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Tiny electric motor can produce more than 1,000 horsepower

supercarblondie.com

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Re: Tiny electric motor can produce more than 1,000 horsepower

#571

Post by fainpul »

margalabargala wrote: post #276
fainpul wrote: post #149

Earlier quoted context omitted.

> 59kW/kg At this point why don't we get rid of the k prefix and write 59W/g? Edit: I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can…

It gives a sense of the functional size required. Could the motor in question be shrunk down to 1kg, producing 59kW? Probably. Could it be shrunk down to 1g? No.

But it doesn't. You can talk about micro-motors, implemented on a PCB, like [1] and get a number in the same ballpark. That's the whole point – it's a ratio, it tells you nothing about the absolute size of the motor.

[1] https://tymagnets.com/pcb-motors-and-wedge-magnets/

Re: Tiny electric motor can produce more than 1,000 horsepower

#572

Post by fainpul »

Neywiny wrote: post #351
fainpul wrote: post #149

Earlier quoted context omitted.

> 59kW/kg At this point why don't we get rid of the k prefix and write 59W/g? Edit: I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can…

Ah like the old MKBHD "screen has an aspect ratio of 18:9. Or 2:1 because I know my fractions"

Or just 2. I like my screen aspect ratios in decimal representation. The "wider" the image, the larger the number. Square would be 1.

It makes it easy to compare ratios: for example the aspect ratio of a movie (say 2.39) to my screen (2.33) and see that I can expect a good fit. My screen is a bit "more square", so there will be slivers of black borders on top and bottom.

Re: Tiny electric motor can produce more than 1,000 horsepower

#573

Post by NetMageSCW »

rounce wrote: post #202
lunias wrote: post #198

Earlier quoted context omitted.

I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience... it really does compound unlike any other change that you can make to a vehicle. IMO heavy vehicles are a scam and the antithesis of the direction we should be moving.

Absolutely and on top of that far lower pollution from tyre and brake dust, and less damaging to the road top surface.

The weight difference would make an unmeasurable difference in those things.

Re: Tiny electric motor can produce more than 1,000 horsepower

#574

Post by NetMageSCW »

mulmen wrote: post #302
UnserMannInK wrote: post #254

Earlier quoted context omitted.

And shouldn’t it be possible to make the battery smaller with a more efficient motor?

The battery could be made smaller by whatever amount is needed to carry the marginal motor weight the advertised distance.

Unfortunately incremental weight is not a big power user in BEVs so it likely would make no meaningful difference.

Re: Tiny electric motor can produce more than 1,000 horsepower

#575

Post by londons_explore »

jesse__ wrote: post #498
Aurornis wrote: post #251

Earlier quoted context omitted.

> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better. EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger. Not a significant effic…

Somebody's probably already pointed this out, but in the case of motors, making them lighter can make a big difference. For example, by making the flywheel in a clutch lighter, you reduce the amount of torque it takes to spin the flywheel. Saving 10 pounds there is not a 10/3000lb difference.. it could be a huge percentage of total power output.

To be precise, the impact of mass inside the rotor of the motor is 2 * the mass * the rotor diameter / the wheel diameter * the drivetrain gear ratio.

For a typical EV, I think that works out to a factor of around 2.

Re: Tiny electric motor can produce more than 1,000 horsepower

#576

Post by ImPostingOnHN »

catapart wrote: post #560
ImPostingOnHN wrote: post #521

Earlier quoted context omitted.

I would tend to agree with the other poster that a 10lb reduction, or even a 20lb reduction, is pretty insignificant when it comes to modern consumer cars.

Right on. Buy a car with a heavier motor, then. I took this out to the shop floor yesterday and asked the guys what they could do with 10 fewer pounds in the leafs we have around, and believe me - I'm so much less excited about being vindicated in this thread, than I am about the ideas they came up with. Mostly nonsense, but there's some interesting stuff in there that I can't wait for them to try out!

I just posted this question to an executive advisory panel consisting of leaders from some of the largest car companies, and they could not stress enough how right and vindicated the other poster was, about a 10lb reduction, or even a 20lb reduction, being pretty insignificant when it comes to modern consumer cars.

I guess it's just not worth it to pay way more for a motor just because it provides a pretty-insignificant weight reduction.

Re: Tiny electric motor can produce more than 1,000 horsepower

#577

Post by roelschroeven »

taneq wrote: post #570
roelschroeven wrote: post #566

Earlier quoted context omitted.

We only know that the large and the small motor deliver the same power. I don't see how we can conclude from that the temperature differential is also equal. In fact I would expect a smaller motor to have a larger temperature differential, because the heat is produced concentrated in a smaller volume.

Yep, you're getting it. Same power, same efficiency, same power dissipation, smaller motor, smaller dissipative area, higher temperature. The other assumption I probably should have stated is that the two motors are made of similar materials with similar temperature limits. We know the ambient temperature and we know the maximum temperature of the materials used. So for a component made of those materials, existing i…

So, ok, under a whole bunch of stated and unstated unproven assumptions, a smaller motor of the same power delivery as a larger motor is more efficient. There's no relation to reality here. I don't even know why I thought the idea in your comment that started this thread was worth pursuing.

Re: Tiny electric motor can produce more than 1,000 horsepower

#578

Post by dredmorbius »

davedx wrote: post #6

Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better. YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer. "Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller…

I'd expect more applications in either aviation or mobile / portable power devices.

As others have noted, battery remains a major factor in overall mass, and motor placement (in-wheel vs. driveshaft) is a concern in ground-transport.

In aviation, battery limits overall range, but a high-power, low-range, lower-mass vehicle could be useful for short-hop flights, manned or unmanned, especially where payload considerations are paramount.

Mobile-power applications (tools, transportable equipment) might also benefit from high power-to-weight, especially if this means that overall weight limits could be more readily met (e.g., total vehicle weight, total carried weight), or additional equipment (or battery) could be provided.

Re: Tiny electric motor can produce more than 1,000 horsepower

#579

Post by SR2Z »

jlarocco wrote: post #540
lelandbatey wrote: post #526

Earlier quoted context omitted.

An ebike weighs less than a motorcycle by at least half (for super lightweight motorcycles) or less than 1/6th the weight. So a fast ebike is about as dangerous as merely the human person +100lbs traveling at speed. Thus, less energy to transmit to a pedestrian

100 pounds of bike plus 150 pounds of person hitting a pedestrian at 30+ mph is still going to do cause serious injuries to both of them. But it's really a moot point because there are essentially zero motorocycles travelling on sidewalks, bikepaths, and trails where pedestrians are going to be concentrated, while it's a free for all for e-bikes. In general, motorcycle/pedestrian accidents are pretty rare. Statistica…

Yeah, it's not going to be as bad as a 300lb bike and 150lb person with a fuel tank in the back...

There are lots of gas powered motorcycles in the bike lanes where I live. Not legal, but nobody enforces it.

Re: Tiny electric motor can produce more than 1,000 horsepower

#580

Post by SR2Z »

ghostpepper wrote: post #435
SR2Z wrote: post #385

Earlier quoted context omitted.

They are not allowed, but still commonly owned and used. The law needs to catch up. There are clearly good reasons for people to want extremely powerful e-bikes and they should be allowed to. They can't be treated like bicycles because they're too fast but aren't nearly as dangerous as motorcycles. We need a new category for light motorcycles. The real problem, IMO, is that the law is generally not deferential enough…

> They can't be treated like bicycles because they're too fast but aren't nearly as dangerous as motorcycles. Why would an extremely powerful ebike be any less dangerous than extremely powerful gas motorcycle?

It will weigh like 3x less.
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