PMAC vs induction motor for model 3

[JeffK]

If you want to talk about Africa you should be talking about Cobalt.

 

[McRat]

If you want to talk about Africa you should be talking about Cobalt.

There is certainly something going on. I think China is investing quite a bit in misinformation.

The rare earth metals are apparently actually coming from the ground in the Congo. But China is hiding the source as much as possible.

 

[McRat]

What is weird, is I sign about 3-4 agreements a month to not allow African rare earth metals and cobalt into my purchases.
I don't buy metals. These are generic federal forms for anyone who works with the feds.

I also sign docs that say I don't import or export weapons constantly. If I didn't have a relationship with the State Dept, I'd have to pay thousands a year just to say I don't buy or sell guns. Go figure.

 

[TEG]

And when Tesla reported HP according to the applicable (and the only) international standard, people got upset because it did not mean the same thing that it meant for the internal combustion engine.

Incidentally, the HP ratings reported by Tesla still could be seen in the Owners Manual, and they are **not** average, but "Maximum Net Power" which according to the ECE R85 standard is maximum power that the **motor** can sustain for a period of 30 minutes.

View attachment 242346

193kW = 258hp...
Could the S & X front motor be more similar to the motor used on 3 than we thought?

 

[Saghost]

193kW = 258hp...
Could the S & X front motor be more similar to the motor used on 3 than we thought?

To the informed observer with no access to Tesla inside information, that would have seemed a very obvious approach - a mature design already in mass production, seemingly with the exact traits they needed.

We've heard repeatedly that the 3 motor is all new, whether it turns out to be Induction or PMAC, so it seems Tesla did not choose to take that approach for some reason.

 

[R.S]

Yes, I know that. I'm not saying EPA highway is a good representation, but it's a better one than the city cycle. What is better is some steady state readings at 70-80mph speeds, for example Bolt goes about 190 miles at 75mph. Would be curious how Model 3 does.

Would be very helpful if Tesla does a similar blog as below:
Model S Efficiency and Range

But since no other company really publishes something like that, potential customers can't really compare two different EVs.

 

[R.S]

Automakers report ICE power as peak HP and peak TQ. EV makers are basically reporting average horsepower because the curve is "flat".

A car accelerates over a time interval based on the average HP, or "area under the curve". Here's what a common ICE engine power curve looks like:

View attachment 242308

Note that if operational rpm range is 4000-6500 rpm during max acceleration, your average is roughly 100kW but rated peak is 110kW.

Now an electric PMAC car:

View attachment 242309

Notice how during the operational acceleration RPM the HP is constant.
If there is a gear change in the ICE during the acceleration, there is a brief negative HP output that also comes into play.

An EV at a given power to weight ratio will normally out accelerate an ICE with the same power to weight.

Here's a classic example of EV power vs ICE power in cars with similar performance:

Volts run in pure EV mode during 0-60 mph testing. They are rated at 149 HP (cough) and weighs 3523lb, assume 150lb driver, 3673lb or 24.7 lb/hp. C&D says 7.5 seconds, 0-60 mph.

The Toyota 86 Automatic (Subaru BRZ) is pure ICE with a 200 HP rating. With driver it weighs 2961lb, so it has a 14.8 lb/hp ratio.

So the 200HP, (and 560lb lighter) Toyota creams it, right? Nope. 7.7s 0-60 mph due to the ICE HP curve and automatic shifting time.

Must be traction. Once moving, the ICE Toyota will kill it, right? Nope, both 'automatics' yield the same 5.1s 50-70 mph high speed passing time. The Toyota is quicker in the 1/4 mi by 0.1 seconds though.

This holds true for most EVs, at least up to 80 mph. They punch well outside their weight class.

So you agree, 258 hp for the Model 3 seems reasonable.

 

[R.S]

I don't know R.S.
You kinda made my point. If the 330i does 5.4 and weighs 300 pounds less, how can the M3 LR go faster with only 10 more hp to offset the extra weight.
I don't think it's possible.

No I didn't. The Model S P85 is 1000lbs heavier than a Mustang GT and has 15 hp less. Still it's 0.1 s quicker to 60.

 

[JRP3]

193kW = 258hp...
Could the S & X front motor be more similar to the motor used on 3 than we thought?

Not if the 3 motor is PMAC.

S/X front motor being run by the inverter from the rear motor

 

[kbM3]

To the informed observer with no access to Tesla inside information, that would have seemed a very obvious approach - a mature design already in mass production, seemingly with the exact traits they needed.

We've heard repeatedly that the 3 motor is all new, whether it turns out to be Induction or PMAC, so it seems Tesla did not choose to take that approach for some reason.

I saw an interview with JB where he mentioned how difficult it was to start over from scratch with the Model 3 inverters and/or motors. To re-design them from the ground up even though their existing ones were already some of the best in the world.

It really impressed me. I bought some more stock immediately after that i saw that-

 

[Cosmacelf]

I saw an interview with JB where he mentioned how difficult it was to start over from scratch with the Model 3 inverters and/or motors. To re-design them from the ground up even though their existing ones were already some of the best in the world.

It really impressed me. I bought some more stock immediately after that i saw that-

Do you remember which interview it was?

 

[kbM3]

Do you remember which interview it was?

I am sorry I do not. However, on the bright side, if you need to go through every YouTube video with JB Straubel in it, you are in for a delight -

 

[JeffK]

Do you remember which interview it was?

26:46

 

[Bill25cycle]

Not sure what to make of it, but according to the Car And Driver: "The Model 3, like the Model S, is a rear-wheel-drive car in its base form, with a rear-mounted AC induction motor"

 

[Bill25cycle]

They may just have assumed that it is an induction, but the EPA form says PM

 

[vgrinshpun]

They may just have assumed that it is an induction, but the EPA form says PM

As I posted, EPA document has other info which is most likely wrong (M3 specific energy), so it is not clear how much we should trust mention of PM AC motor.

 

[stopcrazypp]

They may just have assumed that it is an induction, but the EPA form says PM

As I posted, EPA document has other info which is most likely wrong (M3 specific energy), so it is not clear how much we should trust mention of PM AC motor.

I should remind again there have been two previous examples posted where the EPA document has been wrong about the motor type (Rimac and Prius uses PMAC motors, but they are listed as induction motors in the EPA document). So that line is unreliable.

 

[Swampgator]

Has anyone read this: http://www.springer.com/cda/content...322001-c2.pdf?SGWID=0-0-45-1564117-p179924034'

I especially look forward to KarenREI's take on it. Maybe Tesla is using a hybrid type motor after all???

 

[JRP3]

Speculation from Otmar, (inventor of the Zilla controller)

 

[bjornb]

Model 3 apparently has no battery heater but use the inverter and motor even when standing still:

For example, it got rid of the external battery pack heater and instead, it heats the pack only using heat provided by the powertrain even when the car is parked.

Battery cells need to operate at a temperate core temperature in order to keep their optimal performance, which means that they need to be cooled in warm conditions and heated in cold weather.

Waste heat from the powertrain can be used when the car is moving, but Tesla designed a thermal controller for Model 3 that can also use heat from the powertrain even when the vehicle is parked, like at a Supercharger for example, which is important since the charge rate drops if the battery pack is too cold.

Even when parked, Tesla’s software can send a request to the powertrain inverter to start powering up and pass the appropriate currents to the motor in order to produce enough heat to warm the cells – all while not producing any torque so the Model 3 doesn’t move.

Tesla apparently judged the system efficient enough to not include an external battery pack heater in the Model 3 and replaced it virtually entirely through software.

Tesla Model 3: Exclusive first look at Tesla’s new battery pack architecture

Is this possible on both PMAC and Induction motors?