Max. Torque meaning

Juergen

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#1
In the PDF owner manual is Tesla writing about maximum torque.
The number is 3700 Nm! That’s a lot.

F9E01405-7D05-4F86-BAC4-63B101AEFBAC.jpeg

The new Nissan Leaf have „only“ 320 Nm.


E64FCD17-AC5C-4AED-AC8F-E4BC8CAE0D6E.jpeg
Why have Tesla 11 times more torque?
Have Tesla multiply the motor torque with the gear ratio 9:1?

Jürgen
 

3V Pilot

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#3
Okay, so this brings me to a question that I have yet to figure out. What is the torque of the motor in regular Foot-Pound measurements? I'm just curious to compare it to other specs. Even though I know having 100% torque available at zero RPM is different than an ICE engine that has to build up RPM to get there I'd still like a reference point to compare.
 

Juergen

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#4
OK! Isn’t nice. Which other car maker do this also?
Is like compare the cw value from the semi with the Bugatti without talking about the frontal area.
The air resistance is the product of cw-value and frontal area.
It’s only marketing!
 

MichelT3

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#7
:eek::eek::eek:Calling foot-pound 'regular'??? Everything non-decimal (EDIT: non-metric) is irregular (non-regular) by definition.:D
You may not be used to it, but Nm is the international standard unit.
 
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3V Pilot

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#8
According to Motor Trend, the Model 3 LR measured at 307 lb-ft (not ft-lb):
http://www.motortrend.com/news/tesla-model-3-2018-car-of-the-year-finalist/
Thanks, that is exactly what I was looking for!

:eek::eek::eek:Calling foot-pound 'regular'??? Everything non-decimal is irregular (non-regular) by definition.:D
You may not be used to it, but Nm is the international standard unit.
LOL :). Well, okay....regular to me. My mind just doesn't work in metric! It's the only numbers I've ever known that make sense to me. I was trying to convert the 3700Nm torque figure and was like, "wait, what, that's not right"....
 

3V Pilot

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#10
Foot-pound is not regular anywhere, including the US ;) .
Yes but lb-ft just doesn't roll off the tongue as easy.....For some reason every time I see that abbreviation my dyslexia kicks in and my mind calls it foot-pound, it just sounds nicer. May not be correct but hey, I'm the only one living in the little world inside my head!!...:D
 

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#11
It's all too easy to get wrapped up in the high torque figures, but on their own, they are pretty meaningless.

At the end of the day, it's power that actually dictated the performance, ie, how fast you can accelerate, etc etc.

Without knowing the RPM said torque is available at, quoting XYZ is pointless.

Now, elec motors have (usually!) flat torque output from ~0-X RPM, at which point, the torque drops off with speed, so in real terms, the higher RPM X is, the better.

Tesla will get their motor(s) as a compromise between good acceleration (high ratio) and good top speed (low ratio) based on the point where the torque starts to drop off and the max RPM the motor can do (ICE engined cars are no different, you typically have less RPM range to play with and a multi-speed gearbox).

There are plenty of cars out there that have higher torque at the wheels than the Tesla, but only in low gears, the reason the Tesla can beat them off the line is more to do with the level of control they have with the electric motor, being able to be at or around the peak traction limit of the tyres, this is for all intensive purposes, much harder when you're dealing with an ICE because the control of said engine is limited by the firing rate, engine inertia, etc etc etc. that said, some do a very impressive job (Porsche 911 turbo for example).
 
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ölbrenner

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#12
The MT link I pointed out gives meaning (i.e. measured performance). It's gonna be a fun ride (as Mike Land confirmed in another thread).
 

Scuffers

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#13
If the figures in the manual are correct:

3,700Nm / 9 = 411.11Nm = 303.22Lbft

165KW = 221.27Bhp (224.34ps)

so, based on that, torque drops of a 3,832 Rpm motor speed which seems very low considering max motor speed is 17,900Rpm?

if that's correct, then torque at 17,900 would be 64.9Lbft as not to exceed the 165KW max power

I'm assuming from this that the max power is artificially limited - no great surprises there, they seem desperate for this 3 not to encroach on the S performance figures, this would also play out if they are actually using the same base motor components in the truck where a lot more power is required.
 

3V Pilot

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#14
I absolutely agree that this car is going to be fun to drive and to own. Funny thing is I'm really not one of those who is obsessed by the numbers. Horsepower and torque (no matter how you like to measure it:D) can never define the pure feeling and driving pleasure that some cars give. It's not all about numbers but I was just curious to compare this to some other cars out there and I guess sometimes the numbers are one way to do that. I'll try to avoid making any more references to Foot-Pounds, even though I like it better:p, and I'll just stick to the Nano-Meter, because hey, Mork from Ork was was cooler than Sir Isaac!!...LOL;) (yes, that is just a joke, I know it's wrong also)
 

3V Pilot

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#15
If the figures in the manual are correct:

3,700Nm / 9 = 411.11Nm = 303.22Lbft

165KW = 221.27Bhp (224.34ps)

so, based on that, torque drops of a 3,832 Rpm motor speed which seems very low considering max motor speed is 17,900Rpm?

if that's correct, then torque at 17,900 would be 64.9Lbft as not to exceed the 165KW max power

I'm assuming from this that the max power is artificially limited - no great surprises there, they seem desperate for this 3 not to encroach on the S performance figures, this would also play out if they are actually using the same base motor components in the truck where a lot more power is required.
I was actually wondering if Tesla had some software limit or de-tuned this thing to hold it back a bit. Could it be the same motor in the new Roadster?
 
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4701

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#16
I was actually wondering if Tesla had some software limit or de-tuned this thing to hold it back a bit. Could it be the same motor in the new Roadster?
We can be pretty sure in that.
Tesla isn't making new motor designs just for fun. RWD M3 has one, Roadster2 has three, Semi has four motors of same kind.
What is different is reduction gear ratio, inverter capacity and cooling capacity.
Changing motor internal design is complicated, expensive and unnecessary.
Changing inverter current capability is simple. Though I don't think it's actually necessary for all these vehicles,
except if it helps cuttings costs (applies to M3 only).

Model 3 definitely has somewhat limited power. Pretty much same story like before with Model S.
That also depends on voltage drop. Model 3 battery will have much bigger drop compared to semi at full load.

4x165kW will not move 36 tons from 0-100 in 20 seconds. Needs to be around 20% more per motor.


PS: multiply M3 torque by 3 and check Roadster2 torque.
 
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4701

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#18
Just noticed that acceleration up to 50mph is near constant.
0-30 2.1 sec
0-40 2.9
0-50 3.7
0-60 4.8
0-70 6.1
0-80 7.7
0-90 9.6
0-100 12.0

0,7sec every 10mph from 0-30mph (average)
0,8sec from 30-40,
0,8sec from 40-50.
Then it gets worse,
1,1sec from 50-60
1,3sec from 60-70
1,6sec from 70-80, some of that is drag of course.
1,9sec from 80-90
2,4sec from 90-100.

50mph translates to around a third of rpm range with near identical acceleration (aka maximum output power?).
Don't know the mass of the vehicle to estimate power required for these results (1800kg?)
So we can assume torque starts to taper at 33mph and power somewhere between 50-55mph?

So should it look something like that?
 
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Insaneoctane

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#19
I am not sure the decreasing acceleration isn't just a function of increasing aerodynamic drag. Power available to accelerate the vehicle decreases with velocity in a non-linear, polynomialistic fashion. That's right, I just made that term up! I am also curious when the motor torque starts to fall off, I just don't know if we can conclude it yet...
 

Scuffers

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#20
I am not sure the decreasing acceleration isn't just a function of increasing aerodynamic drag. Power available to accelerate the vehicle decreases with velocity in a non-linear, polynomialistic fashion. That's right, I just made that term up! I am also curious when the motor torque starts to fall off, I just don't know if we can conclude it yet...
Yes and no.

This is where the link between torque and power get confusing.

that graph is somewhat misleading because it's mixing units, if you re-label the bottom axes with motor RPM, then you would have a classic power/torque graph, although it should look more like this:


Not the lack of 'step' on the falling torque curve after base speed.

(this graph is a typical perm mag motor without any software torque shaping)

Now, back to first principles, torque is a factor of voltage applied to the motor, the higher the voltage, the more torque.

as you go up the rev range, the current (amps) to the inverter needs to rise as the frequency rises - voltage to the motor remains the same.

Once you get to the current limit of the inverter (or motor) then you are at the point in the graph labeled "base speed".

After this, assuming you maintain the current level, the voltage to the motor will start to drop and thus the motors torque, the power curve will basically go flat at this point as you have reached the maximum power for the system (in reality, at higher revs, the power will drop off marginally as the changes in motor/inverter efficiency take effect, but assuming a well designed system, this is not that significant).

Back to the 3, from what we have seen (if the numbers are to be believed), the base speed for the 3 is either ~3,832Rpm (Max power 165KW or ~4,700Rpm (202KW) - all assuming the torque figure given (3,700Nm / 9 = 411.11Nm = 303.22Lbft) are correct.

Then we get to acceleration - F=MA
combined with aero drag -

and finally, rolling resistance - Fr = c W

The first we can work with, the second & third requires the Aero/coefficient of rolling friction figures for the 3 (anybody got figures for the 3?)