How do the AWD different motor types complement each other?

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#1
I am sure it has been talked about somewhere but I can’t find it. There has to be a reason for the induction motor in the front of the AWD. It is not efficiency. I assume the two types complement each other.

Does anyone know at what speeds each motor is most efficient? Will the induction motor warm the battery and the cabin faster?

I have heard it both ways that the switched reluctance motor jumps off the line then others have said it lacks the punch of the Model S induction motor. I have also heard that the switched reluctance does not over heat like the induction motor.
 

garsh

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#2
Some previous discussions on Tesla motor technology:

Tesla Electric Motor
dc motor vs ac motor

An article on the Tesla blog:
Induction Versus DC Brushless Motors

I'm curious to find out why Tesla is going with the two different technologies. There's not a *huge* difference between the two types of motors. Induction motors tend to be a little larger & heavier for the same power, but are less expensive to manufacture.
 
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#3
I'm also surprised induction motor is at the front.
I thought more powerful one would be at the back in case of spirited driving.
Induction motor is more about power less about efficiency.

Anyway, I do no consider dual motor version.
Also it appears induction motors are not as reliable as PM motors.
 

garsh

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#6
And most engines models are 10x+ more reliable than Model S drivetrain.
You made a general comment about induction motors (not Model S drivetrains) being less reliable. Now you're changing the argument.
 

John

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#7
I was under the impression that:

1. The base Model 3 switched reluctance motor is optimized for efficiency and cost and fairly good performance
2. The traditional induction motors favor performance and offer a side efficiency benefit of field shaping at high speed/low load, when other types of motors tend to have a back-EMF efficiency drop off.

So if someone is going to spring $5000 for an extra motor, the induction motor is a good choice for performance and as a highway-speed cruising efficiency aid.

Well, that's my impressions anyway.
 
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#8
It's a Tesla forum. By default, everything told here is about Tesla if not mentioned otherwise.
Be it induction motors made by Tesla or something else.
I definitely didn't mean induction motors used for water pumps.
Tesla's induction motors are not reliable, compared to, let's say Nissan's PM motors (no failures at all AFAIK).
Though often something else fails in the drivetrain, not specifically motor.
 

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#9
It's a Tesla forum. By default, everything told here is about Tesla if not mentioned otherwise.
Be it induction motors made by Tesla or something else.
I definitely didn't mean induction motors used for water pumps.
Tesla's induction motors are not reliable, compared to, let's say Nissan's PM motors (no failures at all AFAIK).
Though often something else fails in the drivetrain, not specifically motor.
that's a reasonable point to make, although reliability is not down to be being induction or PM, but down to quality of manufacture/design.
 
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#10
In case of motor problems, I've read years ago, that Model S did suffer
induction motor specific flaw of current passing through motor bearings.
Shaft voltage is the reason.
And we can categorize that as "design mistake". Not the same as quality.
 

garsh

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#11
It's a Tesla forum. By default, everything told here is about Tesla if not mentioned otherwise.
arnis, stop changing your argument. By that logic, your original statement:
Also it appears induction motors are not as reliable as PM motors.
Is completely non-sensical, because Tesla didn't even make a PM motor until the Model 3, and that hasn't been in service long enough to gauge reliability.

Tesla had some design issues with the Model S drivetrain. They've since fixed those, save for overheating when racing. But that is not a valid basis for asserting that PM motors are more reliable.
 

Scuffers

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#13
AFAIK 2017 Model S-X drivetrains are still not as reliable as they should be (on par with other EVs).

My argument is that using induction motor on Model3 might not be the best idea.
not sure that's a fair statement?

there are more Tesla motors out there (so bigger pool to fail) as well as their motors are at least double the output of every other maker's, so your not really comparing apples with apples etc etc.

be interesting to get the full stats on failures (in respect of the fleet numbers etc)
 
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#14
There are more than 300 000 Leaf in the world.
And about the same number of Model S's.
Though at least half of them have two motors.

Anyways... Failure rate is not slightly more.
Like I said, I've not heard of Leaf motor/inverter failure, at all.
And there are tens of thousands of failures with Tesla.
Some have 3-4 replacements.

Stats would be awesome.

PS:
Leaf motor has higher nominal power output than single Model S motor.
 
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#16
382hp is peak power. Not nominal. Nominal is around 100-200hp, those values are hard to find.
Easiest way to estimate is to analyze top speed. If it is below 155mph/250kmh, then nominal power
is less than 170kW/230hp.
147hp mentioned by Nissan is actually nominal power.
 

Scuffers

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#17
382hp is peak power. Not nominal. Nominal is around 100-200hp, those values are hard to find.
Easiest way to estimate is to analyze top speed. If it is below 155mph/250kmh, then nominal power
is less than 170kW/230hp.
147hp mentioned by Nissan is actually nominal power.
in the context, that's a meaningless metric.

Unless you have the full datasheet for each motor with their load/temp/etc characteristics?

As for numbers, how many cumulative miles do you think all those Leaf's have covered compared to the Model S's?

I bet most never do more than short commutes etc, and are second/third cars.
 
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#18
As for numbers, how many cumulative miles do you think all those Leaf's have covered compared to the Model S's?

I bet most never do more than short commutes etc, and are second/third cars.
Leafs have travelled 3 billion km-s by the end of 2016. Teslas 8 billion km-s by the summer of 2017.
Therefore annual mileage is really close. Long commutes is a tiny fraction of total miles travelled.

I do not have full specsheet for every version but I can browse registrational data for random Teslas that are on sale. And there I can see real nominal motor power.
 

Scuffers

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#19
Leafs have travelled 3 billion km-s by the end of 2016. Teslas 8 billion km-s by the summer of 2017.
Therefore annual mileage is really close. Long commutes is a tiny fraction of total miles travelled.

I do not have full specsheet for every version but I can browse registrational data for random Teslas that are on sale. And there I can see real nominal motor power.
In what universe is that 'really close'?

Look, you go live in your delusional world, I'm out.
 
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#20
In what universe is that 'really close'?
In the order of magnitude "really close".
All Leafs 3 billion km: <100 failures.
All Teslas 8 billion km: >100 000 failures (more than half of driveunits up to some point).
It's in the order of magnitude "really close".

Look, you go live in your delusional world, I'm out.
You are not the first one who's out, #Brexit