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A couple notes about topics mentioned in the video...

Induction motor efficiency is not as bad as suggested. Look at a motor efficiency map for a Tesla Model S and it doesn't look much different from the permanent magnet synchronous motors. My guess is that you're thinking of the inefficiency of an industrial induction motor driven at constant (line) frequency starting from zero speed or being loaded too heavily and thus slipping excessively; an EV motor (or any motor properly run by a variable-frequency drive) never runs in that condition. Even at stall, the driving frequency adjusts to produce the optimal slip speed for maximum torque.

The Wikipedia note about gearing is not clear. I suspect that it was intended to suggest a 3:1 first reduction stage ("transmission") plus a second stage ("differential" or final drive, which would need to be about 4:1 to match your 12:1 observation), but this transaxle has the axles coaxial with the motor shaft and I have not seen the internal details. Obviously 3:1 overall is not right, and 12:1 is reasonable. If it is like the Chevrolet Bolt (and apparently the 2011-vintage Focus EV), a first stage pair of parallel gears drives a parallel shaft (which appears to be above and behind the motor and axle shafts), and the second stage from that shaft to the diff carrier uses a typical (for a transverse transaxle) driving gear and driven ring gear. If anyone has opened the case on one, they can just count teeth for the ratios.
 

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Yes, the Ford Ranger Electric doesn't have a true single reduction gear; it has a " two-stage direct reduction planetary gear system." The Bolt EV's reduction gear is technically a "parallel-helical reduction gear." From the end user's perspective, though, it shouldn't change things. The Ford Ranger Electric has a fixed gear reduction of 12.518:1.
Yes, the Bolt is a helical parallel gear train. The earlier Spark EV had a planetary reduction (the only easy way to build a single reduction stage coaxially), but it has just one stage to deliver its unusually small 3.7:1 reduction ratio; when GM went to a more typical reduction ratio requiring two stages, they got rid of the planetary design.

Thanks for the Ranger info. :) It's not surprising that the Ranger has two stages, given the desired reduction ratio, but it's surprising and interesting that they went with a planetary design.
 

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The Tesla Model S is horribly inefficient. ... In head-to-head testing at 75 mph, it was more than 10% less efficient than the Bolt EV...

These induction motors in particular produce enough waste heat that they require a 16 liter per minute glycol cooling loop. Induction motors are for sure less efficient than PMAC.
Okay, but in the video you were talking about huge cooling systems suggesting much greater loss - an automotive cooling system for an engine dissipates almost as much energy as goes into the output shaft.

The overall efficiency of the Tesla Model S isn't terrible - compare the energy consumption per distance travelled to other large EVs and (even after allowing for a Musk-style bias to the numbers) it's reasonably comparable.
 

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I think the best proof of the efficiency advantage of PMAC motors is Tesla's own transition from induction to PMAC motors as a means of improving their vehicles' efficiency.
I agree with that. Tesla started with whatever was available cheaply, and has avoided significant changes to the Model S/X. With the Model 3 they switched to current technology.

Induction motors can still make sense in applications where they are spinning idle much of the time, such as in front drive units of mid-engine hybrids or AWD EVs in which the designer chooses to run only one motor normally. The Tesla Model 3 and Audi Q4 Sportback e-tron both have an induction motor in front and a PM motor in the rear; they presumably run as rear wheel drive until front drive is needed for traction or power.

In a bizarre twist, Tesla has updated the Model S/X front motor to PM, keeping the induction motor at the rear - they will presumably run as front-wheel-drive vehicles at low power.
 
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