PMAC vs induction motor for model 3

[nwdiver]

If you check out the following certification documents the MS and MX are listed as using AC Induction motors while the M3 is listed as using a 3 Phase Permanent Magnet motor:

Model 3: https://www3.epa.gov/otaq/datafiles/CSI-HTSLV00.0L13.PDF

https://www3.epa.gov/otaq/datafiles/CSI-HTSLV00.0L1S.PDF
https://www3.epa.gov/otaq/datafiles/CSI-HTSLV00.0L2SV2.PDF
https://www3.epa.gov/otaq/datafiles/CSI-HTSLV00.0L2XV3.PDF

Odd... I would be interested in what drove that choice... AC induction motors are so ubiquitous; It's a proven technology that's efficient and robust. It would appear that PM motors are slightly more efficient and require less cooling especially from the rotor since there's no current there with a PM rotor. I would be concerned about the longevity of a PM rotor since PMs can be rather brittle compared to copper... I wonder if this is why the 3 no longer has an unlimited mile warranty...

So much for 'Tesla doesn't use rare earth metals' Although 'rare earths' aren't really 'rare'. IIRC cobalt for the battery is more scarce than any rare earth metal.

 

[McRat]

This is very good news indeed. More miles per kWh, more regen, less weight.

 

[03DSG]

If this is not a typo then it's directly in line with the rumors from last year about permanent magnets from China.

also... check out the "Charge Depleting Range (Actual miles)" (granted it's on a dyno so there's no wind resistance)

it also mentions SOC 78270 Wh so that solves that question

Jeff, I doubt its a typo on a certification document. This has been rumoured for a while.

 

[JeffK]

Jeff, I doubt its a typo on a certification document. This has been rumoured for a while.

Yes, that's what I said.

 

[anticitizen13.7]

Tesla's take on this from 2007 is that both types of motor are useful depending on design requirements:

Induction Versus DC Brushless Motors

tldr; use Induction for performance and cost reasons, use Permanent magnet for efficiency and better thermals.

 

[anticitizen13.7]

Model 3 has an effective MPG of 126 • r/teslamotors

Model 3 Long Range window sticker says 126 MPGe.

Model S 75 RWD sticker for comparison is 98 MPGe.

The 28.5% better efficiency in favor of Model 3 is unlikely to be due to weight and aero alone. This is strong circumstantial evidence for a change in motor type.

I suspect Tesla will use induction motors for performance cars and permanent magnet in more mainstream vehicles.

 

[omgwtfbyobbq]

Someone on reddit pointed out that the 3 has "Both" under regen brake source, like an AWD Tesla.

Regenerative Braking Type - Electrical Regen Brake
Regenerative Braking Source - Both

If that's not a typo, Tesla might have something for regen up front, which could account for the relatively small (to me) frunk and amazing handling.

 

[MP3Mike]

I suspect Tesla will use induction motors for performance cars and permanent magnet in more mainstream vehicles.

Or maybe they will start to use both in the performance cars: a large induction motor in the back, and a smaller permanent magnet motor in the front for cruising. (They already use different gear ratios front/back.)

 

[ratsbew]

This is very, very interesting. Optimizing for the lowest possible consumption per mile allows them to cut costs on the battery by having a smaller pack for a given range.

I wonder if they will offer a Long Range Model S that uses PM motors and the 100kWh pack? I don't care much for performance and would happily have a 6.0 second Model S that can do 350+ miles per charge. The effective supercharging rate goes up too with increased efficiency.

 

[stopcrazypp]

If this is not a typo then it's directly in line with the rumors from last year about permanent magnets from China.

also... check out the "Charge Depleting Range (Actual miles)" (granted it's on a dyno so there's no wind resistance)

it also mentions SOC 78270 Wh so that solves that question

That's the usable. Spec also says battery voltage 350 and capacity 230 which works out to 80.5 kWh nominal.

 

[R.S]

It's kind of funny to read through the old posts. One very nice example:

But no, they won't be switching to permanent magnet motors -- ever -- because their own technology is simply BETTER. At least, in all the ways that matter most to their Chief Product Architect, Elon Musk and his Chief Technology Officer, JB Straubel.

These old threads are gold!

 

[ikjadoon]

Or maybe they will start to use both in the performance cars: a large induction motor in the back, and a smaller permanent magnet motor in the front for cruising. (They already use different gear ratios front/back.)

This document states it's 2-Wheel Drive, RWD only, which we expect from any EPA certifications in July.

My pet theory: it's either a typo or they've included a small generator that connects the front axle to the battery: it might easier to switch to AWD (just switch the generator for a proper motor, as all Model 3s are wired up already).

 

[nwdiver]

Tesla's take on this from 2007 is that both types of motor are useful depending on design requirements:

Induction Versus DC Brushless Motors

tldr; use Induction for performance and cost reasons, use Permanent magnet for efficiency and better thermals.

It's still a 3-phase AC motor... it just uses permanent magnets in the rotor instead of shorted copper wires and an induced magnetic field.

 

[TEG]

 

[R.S]

The Best Electric Vehicle Motor

An article quoting wikipedia as their only source.

Also riddled with mistakes, that article.

 

[mrkisskiss]

Intrigued to read that Tesla uses a permanent magnet motor in the Model3, as opposed to the induction motor in the S and X

You'd have thought that the higher cost of the permanent/rare earth magnet motor vs the induction motor - plus their existing R&D expertise and hardly-ever-need-servicing advantages would have led them to keep the same induction style motor...

I guess they decided the efficiency gain of the permanent magnet motor was worth the extra hassle, weight and cost?

Interested to hear from someone who knows about these things....

 

[Thomas Edison]

Intrigued to read that Tesla uses a permanent magnet motor in the Model3, as opposed to the induction motor in the S and X

You'd have thought that the higher cost of the permanent/rare earth magnet motor vs the induction motor - plus their existing R&D expertise and hardly-ever-need-servicing advantages would have led them to keep the same induction style motor...

I guess they decided the efficiency gain of the permanent magnet motor was worth the extra hassle, weight and cost?

Interested to hear from someone who knows about these things....

There's an ongoing discussion about this here:
PMAC vs induction motor for model 3

 

[No2DinosaurFuel]

Looks like I am vindicated in my prediction. For those who doubted me, now I can say "told you so!"

Now if only they put the PMAC into the Model S with a 120KWh battery pack, I wouldn't be surprised if it can do 400 EPA miles at the cost of performance, but still quite fast if it was AWD.

 

[JeffK]

Looks like I am vindicated in my prediction. For those who doubted me, now I can say "told you so!"

There's even a thread for that I told you so!...

 

[Cosmacelf]

Interesting stuff: New Tesla Model 3 details revealed by EPA: ~80 kWh battery pack, 258 hp, and more