See what's inside a Tesla Model S motor

[Rothgarr]

Cool video. I was not expecting all those circuit boards inside the motor itself.

This is a Model S motor, btw.

 

[Rothgarr]

OK, so I posted that before making it all the way to the end. They open up the whole thing EXCEPT for the motor. I really wanted to see magnets and coils.

 

[GWord]

There's a How It's Made episode on the Model S that shows the manufacturing process for the motor and inverter that probably gives you the view you want. YouTube has some excerpts I think.

 

[camalaio]

I find the What's Inside crew's videos a bit... forced? There was so much excitement over revealing the gear set, which isn't novel or even the motor. They missed actually showing the motor in the video!! Anyhow, personal misgivings about specific YouTube channels aside...

For a better look at Model 3 (also showing the actual motor component, not just the inverter and gear set) see here:

It also goes over two other EVs and is a pretty neat video overall.

EDIT: Specifically, it's interesting to compare the Model S drive inverter (simply huge) vs. the Model 3 (very compact).

 

[KenC]

I could not make it to the end, those guys were dopes!

 

[Wratran]

There are oil in the motor. We know that oil will wear down.

Why doesn’t Tesla recomend any kind of oil service with this motor?

 

[140.6]

Dopes for sure, they never even opened the motor itself, opened the GEAR BOX and had a cow.

Rich Rebuilds videos are vastly better.

 

[camalaio]

There are oil in the motor. We know that oil will wear down.

Why doesn’t Tesla recomend any kind of oil service with this motor?

An internal combustion engine needs to deal with contaminants (combustion products) and very high heat (we push the limits of heat tolerance to get more efficient engines). There are many additives to help deal with these nasty conditions for the oil, but eventually they're depleted or denatured and thus require replacement.

The heat load in an electric motor is less "spiky" (more consistent) but can also be fairly hot, which is why they're liquid cooled as well. However, there are no combustion products that contaminate the oil. In an electric motor with permanent magnets (Model 3 rear motor), cooling is especially important so as to not demagnetise the magnets.

I suspect they've determined the heat load over time does not denature the oil sufficiently to require replacement. On the other hand, perhaps there are other issues (gear failure, failure of the motor windings/short, inverter failure) they expect to occur before the oil fails, requiring bulk replacement of the drive unit.

For comparison, some manufacturers (and different applications aside from consumer vehicles) have sealed automatic transmissions that don't necessarily require replacement of the lubricant.

 

[Wratran]

An internal combustion engine needs to deal with contaminants (combustion products) and very high heat (we push the limits of heat tolerance to get more efficient engines). There are many additives to help deal with these nasty conditions for the oil, but eventually they're depleted or denatured and thus require replacement.

The heat load in an electric motor is less "spiky" (more consistent) but can also be fairly hot, which is why they're liquid cooled as well. However, there are no combustion products that contaminate the oil. In an electric motor with permanent magnets (Model 3 rear motor), cooling is especially important so as to not demagnetise the magnets.

I suspect they've determined the heat load over time does not denature the oil sufficiently to require replacement. On the other hand, perhaps there are other issues (gear failure, failure of the motor windings/short, inverter failure) they expect to occur before the oil fails, requiring bulk replacement of the drive unit.

For comparison, some manufacturers (and different applications aside from consumer vehicles) have sealed automatic transmissions that don't necessarily require replacement of the lubricant.

this is very educational response...learn something new

 

[ajdelange]

There are no magnets in the M3 motors.

The oil seen in the video in question is in the gear box - not the motor. Tesla does recommend replacement of that oil every 3 years.

One can find pictures of the interior of the model 3 motor on the web. It's not that exciting being that it is pretty much a garden variety three phase induction motor. The squirrel cage is so tightly integrated with the rotor stampings that the rotor appears to be one big homogenouus cylinder. The stator of a three phase motor is not that interesting unless you are trying to figure out things like winding pitch.

What would be interesting to see would be how the rotor is cooled.

 

[scaesare]

There are no magnets in the M3 motors.

Incorrect.

There are magnets embedded in the rotor.

 

[brucet999]

There are no magnets in the M3 motors./QUOTE]
One of the surprises when M3 was launched was that Tesla had abandoned the induction motors used in MS and MX in favor of a permanent magnet motor. The induction motor had been one of the biggest differences between Tesla's power train and the rest of the industry.

The change improved efficiency somewhat and, I think, reduced weight, but removed the capability of the D versions to load shift from rear motor to front (at a higher gear ratio) for improved Wh/mile efficiency at freeway speeds.

 

[camalaio]

There are no magnets in the M3 motors.

The oil seen in the video in question is in the gear box - not the motor. Tesla does recommend replacement of that oil every 3 years.

One can find pictures of the interior of the model 3 motor on the web. It's not that exciting being that it is pretty much a garden variety three phase induction motor. The squirrel cage is so tightly integrated with the rotor stampings that the rotor appears to be one big homogenouus cylinder. The stator of a three phase motor is not that interesting unless you are trying to figure out things like winding pitch.

What would be interesting to see would be how the rotor is cooled.

There are no magnets in the front induction motor, but there is in the rear motor. Less heat needs to be removed from the rotor because of this new design, which surely was one of the motivators for it. I think the new "Raven" Model S/X now shipping use these motors as well, with people seeing both improved efficiency and better endurance with respect to heat loading.

Thanks for the note on replacement every 3 years though. I'm unfamiliar with Model S maintenance, having just got a Model 3 as my first Tesla experience (where they now don't even recommend replacing coolant or lubricants). Admittedly, I'm not sure how I ended up in this thread in the Model S forum

3 years is still a decently long life compared to what folks are used to in gas vehicles, though to be fair is somewhat normal for transmissions or differentials (which makes sense).

 

[brucet999]

Thank you, @camalaio, I was mistaken about both motors being permanent magnet on M3. The front is indeed induction.

 

[ajdelange]

While you guys are correct WRT the Raven today prior to its release in the spring of 2019 both motors in the model S were induction motors. Given that the video was posted 3 years ago the motor in it is from a pre Raven S, is an induction motor, contains no magnets and has a liquid cooled rotor.