on the road through a tyre. I think the plaid driverrain is reaching that point now already, and wthat is why the Plaid + was cancelled. Unlike ICE where engine performance is very costly, in a electric it not the case, and a optimised low cost motor can and will reach traction limits.

And that brings us to the carbon wrapped IM in a CT. The same logic applies, its just we'll likely see a higher gear ratio final drive on the CT. But the same motor and ESC. Along with the same HVAC.

 

[rr6013]

I am hoping it will become the normal, but could see it being only on the ‘performance’ models…

What do others think about any of the tech from the S Plaid to come to the Cybertruck?

20,000 rpm is trucking ridiculous!

Tesla can regear to the higher rpms enjoy more torque-y traction or software regulate the Plaid carbon wrap self-limiting the performant tech.

Its waste on a truck unless there are range-y reasons or miracle battery magic to be had.

Cooling @Diehard called it “in” for the win. Huge battery saver!

Big question are you OK with 18650’s new chemistry powering Cybertruck if 4680 aren’t up to speed by 4/22 SOP? That’s on the table.

 

[ajdelange]

20,000 rpm is trucking ridiculous!

No, not at all. Torque depends on current. Loss depends on current. Power is the product of torque and shaft speed. Same current, same torque, same loss. Higher rotor speed at same torque means higher power at same current and thus higher power per unit of loss. This means more efficiency. Sounds like a good idea to me!

Tesla can regear to the higher rpms enjoy more torque-y traction or software regulate the Plaid carbon wrap self-limiting the performant tech.

I have no idea what that sentence is trying to say.

Its waste on a truck unless there are range-y reasons or miracle battery magic to be had.

The magic is higher efficiency and that means more miles on a charge.

 

[Diehard]

Big question are you OK with 18650’s new chemistry powering Cybertruck if 4680 aren’t up to speed by 4/22 SOP? That’s on the table.

At this point any powertrain would do as long as I get it before I kick the bucket. Anything from T2 (Liquid Metal Battery) CT to foot-powered CT would do.

 

[ajdelange]

I think new heat pump will make it to CT.

It will definitely have a heat pump (all Tesla models do) but I expect this to be bidirectional i.e. the Octovalve or a derivative of it will be part of the CT.

 

[Jhodgesatmb]

During the presentation they said the need for the carbon-wrapped rotor was so the rotor could survive the huge speed range required of the plaid Model S. The CT will not have the same top end so carbon wrapping, which I am sure is expensive, would probably be overkill.

 

[JBee]

The other "simplified way" to look at it is by comparing rpm on a ICE. F1 cars get some 1100hp from a small 1.6l by running it at 15000rpm. A LM1 (350 Chevy) with 5.7l won't even do half that.

In the case of the CT I was always pretty confident we were going to get a IM in the back at least, just from a cost perspective, but obviously didn't know Plaid was going to go all out CRIMs.

At some point it also becomes cheaper and easier to add some more battery to get the desired range, rather than spend a fortune on that last 1-2% of motor efficiency.
For example if you have 100kWh pack, adding 2kWh to the pack, and not telling anyone, won't matter to the usability of the car, and only increase the price a few hundred dollars too (if that).

I think we'll see more of that happening as battery costs come down. The value proposition curve changes with batteries becoming more affordable, so motor efficiency becomes less important than when they were expensive (and rare).

 

[ajdelange]

During the presentation they said the need for the carbon-wrapped rotor was so the rotor could survive the huge speed range required of the plaid Model S. The CT will not have the same top end so carbon wrapping, which I am sure is expensive, would probably be overkill.

The high rotor speed is desired in the CT too as it implies greater efficiency. No, the CT won't have the same top speed but whatever its top speed is it will be at 20,000 rpm. The motor will just be geared down more for the lower CT top speed.

 

[JBee]

During the presentation they said the need for the carbon-wrapped rotor was so the rotor could survive the huge speed range required of the plaid Model S. The CT will not have the same top end so carbon wrapping, which I am sure is expensive, would probably be overkill.

Could well be overkill to reach CT top speed, but its also allowing a smaller gap, and improving efficiency, reducing costs etc as described above. They will also be using a higher gearing to improve torque for towing etc on a CT, typically a smaller can motor will also produce less torque, so they'll need some rpm to get there on a Ct.

I also don't think the cost of CF itself per motor is a main factor, i dare say its in the specialised machinery they built that needs to be paid back...hence the reasoning to make more models use that type of motor.

 

[ajdelange]

I still think people are missing the point that they want the maximum power at the minimum current. This is acheived by maximizing the rotor speed. You also have to increase the voltage, of course. They will spin the CT motor at as high a speed as they can and gear it to so that the wheels are going at the top vehicle linear speed at that motor rpm.

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