Question about power capacity of electrical motors.

Started by Robert Clark July 15, 2017
I read that the Tesla electric motor is able to achieve its remarkable power 
to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline 
engine, because it tightly winds its copper wires in its coils therefore 
being able to carry more current in the same space. If so, then we should be 
able to produce more power if we have a material that can carry more 
current.

Carbon nanotubes are such a material. In tests they can carry orders of 
magnitude more current than ordinary conductors such as copper, aluminum, or 
gold. The problem is they've only be able to be produced for short lengths, 
a few centimeters at most.

But an interesting research on nanotube-copper composites showed they can 
carry a 100 times more current than standard copper. So for the same size 
electric motor we could produce 100 times more power than currently:

Posted: Aug 06, 2013
Novel CNT-copper nanocomposite delivers a 100-fold increase in current 
density
http://www.nanowerk.com/spotlight/spotid=31710.php

For the Tesla that would not be as major a deal because of the small size of 
the motor at only about 32 kilos for the Tesla S, a vehicle that weighs 
thousands of kilos.

But that would be major for large scale motors used in other scenarios. 
These can weigh thousands of kilos, and could then be reduced to only tens 
of kilos. It would also be especially important for proposed electric 
aircraft that many groups are working towards.

So is it really true we can increase electric motor power levels simply by 
using wire of higher current capacity?


Bob Clark

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Finally, nanotechnology can now fulfill its potential to revolutionize 
21st-century technology, from the space elevator, to private, orbital 
launchers, to 'flying cars'.
This crowdfunding campaign is to prove it:

Nanotech: from air to space.
https://www.indiegogo.com/projects/nanotech-from-air-to-space/x/13319568/
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In sci.physics.electromag Robert Clark <rgregoryclark@gmspambloackail.com> wrote:
> I read that the Tesla electric motor is able to achieve its remarkable power > to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline > engine, because it tightly winds its copper wires in its coils therefore > being able to carry more current in the same space. If so, then we should be > able to produce more power if we have a material that can carry more > current.
We have such a material and it is called silver.
> Carbon nanotubes are such a material. In tests they can carry orders of > magnitude more current than ordinary conductors such as copper, aluminum, or > gold. The problem is they've only be able to be produced for short lengths, > a few centimeters at most. > > But an interesting research on nanotube-copper composites showed they can > carry a 100 times more current than standard copper. So for the same size > electric motor we could produce 100 times more power than currently: > > Posted: Aug 06, 2013 > Novel CNT-copper nanocomposite delivers a 100-fold increase in current > density > http://www.nanowerk.com/spotlight/spotid=31710.php
Current density and power are two different things. The actual issue is temperature rise because of winding resistance.
> For the Tesla that would not be as major a deal because of the small size of > the motor at only about 32 kilos for the Tesla S, a vehicle that weighs > thousands of kilos. > > But that would be major for large scale motors used in other scenarios. > These can weigh thousands of kilos, and could then be reduced to only tens > of kilos. It would also be especially important for proposed electric > aircraft that many groups are working towards.
The problem with electric airplanes is the lack of a power source that is comparable to gasoline or jet fuel not the weight of electric motors.
> So is it really true we can increase electric motor power levels simply by > using wire of higher current capacity?
No, you need to reduce resistive losses and/or get rid of heat. -- Jim Pennino
On Sat, 15 Jul 2017 13:43:55 -0400, Robert Clark

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Got a super-battery to go with your super-motor, though?
On 15/07/2017 19:31, jimp@specsol.spam.sux.com wrote:
> > The problem with electric airplanes is the lack of a power source that is > comparable to gasoline or jet fuel not the weight of electric motors. >
Solar cells work so long as you stay above the cloud and keep to the lit hemisphere! piglet --- This email has been checked for viruses by AVG. http://www.avg.com
In sci.physics.electromag Piglet <erichpwagner@hotmail.com> wrote:
> On 15/07/2017 19:31, jimp@specsol.spam.sux.com wrote: >> >> The problem with electric airplanes is the lack of a power source that is >> comparable to gasoline or jet fuel not the weight of electric motors. >> > > Solar cells work so long as you stay above the cloud and keep to the lit > hemisphere! > > piglet
Only for powered sailplanes otherwise the area available to collect energy is too small to meet power requirements. -- Jim Pennino
On Sat, 15 Jul 2017 13:43:55 -0400, "Robert Clark"
<rgregoryclark@gmSPAMBLOACKail.com> wrote:

>I read that the Tesla electric motor is able to achieve its remarkable power >to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline >engine, because it tightly winds its copper wires in its coils therefore >being able to carry more current in the same space. If so, then we should be >able to produce more power if we have a material that can carry more >current.
Teslas accelerate in short manic bursts. The motor would fry if it ran steady-state at full power. And the power/weight ratio drops a lot if you include the batteries.
> >Carbon nanotubes are such a material. In tests they can carry orders of >magnitude more current than ordinary conductors such as copper, aluminum, or >gold. The problem is they've only be able to be produced for short lengths, >a few centimeters at most. > >But an interesting research on nanotube-copper composites showed they can >carry a 100 times more current than standard copper. So for the same size >electric motor we could produce 100 times more power than currently: > >Posted: Aug 06, 2013 >Novel CNT-copper nanocomposite delivers a 100-fold increase in current >density >http://www.nanowerk.com/spotlight/spotid=31710.php > >For the Tesla that would not be as major a deal because of the small size of >the motor at only about 32 kilos for the Tesla S, a vehicle that weighs >thousands of kilos. > >But that would be major for large scale motors used in other scenarios. >These can weigh thousands of kilos, and could then be reduced to only tens >of kilos. It would also be especially important for proposed electric >aircraft that many groups are working towards. > >So is it really true we can increase electric motor power levels simply by >using wire of higher current capacity? > > >Bob Clark > >---------------------------------------------------------------------------------------------------------------------------------- >Finally, nanotechnology can now fulfill its potential to revolutionize >21st-century technology, from the space elevator, to private, orbital >launchers, to 'flying cars'. >This crowdfunding campaign is to prove it: > >Nanotech: from air to space. >https://www.indiegogo.com/projects/nanotech-from-air-to-space/x/13319568/ >----------------------------------------------------------------------------------------------------------------------------------
-- John Larkin Highland Technology, Inc lunatic fringe electronics
On Saturday, July 15, 2017 at 12:51:40 PM UTC-7, John Larkin wrote:
> On Sat, 15 Jul 2017 13:43:55 -0400, "Robert Clark"
..
> Teslas accelerate in short manic bursts. The motor would fry if it ran > steady-state at full power.
Very true - the Tesla Model S could not complete the Nurburgring course at one time because the motor overheated. The motor is liquid cooled - even the rotor has oil passing through the center. I don't know about the Tesla but the motors in other EVs are designed with a peak to average load factor of 3 or 4 to 1.
> And the power/weight ratio drops a lot if you include the batteries.
... Not only that but increasing the copper usage efficiency doesn't reduce the weight of the magnetic material which is at least 50% of the weight. kevin
On Sat, 15 Jul 2017 18:31:37 -0000, jimp@specsol.spam.sux.com wrote:

>In sci.physics.electromag Robert Clark <rgregoryclark@gmspambloackail.com> wrote: >> I read that the Tesla electric motor is able to achieve its remarkable power >> to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline >> engine, because it tightly winds its copper wires in its coils therefore >> being able to carry more current in the same space. If so, then we should be >> able to produce more power if we have a material that can carry more >> current. > >We have such a material and it is called silver.
That would make the chop shops happy.
>> Carbon nanotubes are such a material. In tests they can carry orders of >> magnitude more current than ordinary conductors such as copper, aluminum, or >> gold. The problem is they've only be able to be produced for short lengths, >> a few centimeters at most. >> >> But an interesting research on nanotube-copper composites showed they can >> carry a 100 times more current than standard copper. So for the same size >> electric motor we could produce 100 times more power than currently: >> >> Posted: Aug 06, 2013 >> Novel CNT-copper nanocomposite delivers a 100-fold increase in current >> density >> http://www.nanowerk.com/spotlight/spotid=31710.php > >Current density and power are two different things. > >The actual issue is temperature rise because of winding resistance. > >> For the Tesla that would not be as major a deal because of the small size of >> the motor at only about 32 kilos for the Tesla S, a vehicle that weighs >> thousands of kilos. >> >> But that would be major for large scale motors used in other scenarios. >> These can weigh thousands of kilos, and could then be reduced to only tens >> of kilos. It would also be especially important for proposed electric >> aircraft that many groups are working towards. > >The problem with electric airplanes is the lack of a power source that is >comparable to gasoline or jet fuel not the weight of electric motors.
Props are rather old-school, too.
>> So is it really true we can increase electric motor power levels simply by >> using wire of higher current capacity? > >No, you need to reduce resistive losses and/or get rid of heat.
And.
On Saturday, July 15, 2017 at 12:09:24 PM UTC-7, piglet wrote:
> On 15/07/2017 19:31, jimp@specsol.spam.sux.com wrote:
> > The problem with electric airplanes is the lack of a power source that is > > comparable to gasoline or jet fuel not the weight of electric motors.
> Solar cells work so long as you stay above the cloud and keep to the lit > hemisphere!
The albatross is a proof-of-concept that covers fish-powered flight. There's enough energy storage for overnights, too. So one needs SOMETHING for energy, but it doesn't have to replace hydrocarbons, it only has to replace fish.
You can build one with superconductors, but you have to be careful of three 
things:
1. Type 2 superconductors have AC losses.  Preferably, this would be done 
with type 1, at LHe temperatures.
2. You can't use magnetic materials very well.  Well, you could -- but you'd 
only be gaining a paltry ~tesla before saturation, when you have several 
tesla available with the superconductor.  They'd also be lossy, putting out 
heat that you don't need.
3. The cryocooler is going to set you back more, in space and power, than 
doing it with copper in the first place, not to mention the expense (and 
making slip rings, and low resistance connections, and..).

Although one neat thing is, you can avoid slip rings by using a 
superconducting loop for the rotor (thus you get a superconducting BLDC 
machine).  Much stronger than NdFeB, and as long as the cryocooler never 
shuts down, it never demagnetizes.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com

"Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> wrote in message 
news:okdk1a$426$1@dont-email.me...
>I read that the Tesla electric motor is able to achieve its remarkable >power to weight ratio of 8.5 kW/kg, about 10 times better than a typical >gasoline engine, because it tightly winds its copper wires in its coils >therefore being able to carry more current in the same space. If so, then >we should be able to produce more power if we have a material that can >carry more current. > > Carbon nanotubes are such a material. In tests they can carry orders of > magnitude more current than ordinary conductors such as copper, aluminum, > or gold. The problem is they've only be able to be produced for short > lengths, a few centimeters at most. > > But an interesting research on nanotube-copper composites showed they can > carry a 100 times more current than standard copper. So for the same size > electric motor we could produce 100 times more power than currently: > > Posted: Aug 06, 2013 > Novel CNT-copper nanocomposite delivers a 100-fold increase in current > density > http://www.nanowerk.com/spotlight/spotid=31710.php > > For the Tesla that would not be as major a deal because of the small size > of the motor at only about 32 kilos for the Tesla S, a vehicle that weighs > thousands of kilos. > > But that would be major for large scale motors used in other scenarios. > These can weigh thousands of kilos, and could then be reduced to only tens > of kilos. It would also be especially important for proposed electric > aircraft that many groups are working towards. > > So is it really true we can increase electric motor power levels simply by > using wire of higher current capacity? > > > Bob Clark > >
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> Finally, nanotechnology can now fulfill its potential to revolutionize > 21st-century technology, from the space elevator, to private, orbital > launchers, to 'flying cars'. > This crowdfunding campaign is to prove it: > > Nanotech: from air to space. > https://www.indiegogo.com/projects/nanotech-from-air-to-space/x/13319568/ >
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