PMAC vs induction motor for model 3

[ecarfan]

To everyone who is obsessing over the PM vs. AC induction motor issue: why not just tweet Elon and ask him? If a lot of people ask him the same question, it will get his attention. I think he would like to have correct information publicly available, especially on a somewhat fundamental -- if a bit geeky -- issue like this one.

The vast majority of Tesla buyers could care less about this issue, it's meaningless to them. They want to know "How far will it go?", and "Where/how do I charge it?".

 

[R.S]

Yeah. Goodbye.

Oh don't be pissed, there are many others that were equally ignorant

 

[Jeff N]

The motor for the Bolt was a derivitive of the one used in the Spark EV. Guess which company designed that one?

I'm not sure why this post just came up just now.

What is your source on the Spark EV motor? My understanding is that the Bolt motor is a redesign and is not particularly based on the Spark design. The power vs torque and max rpm ratings are quite different.

In any case, GM manufactured the Spark EV motor itself.

 

[R.S]

Yes it should be possible, and someone on here claim to know that Tesla was going to use a hybrid approach in the Model 3. Though we don't know if that was in a single motor, or if they were going to put a PM at one end and a Induction at the other.

Induction an PMAC doesn't really work, because the induction motor needs slip, which is a no go with PMAC, or PMSMs, where the rotor runs at the same frequency as the electric field.

But hybrid reluctance motors work.

 

[SageBrush]

To everyone who is obsessing over the PM vs. AC induction motor issue: why not just tweet Elon and ask him? If a lot of people ask him the same question, it will get his attention. I think he would like to have correct information publicly available, especially on a somewhat fundamental -- if a bit geeky -- issue like this one.

The vast majority of Tesla buyers could care less about this issue, it's meaningless to them. They want to know "How far will it go?", and "Where/how do I charge it?".

I was just thinking that it really matters very little, but for some reason I hope it was a typo and the motor is induction. It is part of the Tesla mystique.

 

[No2DinosaurFuel]

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?

Still nit picking huh? Wrong spelling? Well look at the model S EPA doc and you can see they clearly put AC induction. If it was indeed AC induction for the model 3 they would put AC induction. As for the weird www3 site. I initially was sketical too until i remove the 3 from www3 and it will redirect you to the www3 site. This is the EPA.gov website. Elon says a lot of things. I guess you still need to learn to filter out the crap.

 

[Rashomon]

I think I'll wait until Tesla officially says the M3 has a PMAC motor to start the self-congratulations, but really the trend in the industry is in that direction, and for generally very good reasons. However, there is some chance of an error on the paperwork, so let's reserve judgement for the moment.

If the M3 does use a PMAC motor in part for efficiency reasons, it does make you wonder about updates to the S and X. One approach would be to run a M3 motor, perhaps the new front motor, in the front position on the non-P, non-Ludricious D models, and keep a big inductive motor in the back. That way they could have the efficiency of the smallish PMAC motor when advantageous and still have the big torque of the induction motor without all the induced drag of a similarly torquey PMAC motor at light loads.

 

[Saghost]

I think I'll wait until Tesla officially says the M3 has a PMAC motor to start the self-congratulations, but really the trend in the industry is in that direction, and for generally very good reasons. However, there is some chance of an error on the paperwork, so let's reserve judgement for the moment.

If the M3 does use a PMAC motor in part for efficiency reasons, it does make you wonder about updates to the S and X. One approach would be to run a M3 motor, perhaps the new front motor, in the front position on the non-P, non-Ludricious D models, and keep a big inductive motor in the back. That way they could have the efficiency of the smallish PMAC motor when advantageous and still have the big torque of the induction motor without all the induced drag of a similarly torquey PMAC motor at light loads.

If Tesla is in fact adopting a PMAC motor for efficiency in certain operating ranges, this seems like a very logical way to do it - no increase in complexity and parts count over the existing dual drive cars, and lots of opportunity to tune each motor for what it does best. Once you put the induction motor to sleep, it disappears except for the inertia.

 

[anticitizen13.7]

Intellectual curiosity aside, why should we care whether the motor is AC induction or Permanent magnet?

I trust that Tesla weighed the pros and cons of each motor type for the Model 3 application, and made the best choice given the different trade offs.

 

[SageBrush]

Except this entire thread is based on the EPA report of a PMAC in a single motor Model 3.

 

[ruby110]

The reason I care is I was hoping they used an existing motor. Less risk for buying early.

 

[Saghost]

Intellectual curiosity aside, why should we care whether the motor is AC induction or Permanent magnet?

I trust that Tesla weighed the pros and cons of each motor type for the Model 3 application, and made the best choice given the different trade offs.

Mostly because some folks spent days of their lives fighting over it when some rumors showed up months ago and one side now feels vindicated based on the EPA report.

As a typical end user, it doesn't matter one bit to the user experience. There are aspects that could at the edges for unusual use cases (PMAC is subject to cogging, induction overheats a lot faster, PMAC will generate currents if spun while "off", etc,) but either can make a great EV if designed appropriately.

The other thing some folks are worried about is whether the raw materials involved are available at the volumes needed for future mass production, and where they are sourced and how they are acquired. Some of the materials used in some permanent magnets are not easy to come by or overly abundant.

 

[Cosmacelf]

The reason I care is I was hoping they used an existing motor. Less risk for buying early.

Model 3 has a lot of new technologies, so no luck there!

 

[Saghost]

Except this entire thread is based on the EPA report of a PMAC in a single motor Model 3.

No no no. This thread is based on a user's unsupported speculation ten months ago that a PMAC based car would be more efficient.

The EPA report simply reawakened it from the dead.

 

[stopcrazypp]

Intellectual curiosity aside, why should we care whether the motor is AC induction or Permanent magnet?

I trust that Tesla weighed the pros and cons of each motor type for the Model 3 application, and made the best choice given the different trade offs.

Besides what was already mentioned by @Saghost, the number one thing is that Tesla's use of induction motors has always been a very strong counterpoint to one of the most common criticisms of EVs using rare earth minerals from China. If it is true Tesla switched to PMs, then that is no longer true.

 

[S3XY]

Does using a PMAC motor in the Model 3 make sense with respect to the same motor being used in the upcoming semi? In other words, simply, would a PMAC motor be better than an induction for use in a semi?

 

[Rashomon]

Does using a PMAC motor in the Model 3 make sense with respect to the same motor being used in the upcoming semi? In other words, simply, would a PMAC motor be better than an induction for use in a semi?

There's a good chance PMAC motor(s) are better for a semi because the ratio of peak to average power use on a semi is far , far less than on, say, a MS P100D. Since a semi goes down the highway using a significant percentage of its peak power, it's almost certainly operating on a higher efficiency area of its efficiency map.

 

[ZeApelido]

Man... [FLOG] you.

Still can't admit you're wrong eh?

 

[gregincal]

The Bolt's ability to do regen to a complete stop is supposed to be because it has a permanent magnet motor. That's an end user difference.

 

[stopcrazypp]

The Bolt's ability to do regen to a complete stop is supposed to be because it has a permanent magnet motor. That's an end user difference.

Actually I remember the discussion on this. All "regen to a stop" in EVs actually consume power at the lowest rpm. Tesla can theoretically do it if they want it to, nothing to do with the motor type.

Regen braking to stop? (similar to BMW i3)