The Electric Motor Design Question

The Electric Motor Design Question

I also posted this in another forum not this one in case someone signed up for both forums.

I just signed up today hello everyone!! I currently own a 2015 Honda Accord Hybrid touring and get about 50-53 mpg. I am signing up to get a Tesla Model 3 and had a couple quick questions that neither tech support nor the service centers can answer. Maybe only an Engineer can answer this one?

I saw a 19 minute video on the building of a tesla model S and they showed enough coverage on the motor design where I can see the copper winding's used are rounded. The 2017(they skipped 2016) Honda Accord Hybrid and 2016 Toyota Prius 4 went with a different design this year and not sure why? They chose to go with flat (tape like) or square like copper winding's. Is it possible the Model 3 will have this newer design?

There are several advantages to tape like versus round. The only disadvantage would be the greater precision needed to wind them so they do not fall off on top of each other and the vertical winding is a bit trickier. In the end they can design a smaller motor with more torque that runs cooler.

Would anyone know about this new process and care to comment on how Tesla may move forward on this newer design?

Link about the round versus square copper wire below.


milesbb | 22 juli 2016

Tesla's electric motor gets very high hp per lb by operating at very high rpm and corresponding high frequency voltage input. This high rpm comes with a bit of efficiency penalty, but gains with significant weight and volume savings. Volume is reduced when going to a tape or a square conductor by reducing the air gap between the conductors. I believe building a motor using tape complicates the motor construction process. I also believe skin effect will be much more significant with a tape conductor as apposed to a round conductor. Skin effect will reduce the advantage of a tape design and this penalty goes up with frequency. Over my career I have seen lots of industrial motors of all sizes, I do not recall seeing tape used in any motor smaller then 1,000 lb.

I suspect Tesla is very happy with the current design of their motor so you will find a very similar unit in the Model 3. If Tesla does go to a significant motor design change I suspect they will go to a permanent magnet synchronous motor as other EV are using, again with round conductor stator windings.

brando | 25 juli 2016

Always a good review to help understand electric motor choices.

blue adept | 31 juli 2016

What is hysteresis?

johnse | 31 juli 2016

Skin effect concentrates current towards the surface of conductors, becoming more pronounced at higher frequencies. Thus, the conductivity becomes more proportional to the circumference than the cross-sectional area of the conductor. From some quick reading, it seems vertically stacked rectangular wire may be most efficient in this regard.

This is complicated by proximity effect. Good articles on both can be found on Wikipedia.