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Electric motor design claims remarkable improvements

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Re: Electric motor design claims remarkable improvements

#121

Post by londons_explore »

adammunich wrote: post #109
dzhiurgis wrote: post #100

Earlier quoted context omitted.

While motor efficiency is 90%, drivetrain is less than that because of gearbox. This motor claims to remove this inefficiency.

A reduction gear is really not all that much of a loss, wind on the other hand-- that's a big one.

Airflow losses in big AC generators are solved by having the whole motor sealed in helium. The helium gas is used as a coolant too.

It would be hard to design such a system with a big enough supply of gas to survive leakage for the whole life of the motor though.

Re: Electric motor design claims remarkable improvements

#122

Post by londons_explore »

bob1029 wrote: post #93
sunstone wrote: post #56

Earlier quoted context omitted.

Electric motors are remarkably good already. Even if it doubled the power for half the weight you still need lug along all those batteries.

I am not sure why we are focused on the electric car angle. Assuming this motor design is legitimate and practical, I feel the implications for commercial/industrial prime movers and power generation are far more substantial. Hypothetically, if we were to replace all existing HVAC compressor and blower motors with this technology, where would that leave us in terms of power consumption reduction? How much wider do th…

HVAC systems are far from theoretical peak efficiency. For example, notice how they all have a 'capilary tube' to restrict the flow of liquid coolant between the hot and cold sides of the system? That's like using your brake to go slowly round town rather than letting off he gas...

A small turbine rather than that capillary tube would instantly increase system efficiency...

Re: Electric motor design claims remarkable improvements

#123

Post by hwillis »

mrfusion wrote: post #117
blattimwind wrote: post #51

Earlier quoted context omitted.

It's mostly Coulomb's law; electrostatic force is proportional to the involved charges divided by their separation. You don't have that problem in electromagnetic motors because strong magnetic fields don't break down the rotor/stator air gap. You might turn the air gap into a dielectric oil gap, but now you have fluid friction losses which again limit how narrow that gap can be. You'll note that this is a recurring…

Good explanation. So it makes me wonder if we could improve on the capacitor if we could find its magnetic counterpart. Does that even make sense?

like... an inductor? Inductors and capacitors are opposite in behavior, but a series capacitor can be replaced with a parallel inductor and vice versa. In that sense they are counterparts.

It is not possible to make an inductor out of purely passive capacitive components, or vice versa. In fact the Gyrator[1] is a transistor circuit that exists specifically to act like an large inductor using capacitors, which are cheaper to build at large values. The function of a Gyrator inherently requires active power input; it isn't possible to passively convert the phase lag of a magnetic circuit into the phase lead of a capacitive circuit.

[1]: https://en.wikipedia.org/wiki/Gyrator

Re: Electric motor design claims remarkable improvements

#126

Post by JetSpiegel »

corodra wrote: post #53

Don't get me wrong, I saw the title and was excited. I want this to be real. I want to believe. But way too many keyword drops. Disruptive is what red flagged me the most. Way too many promises. Only lab results and "experts" commenting that it should work in theory. But no prototype? Even though it's a different motor they don't "believe" it's going to cost more to make than traditional motors? Only 3d renders? I th…

> But no prototype?

See examples of this done right:

- https://en.wikipedia.org/wiki/Turbinia#Demonstration - Frank Zapata's "thing" on Bastille Day and the Channel crossing

Re: Electric motor design claims remarkable improvements

#127

Post by mikeash »

londons_explore wrote: post #118
mikeash wrote: post #102

Earlier quoted context omitted.

Tesla claims that their drive unit (which includes the motor, inverter, and gearbox) efficiency on their latest models is 93%.

Average or peak? Making something that performs well at freeway speeds, yet also is efficient when manuvering round a parking lot is hard. Most companies just hope you don't care about only getting 5% efficiency round the parking lot, because that isn't a large fraction of your energy budget, even when it's so inefficient.

No idea! Would it be expected for an electric motor to lose so much efficiency in that scenario, though? I though the variation was small.

Motor efficiency aside, a total “energy spent for distance moved” accounting will look bad at such low speeds, just because the car has to power non-motor systems and they use energy at the same rate no matter how fast you’re moving. Peak efficiency in a Tesla is at around 25MPH.

Re: Electric motor design claims remarkable improvements

#128

Post by mikeash »

londons_explore wrote: post #119
mikeash wrote: post #116

Earlier quoted context omitted.

The early Model S motors had problems like that. They got a lot better over the years. The Model 3's is great, and the Model S/X front motors are now the same as the Model 3's, while the rear motors are something else that's still a lot better.

Any clues what exactly within the motors fails?

There’s usually a funny noise long before any catastrophic failure, so I think it’s the bearings or the gears, but concrete information is hard to find.

I actually had my motor replaced due to this noise. It was a high pitched whining, kind of like a jet engine spooling up. Not real loud, most noticeable in a parking garage with the roof open, and I wasn’t even sure if it was abnormal, but I took it in and they replaced it. It’s easy to swap out, so they just put in a new one and then fix the old one at their convenience and give it to the next victim.

Incidentally, I had another weird noise sometime later which was a distinct clunking sound when accelerating from a stop. That turned out to be a bolt that wasn’t tightened properly. Oops!

Re: Electric motor design claims remarkable improvements

#129

Post by mikeash »

londons_explore wrote: post #121
adammunich wrote: post #109

Earlier quoted context omitted.

A reduction gear is really not all that much of a loss, wind on the other hand-- that's a big one.

Airflow losses in big AC generators are solved by having the whole motor sealed in helium. The helium gas is used as a coolant too. It would be hard to design such a system with a big enough supply of gas to survive leakage for the whole life of the motor though.

Airflow losses for a car will be dominated by the outside air. Surrounding the car with helium seems impractical, and hard on the occupants.

Re: Electric motor design claims remarkable improvements

#130

Post by corodra »

JetSpiegel wrote: post #126
corodra wrote: post #53

Don't get me wrong, I saw the title and was excited. I want this to be real. I want to believe. But way too many keyword drops. Disruptive is what red flagged me the most. Way too many promises. Only lab results and "experts" commenting that it should work in theory. But no prototype? Even though it's a different motor they don't "believe" it's going to cost more to make than traditional motors? Only 3d renders? I th…

> But no prototype? See examples of this done right: - https://en.wikipedia.org/wiki/Turbinia#Demonstration - Frank Zapata's "thing" on Bastille Day and the Channel crossing

Hmmm Are you suggesting that they might try doing a showy reveal?

Meh I'm okay with that. Maybe. But the amount of current publicity makes it feel like Theranos. That's why I have massive red flags being thrown up.

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