PMAC vs induction motor for model 3

[stopcrazypp]

Interesting. That does seem pretty definitive, however unexpected. Also note the city/highway break - 131 city, 120 highway, 126 combined. Most Teslas to date have higher freeway than city...

Yeah, with the switch to PMAC and the car being much lighter, the Model 3 is going to share a lot more similarities with other existing EVs (including being more efficient in the city).

However, the relative efficiency still matters. here's how the 3 compares to the most efficient EVs in the market:
Combined / City / Highway
Ioniq Electric: 136 / 150 / 122
Model 3 (LR): 126 / 131 / 120
i3 (60 Ah): 124 / 137 / 111
Bolt: 119 / 128 / 110
Spark EV: 119 / 128 /109
e-Golf: 119 / 126 / 111
i3 (94 Ah): 118 / 129 / 106
Leaf (24 kWh): 114 / 126 / 101
Leaf (30 kWh): 112 / 124 / 101
i-MiEV: 112 / 121 / 102
fortwo electric coupe: 108 / 124 / 94
Focus Electric: 107 / 118 / 96
Soul Electric: 105 / 120 / 92
Model S 90D: 104 / 102 / 107

I think this bodes well for highway efficiency, since the trajectory is that it looks like it's likely to beat the Ioniq at more realistic highway speeds (given how much higher the city rating is, the Ioniq is likely far more city optimized than the Tesla).

 

[stopcrazypp]

It has been clear to me for quite some time, that Tesla will switch to PMAC as their main motor in the Model 3, maybe even all of their future vehicles, so this wasn't a surprise to me. My comment was more tailored towards those who kept arguing against the EPA document, because of a spelling error.

IMO the induction motor has it's place, maybe even more so in the future. And I could imagine them adding an induction motor to their AWD setup. The PMAC is just too efficient and too power dense not to use it, especially in a environment where range is king and the battery is the most expensive single part of the vehicle.

Actually induction motors are easier to handle in many aspects, than PMAC. So given Teslas reliability record, they better tried a lot harder.

You can make anything reliable and durable, but that means quality control and going the extra mile in testing. Tesla as I see it seems to live more in the future, than the present, which could be an issue.

But I think they also hired lot's of good established engineers from bigger OEMs to help them out when it not only comes to making a good product, but that product also staying a good product for a long time.

Given how Tesla has kept completely quiet about this however, I'm not sure Tesla is particularly proud of this. As argued up thread, it kills the argument that Tesla cars are unique in not using rare earths in their motors. And it drops one of the connections with the "Tesla" name.

It might not matter to a lot of general buyers (they probably don't even know about the different types or care other than for the rare earth argument), but I'm sure there are fans that are somewhat disappointed. Hopefully there are efficiency/cooling advantages to make up for this.

 

[gregincal]

Given how Tesla has kept completely quiet about this however, I'm not sure Tesla is particularly proud of this. As argued up thread, it kills the argument that Tesla cars are unique in not using rare earths in their motors. And it drops one of the connections with the "Tesla" name.

It might not matter to a lot of general buyers (they probably don't even know about the different types or care other than for the rare earth argument), but I'm sure there are fans that are somewhat disappointed. Hopefully there are efficiency/cooling advantages to make up for this.

I doubt they've even heard about the rare earth argument. Generally only people looking for reasons to hate EVs or ardent defenders ever talk about it. Nobody else cares.

 

[R.S]

Yeah, with the switch to PMAC and the car being much lighter, the Model 3 is going to share a lot more similarities with other existing EVs (including being more efficient in the city).

However, the relative efficiency still matters. here's how the 3 compares to the most efficient EVs in the market:
Combined / City / Highway
Ioniq Electric: 136 / 150 / 122
Model 3: 126 / 131 / 120
i3 (60 Ah): 124 / 137 / 111
Bolt: 119 / 128 / 110
Spark EV: 119 / 128 /109
e-Golf: 119 / 126 / 111
i3 (94 Ah): 118 / 129 / 106
Leaf (24 kWh): 114 / 126 / 101
Leaf (30 kWh): 112 / 124 / 101
i-MiEV: 112 / 121 / 102
fortwo electric coupe: 108 / 124 / 94
Focus Electric: 107 / 118 / 96
Soul Electric: 105 / 120 / 92
Model S 90D: 104 / 102 / 107

I think this bodes well for highway efficiency, since the trajectory is that it looks like it's likely to beat the Ioniq at more realistic highway speeds (given how much higher the city rating is the Ioniq is likely far more city optimized than the Tesla).

It would make sense that FWD EVs have a better city efficiency, since they can recuperate better. The Model 3 might be more limited in that regard. So that could be a reason for the low city/highway difference. The car is also still heavier than most others, which means a lot in city driving.

It will be interesting to see the SR MPGe, since that is a much lighter car. Or the LR AWD MPGe. Who knows how those motors are set up efficiency wise.

Given how Tesla has kept completely quiet about this however, I'm not sure Tesla is particularly proud of this. As argued up thread, it kills the argument that Tesla cars are unique in not using rare earths in their motors. And it drops one of the connections with the "Tesla" name.

It might not matter to a lot of general buyers (they probably don't even know about the different types or care other than for the rare earth argument), but I'm sure there are fans that are somewhat disappointed. Hopefully there are efficiency/cooling advantages to make up for this.

The "no rear earth magnets" slogan was cool, but if you look a bit more closely at especially cobalt for the batteries, or the aluminum body, the little bit of NdFeB isn't the worst offender. The connection to the Tesla name is getting lost, that's true, but Ferrari also doesn't use induction motors, even though Ferraris was the first one to build a one phase induction motor and Dolivo-Dobrovolsky was the first to build a three phase induction motor and it's still called Tesla motors.

Tesla is also the unit of the magnetic B-field, which is still the driving force of any electric motor. So it kinda still works.

And the induction motor wasn't like Porsche's air cooled boxer six cylinders. You won't notice the difference, once they change to PMAC.

 

[SageBrush]

here's how the 3 compares to the most efficient EVs in the market:

One more data point, the very efficient Prius Prime raw two cycle data:

EV Mode

1. City: 16.26 kWh/100 miles
2. Highway: 19.52 kWh/100 miles

If you figure that the MPGe is 70% of the raw two cycle results the figures work out to
City: 0.7 * 33700/162.6 = 145.08 MPGe
Highway: 0.7*33700/195.2 = 120.85 MPGe

 

[SageBrush]

here's how the 3 compares to the most efficient EVs in the market:

Arranged by Highway MPGe:

 

[scaesare]

They did.

I believe you can see it on the motor tear down done by EVTV for those interested...

 

[McRat]

Interesting. That does seem pretty definitive, however unexpected. Also note the city/highway break - 131 city, 120 highway, 126 combined. Most Teslas to date have higher freeway than city...

Some folk expected it.

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

 

[Fred Thompson]

I remember Elon saying in a video interview, not to long ago, that the rear motor is designed more for city driving and the front motor designed more for highway driving for the dual motor setup. I can't remember where he was doing the interview. With the front motor designed more for highway driving, the MPGe should increase withe the dual motor option.

 

[JRP3]

It would make sense that FWD EVs have a better city efficiency, since they can recuperate better.

I don't think so at city speeds, rear wheel regen is likely at the same level for all but possibly extreme deceleration events, which are rare.

 

[Zoomit]

I don't think so at city speeds, rear wheel regen is likely at the same level for all but possibly extreme deceleration events, which are rare.

This is correct. It is commonly thought that RWD is able to regenerate less, but that's not true unless the rear tires lose traction. There are cases when that can happen, but as you said it is rare. RWD Teslas and i3s have perfectly acceptable regen.

 

[alloverx]

Should someone ask Elon on twitter about Model3 and rare earth mineral usage?

 

[stopcrazypp]

Should someone ask Elon on twitter about Model3 and rare earth mineral usage?

A couple people asked about if Model 3 used an induction or permanent magnet motor and he didn't even respond to that. It's even less likely he will respond to a question like that.

 

[SageBrush]

Should someone ask Elon on twitter about Model3 and rare earth mineral usage?

Someone: Elon, does the Model 3 use rare earth metal magnets ?
Elon: Yes
Someone: Is it a problem ?
Elon: No, but if that changes we have induction motors too.

 

[SageBrush]

My earlier graph converted to EPA highway miles per battery kWh, since it makes a lot more sense to me than MPGe

 

[cronosx]

This is correct. It is commonly thought that RWD is able to regenerate less, but that's not true unless the rear tires lose traction. There are cases when that can happen, but as you said it is rare. RWD Teslas and i3s have perfectly acceptable regen.

Realistically speaking the rwd and awd are ABSOLUTELY THE SAME on regen capacity, since the grip is based on the discharge power of the battery wich is far lower than the capacity of the battery to charge.
It's a common misconception based on the fact that the brake are more strong on the awd due to grip factor, but in reality the regen is like a soft brake not a "full power brake"

 

[wycolo]

What makes them (3) so good??
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[transpondster]

What makes them (3) so good??
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coefficient of drag of 0.24 0.24 0.23

 

[McRat]

What makes them (3) so good??
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The Prime doesn't belong in that list since it's normally a gas powered car. It needs the gas engine to achieve sub 12 second 0-60 mph times. ie - 79% of all trips require a the gasoline engine to run. This is higher than 45% for the CMax and Fusion PHEV and on a far lower tech level than the 11% that a Volt needs gasoline power.

https://www.arb.ca.gov/msprog/acc/mtr/appendix_h.pdf see Fig 7, yellow bars to the right.

Now, if you don't use selective calculation, the Volt uses 14.1 kWh to reach 49 miles EV highway range per EPA, which is 3.475 miles per kWh and it will accelerate to 60 mph in 7.5s in EV mode and go 101 mph. The Volt holds a far higher reserve level on the battery because it has a less powerful gasoline engine, hence needs to use battery to deliver full rated HP when the gas engine is being used.

Instead, you list one of the major engineering mistakes of the Prime when used as an EV as a valuable asset.
With it's gas-first technology and small electric motor, it's only gets good EV efficiency 21% of the trips you travel. The other times it gets terrible EV efficiency.

 

[wycolo]

Did not realise that the Ionique is a ground-hugging sedan. But then the S 90D is degraded solely for its induction motor?

Beware, a fully-graphed life might not be worth living . . .
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