Model 3 using different motor technology?

Model 3 using different motor technology?

Chargedmr2 | 6 august 2017

Just saw this. Curious what the implications are? Also, wonder if a P version would use the same?

gavinmcc | 6 august 2017

I always figured the 3 was going to use a smaller motor...smaller car and isn't made to go 0-60 in 3 seconds. 3 will never beat the S in speed...Tesla won't allow it.

As for the technology, yeah, that will keep moving forward. Motor will become lighter and more efficient...hopefully finding ways to improve performance and longevity while also losing or limiting rare earth materials...great times, greater times ahead...


Sandy’s 3 | 6 august 2017

Its clear they are changing. You can see the motor description at the bottom left of page 3.

Model 3: AC 3 Phase Permanent Magnet motor
S+X: AC Induction motor

Rutrow | 6 august 2017

3 phase AC is going to be a more efficient motor and lighter weight since it won't have to have starter windings, but a permanent magnet motor won't be able to eliminate regen voltage when the battery is full. There'll have to be some other way to bleed excess energy to prevent overcharging.*

*I'm not an engineer and have only a little understanding about motors.

Coastal Cruiser. | 6 august 2017

Thanx FLHX13! The motor tech is fascinating to me, and I've been wondering what would show up in the M3. There have been rumors for some time that the motor would be a permanent magnet variety, and those PDFs affirm such. Here is what I think can be safely said...

1) The Model 3 motor is NOT an induction motor. They are breaking away from the Nikola Tesla design (not saying this is 'good' or 'bad', just saying).

2) Like the Model S/X the Model 3 motor is still a 3 phase AC design. But rather than 'inducing' a current to flow on the rotor they are affixing magnets (probably rare earths) to the rotor to create the required opposing magnetic fields that force the rotor to spin.

3) As best I understand, the advantage of the permanent magnet version is less heat. The rotor (the spinning part that drives the wheels) will run cooler, thus the motor itself will run cooler, thus perhaps less cooling infrastructure required (last part of that is my conjecture).

Here is an article on how the Tesla induction motor works:

Coastal Cruiser. | 6 august 2017

"but a permanent magnet motor won't be able to eliminate regen voltage when the battery is full. There'll have to be some other way to bleed excess energy to prevent overcharging.*

Interesting Rutrow. Can you explain how they eliminate regen in the induction motor? I don't know about that.

rajalucy | 6 august 2017

permanent magnet motor last longer

Sandy’s 3 | 6 august 2017

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.

Chargedmr2 | 6 august 2017

I liked that Tesla didn't use rare earth metals. Give their environmental focus, I hope they write a blog post discussing their choice and potential impacts as they see them.

johnse | 6 august 2017

Brakes bleed excess energy...just like the X/S in the same situation. Motor will generate voltage because of the magnetic lines of force passing through the motor windings, but if you don't provide a path for current to flow, there will be no braking effect from the motor, and thus no need to dissipate "excess" electrical power.

Or, if you wanted to save the brakes, you could dump the power into resistors, causing heat... but the brakes are there already, so why add complexity?

Also, permanent magnet motors can provide regen down to zero.

ReD eXiLe ms us | 6 august 2017

My guess is that the obvious typographical error puts the whole notion of Tesla using permanent magnets in their motors in question. On page 3, in a section labeled "Hybrid Electric Vehicle And Fuel Cell Information" there is a line for:

Motor/Generator Type 1 | AC 3 PHASE PERMENANT MAGNET | Rated Motor/Generator Power | 192

Someone may have simply chosen the incorrect option for a drop down menu before saving the PDF file, or simply typed in the wrong information. Because 'PERMENANT' is not the correct spelling for 'permanent' at all. I suspect the 192 is kW, not horsepower. So, the mechanical equivalent of about 257.476 hp. Not the 300+ I was hoping for, considering the rating for Model S 60, but it'll do against the given competition among 'entry level luxury' vehicles.

There is also the fact that Elon Musk and JB Straubel have been rather adamant that AC Induction, and avoiding the use of any form of 'rare earth metals' in the construction of their cars is imperative, makes me feel that form is not correct. I could find no publicly accessible means of getting to those PDF files. Why are they on a 'www3' server instead of a 'www', anyway?

Frank99 | 6 august 2017

This is disappointing. I'm surprised that they'd go the permanent-magnet route with all the problems associated with rare earths over the last several years.

Shygar | 6 august 2017

How do you feel about the neodymium magnets in the speakers?

carlk | 6 august 2017

I too thought not using rare earth permanent magnet is a plus. Still hoping it was just wrong info being put in that test sheet.

Rutrow | 6 august 2017

Coastal, *** I'm not an engineer, but my understanding about induction motors is that since they require current to induce the magnetism needed to impel the rotor, opening the induction circuit eliminates the field to allow the rotor to rotate without generating regen current. Permanent magnet motors cannot shut of the magnetic field, so if the windings of the rotor are spinning in this field, there will be current being generated. Since I have NO idea how voltage regulators work i hesitate asserting that voltage regulators would save the battery pack even when regen braking is slowing the car. The traditional cars I'm familiar with use voltage regulators to prevent the alternator from over-charging their lead-acid battery, so I would think that Tesla could use them, but apparently Tesla turns regen braking off when the battery is full. If the solution was inserting a voltage regulator Tesla could use them to shunt excess voltage away from the battery when overcharging would be a problem.

Are there any smart people out there who can rid me of my ignorant confusion?

slasher0016 | 6 august 2017

The TMC post is interesting, but there's no way it's doing 0-60 in 5.1 secs with only 258hp at nearly 4k weight.

carlk | 6 august 2017

Don't get too hang up on the horsepower number. Because of different torque curve EV's horsepower rating tends to underestimate its acceleration ability compares to ICE's at the same (maximum) hp rating. That's why the saying horsepower sell cars but torque win races.

Sandy’s 3 | 6 august 2017

slasher, It doesn't do it on HP. It does it on 100% instant torque.

Shygar | 6 august 2017

Just curious, how would you even get to the situation where you would potentially be regenning on a fully charged battery? For you to get up to speed to then slow down, you would be using more energy than you would gain back through regenning. Maybe if you charged up on top of a hill then proceeded downhill for a ways.

SUN 2 DRV | 6 august 2017

Rutrow: "Are there any smart people out there who can rid me of my... confusion?"

See johnse's reply which covered all the bases very well.

- Voltage yes, current (and braking) only if you want it.
- Permanent magnet motors can deliver regen even at low speeds.

Frank99 | 6 august 2017

>>>How do you feel about the neodymium magnets in the speakers?
Speakers aren't vital to sustainable transport. | 6 august 2017

@johnse posted the following thread last November with lots of clues supporting the permanent magnet option:

The M3 motor is rumored to be more efficient than its predecessors. Also, it should be lighter.

Frank99 | 6 august 2017

Thanks for the link, george. it's good to see that I didn't say anything stupid back then that would come back to haunt me...

gavinmcc | 6 august 2017

Shygar: yes, people who live uphill from work, stores etc...if they fill battery to 100% and then head to work and there is regen braking, it could over charge the battery...

It is unusual, but some people live up some pretty big hills. When I travel to the top of Sandia Mountain here in Albuquerque from my house, I can get to the top with only 35% of my. Artery and still know I can make it home because I regen on the way if I lived up the mountain I would never want to fully charge at home...


gavinmcc | 6 august 2017

my. artery should be my battery

But since a) I work in pediatric cardiology and b) I ride an electric vehicle about 365 days a year, my battery and my artery could be used interchangeably


johnse | 6 august 2017

Thanks for the memory, George. I had forgotten how much discussion had occurred there.

Coastal Cruiser. | 6 august 2017

"Thanks for the link, george. it's good to see that I didn't say anything stupid back then that would come back to haunt me..."

Yeah. You didn't say anything stupid. Did I say anything stupid?


So hear we are with a significant change in a critical piece of the skateboard. It all started with Alan Cocconi of AC propulsion, with the AC induction motor that inspired the Roadster. Yes, another case of someone's name being linked to their trade.

And who knows what they did to the inverter.

I am really set back by this revelation. Just loved the cleverness of the induction motor. However, all is not lost. One can still claim that inductive processes are in play on the Model 3 however... The NFC based keycard.


JayInJapan | 6 august 2017

Interesting change. If they are using rare earth, it's important to point out they're not rare at all. Our planet is loaded with them.

Coastal Cruiser. | 6 august 2017

By the way - we do have to face the fact that the Model 3 uses the same motor design as the Chevy Bolt.

Rocky_H | 7 august 2017

I'm surprised how many of you are buying this.

@Red Exile +1

I'm going with Red on this. Having the EPA as a "source" that Tesla is using a type of motor that they have been firmly against for a long time seems like a pretty high level of credulity. I won't do it. I think it's far more likely that they made a mistake in those documents. Goodness knows we've seen plenty of other organizations get things wrong about Tesla before.

reed_lewis | 7 august 2017

HP is a very useless number and means nothing in most cases. OTOH torque is a useful number that actually represents the 'pull' you feel when accelerating.

Horsepower represents that amount of that power you can apply in a time period.

I am always more interested in torque, because you can feel it.

Rutrow | 7 august 2017

ReD and Rocky, so do y'all think the big NdFeB magnet purchase was for the speakers?

ReD eXiLe ms us | 8 august 2017

Rutrow: I have no knowledge of any such thing.