Electric Motor Winding Question

[motorfr33k]

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?

The 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.

Thanks

Square Wire - RC Groups

 

[Jeff N]

I can't explain all of the details and tradeoffs. In quickly googling around, however, I did find this recent 71-page slide set about the various electric motor construction details used in various different hybrids and plugins. It includes discussion of square vs round windings.

http://sites.ieee.org/miami/files/2014/11/Hendershot-FIU-Lecture.pdf

 

[CoastalCruiser]

motorfr33k: Welcome. Very interesting thread you're pointing to. In the time I've been following Tesla I got quite interested in how induction motors work and how Tesla Motors implemented Nikola Tesla's design. I also have a reservation in on the Model 3 so I follow any motor news on this generation... but have not heard a peep about square wire.

My research efforts produced this, but the post does NOT answer your question. ;>

JeffN: That is an amazing PDF you linked to. Never seen anything so thorough.

There is a question I've always had regarding the photo on page 39 of the cut-away motor (lower right). What are we looking at? I mean what are those cut away copper bars surrounding the rotor? The cutaway makes the bars look like they are part of the Stator, but those ain't copper wire windings. One might think then that the bars are part of the squirrel cage assembly of the rotor, but unless they cut into the rotor for the cutaway that doesn't make sense either. Anybody?

 

[int32_t]

There is a question I've always had regarding the photo on page 39 of the cut-away motor (lower right). What are we looking at? I mean what are those cut away copper bars surrounding the rotor? The cutaway makes the bars look like they are part of the Stator, but those ain't copper wire windings. One might think then that the bars are part of the squirrel cage assembly of the rotor, but unless they cut into the rotor for the cutaway that doesn't make sense either. Anybody?

If you mean the copper-coloured stripy things right next to the rotor, those are wires. I visited a Tesla store and took a photo of their cutaway motor a while back, and looking at that photo again I can see the individual wires in each of those bundles (the stripes). They're round wires in square bundles.

From that forum it sounds like square wire is more of a pain than it's worth -- and Tesla's motors are pretty powerful and small already.

 

[CoastalCruiser]

If you mean the copper-coloured stripy things right next to the rotor, those are wires. I visited a Tesla store and took a photo of their cutaway motor a while back, and looking at that photo again I can see the individual wires in each of those bundles (the stripes). They're round wires in square bundles.

Helpful. That is what "should" be at that location, but it's always looked more like copper bars than a bundle. Nice to get that clearned up.

 

[int32_t]

Yeah, the wires are relatively fine so when taken together they start to look like a bundle. Rather than describing it I'll just post the picture!