Question about power capacity of electrical motors.

RT ran a story a few days ago on dead cat sex in LA, the guy got 15 years. ANd he was not famous or a genuis.

It's been used instead of copper before....

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You are correct that the resistance and heat conduction are very important as well. However, these factors are all closely related. For instance to test the current carrying capacity, increasingly larger currents are sent through the wire until it melts. But this measurement is dependent on surrounding conditions. You would get a higher measurement by blowing cooling air or other coolant over the wire, which also has relevance for their use in high power motors as they always have some cooling system involved.

But in any case, in regards to the copper-nanotube composites, the question may be moot. NASA tried to reproduce the claimed high current capacity and was unable to:

Highly Conductive Wire: Cu Carbon Nanotube Composite Ampacity and Metallic CNT Buckypaper Conductivity. Author and Affiliation: de Groh, Henry C. (NASA Glenn Research Center, Cleveland, OH United States) Publication Date: Apr 17, 2017 Document ID: 20170003881 (Acquired May 12, 2017) Subject Category: ENGINEERING (GENERAL); METALS AND METALLIC MATERIALS; AIRCRAFT PROPULSION AND POWER Report/Patent Number: NASA/TM-2017-219480, E-19350, GRC-E-DAA-TN39659 Document Type: Technical Report [quote]Results Ampacity The average ampacity of the wire specimens tested is presented in Figure 3. The variation of the Cu ampacity measurements was ?1.6 percent, for TerraCu ?2 percent, and ?10 percent for the yarn. Contrary to other accounts (Ref. 23) and claims (Ref. 24) the CNT present in the TerraCu did not improve the material?s ampacity. Likely reasons for the low ampacity in the TerraCu include the presence of s-CNT and the low volume fraction CNT employed in the composite. Ampacity is not a material property. It is a measurement that can be influenced by experimental factors such as levels of cooling. When a long wire is placed in service and is getting warm due to current flow it must shed that heat out radially- not longitudinally. In the ampacity testing of very expensive CNT composite wire it is common practice to use a rather short section of wire, connected at its ends to very heavy connectors; it is also common to imbed the wire in a large chunk of metal such as Pb-Sn solder. These heavy end connections, and complete encasement enable longitudinal heat flow which corrupts the ampacity measurement. Here is why: It is common for CNT composites to have a texture where in the CNT are primarily arranged longitudinally as a result of the wire drawing process. The thermal conductivity of CNT is not isotropic; the longitudinal thermal conductivity of CNT is very high, but the radial thermal conductivity of CNT is extremely low. Ampacity tests that enable or enhance longitudinal heat flow create an advantage for CNT wire that is not usually present in practical applications. The high ampacity results of others may be in part due to the ability of CNT to longitudinally conduct heat. Very good electrical connections were made in the tests presented here, however, these connections were tangential, thus enabled much less surface area for the conduction of heat.[/quote]

The extreme, high current capacity and extremely high thermal conductivity has been well documented for carbon nanotubes themselves, however. But they still are only available at up to centimeter lengths. Then the problem remains how to combine them into longer lengths.

Some proposals here:

From Nanoscale to Macroscale: Applications of Nanotechnology to Production of Bulk Ultra-Strong Materials. American Journal of Nanomaterials. Vol. 4, No. 2, 2016, pp 39-43. doi: 10.12691/ajn-4-2-2 | Research Article.

Bob Clark

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21st-century technology, from the space elevator, to private, orbital launchers, to 'flying cars'. This crowdfunding campaign is to prove it:

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So you are saying the only aircraft that can be powered by solar cells are the ones that can be powered by solar cells?

What point are you trying to make?

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Rick C

John Larkin wrote on 7/15/2017 3:51 PM:

Of course, you only need to accelerate for short periods, like a few seconds. After that you are running illegal speeds anywhere in the US. Why design it to run full power beyond all use cases? Your Audi will melt down if you hold the pedal to the metal all day long too.

That's a pointless number. The car runs 300+ miles on a charge and recharges while you have a cup of coffee. Who cares about pointless numbers? You just like to whine.

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Rick C

Thanks for that info that even with high current you run into the problem of magnetic saturation, where the magnetic field produced levels off:

Saturation(magnetic).

According to this wiki article the best you can get is with iron alloys at

2.2 T (Tesla).

However, I've heard of cases of high intensity magnetic fields where you can get continuous, sustained fields significantly higher than this:

Orders of magnitude (magnetic field).

11.7 T 117 kG Field strength of a 500 MHz NMR spectrometer 16 T 160 kG Strength used to levitate a frog[14] 23.5 T 235 kG Field strength of a 1 GHz NMR spectrometer[15] 36.2 T 362 kG Strongest continuous magnetic field produced by non-superconductive resistive magnet.[16] 45 T 450 kG Strongest continuous magnetic field yet produced in a laboratory (Florida State University's National High Magnetic Field Laboratory in Tallahassee, USA).[17]

I imagine then these are using superconductors?

Bob Clark

Not correct. It completed the lap, but when the engine and batteries heated up to their limits the power output was reduced. Still, it managed to complete the 14 mile lap in 10 minutes. Not bad for a two and a half ton luxury sedan.

What's amazing in the video is how quiet the car is. You hear every other car on the track, but the Tesla makes very little noise. I wonder if he used auto-pilot?

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Rick C

Why do you feel electric motors can't be improved with new materials?

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Rick C

Den fredag den 21. juli 2017 kl. 12.22.20 UTC+2 skrev rickman:

Not exactly impressive, Sabine Schmitz did 10:08 in a 136hp diesel Ford transit van

he was trying to set a fast lap not go to the shop for some milk

Den fredag den 21. juli 2017 kl. 12.00.20 UTC+2 skrev rickman:

few cars have a cooling system that can handle racetrack full power stop-and-go, but I'd think an Audi can handle full power autobahn driving for extended periods

Towing a boat up a mountain takes a lot longer than a few seconds. Gas engines do that just fine.

Power to weight ratio is important if you care about acceleration.

Cheers

Phil Hobbs

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If you would read the post for understanding, you would know that I am saying only sailplanes have enough surface area to collect enough energy to keep themselves in the air.

For the vast majority of airplanes the available surface area is too small to provide the energy the airplace requires to remain airborne.

You do know that the amount of solar energy available is limited by the solar irradiance, which is apporximately 1 kM/m^2 at noon on a clear day, don't you?

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Jim Pennino

You still don't understand any of the real issues.

Electric motors heat fail well before the windings melt.

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Jim Pennino

No, not if you're going up-hill. (Gasoline engines are of course much more suitable in that case.)

No, not unless you block the airflow through the radiator.

Why did anyone bring it up, then?

But what if you don't want to have coffee but just want to proceed without waiting one hour?

If they are truly pointless nobody cares. If anyone does care, I think you shouldn't be so sure that they are pointless numbers.. (But then again, people care about astrological predictions as well.)

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Jos

The current state of the art for electric motors is over 95% efficiency, which does not leave a lot of room for any improvements of any kind.

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Jim Pennino

Since the mid '60's cars sold in Arizona have had oversized radiators.

over-heat. At 110MPH, I run cool ;-) ...Jim Thompson

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very true.

the Nazi's invented "Magnetic amplifiers" for use in the V2, (before transisters)

the MagAmps use AC bias, and were optomized for analog computers in the USA 1950's and 1960's for aircraft.

these magamp computers were neclear hardened, because of the use of magnetic amplifiers can deal with EMP.

the Magamp is also 99% effecient. there are some switching power supplies based upon magamps, and they are 99% effecient.

I know that a sailplane is a glider which the solar powered planes are *not*.

I know that you haven't made a point about the solar powered plane. It is constructed like a glider, so what? Have you seen pictures of the Wright brothers plane?

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Rick C

There are powered sailplanes, also known as motor gliders.

You still don't get it do you, or are you being dense on purpose just to argue?

There is some minimum amount of power required to keep an airplane flying.

Powered sailplanes require very little power to keep flying and have wings with a very large surface area, therefore it is practical to have a solar powered sailplane.

A common airplane such as a Cessna 172 does not have enough wing area to collect enough energy to fly, therefore it is not practical to have a solar powered Cessna 172.

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Jim Pennino