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Comment by 7e | Hacker News Reader

Are we sure this is actually an upgrade?

This is what they said 12 years back. https://www.tesla.com/blog/induction-versus-dc-brushless-mot...

the corporate-speak blurb calls that into question, too.

"the permanent magnet machine better solved our cost minimization function.."

Hard to know whether or not to interpret that as "This is cheaper, and thus increases our profit, allowing for further production." or "This is more efficient, appealing to a broader market with larger range numbers and ensuring profit."

> So, as you know, our Model 3 has a permanent magnet machine now. This is because for the specification of the performance and efficiency, the permanent magnet machine better solved our cost minimization function, and it was optimal for the range and performance target.

> Quantitatively, the difference is what drives the future of the machine, and it’s a tradeoff between motor cost, range and battery cost that is determining which technology will be used in the future.”

Seems like those new motors are cheaper to produce and more efficient, however, they suffer from a negative effect called "torque ripple" that a lot of people notice on single motor model 3s under full throttle.

Here's a video that among other things attempts to explain this: https://www.youtube.com/watch?v=XzspO4-T7t4

I'm not in the market for Teslas atm, but after watching this, I think I'd prefer the old smoother motor over the new one.

Front motors will remain induction, as is in the AWD and Performance Model 3's. Only the rear motor will change.

Torque Ripple is only an issue on the single motor Model 3s.

The Model 3 is more efficient than the S and X, so yes it is an upgrade at least in range for a given battery.

Yes, it was already pretty well understood that the new M3 motor design was superior to the S/X so it's not too surprising that they'd upgrade the entire lineup to the new shiny. Especially if you consider the S/X are supposed to be at the top of the lineup.

don't permanent magnets lose their strength over time ?

No. Unless you heat them very hot.

They'll have software to stop them getting too hot, so the magnetism will effectively last forever

How can software lower tempurature? Limiting maximum usage, like clocking down a cpu? If so, to keep the magnets from going bad, they have to slow the car down at times. That sounds bad. I Dont mind if my cpu loses 500Mhz, but my car not accelerating could be a safety problem

Gas engines also have over temperature problems. Indeed, there is an entire cooling system do deal with it. Mostly, as long as that is working and you aren’t going full throttle on an extremely warm day you don’t have to think about it.

Any mechanical assembly will have a maximum working temperature, it’s just a matter of figuring out witch critical component will fail first and planning accordingly.

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