Naked Science Forum

Non Life Sciences => Technology => Topic started by: CliffordK on 13/07/2011 08:22:38

Title: Can you make motor windings out of Carbon Fiber?
Post by: CliffordK on 13/07/2011 08:22:38

I was thinking about lightweight electric motors, and started wondering if one could make motor/generator windings out of Carbon Fiber rather than copper.  I see notes of companies that are making other electric motor components out of Carbon Fiber, but not the windings.

Perhaps embed it in a non-conductive resin and forming it into a solid block.

What do you think?

Also...  Halbach Arrays of permanent magnets look quite interesting.

Title: Can you make motor windings out of Carbon Fiber?
Post by: Geezer on 13/07/2011 08:31:14

You want to reduce the resistance of the windings in a motor as much as possible to keep the efficiency as high as possible. Carbon is fairly resistive (compared to Cu and Al) which is why a lot of resistors were made from it.

Title: Can you make motor windings out of Carbon Fiber?
Post by: CliffordK on 13/07/2011 10:22:03

Thanks,
I just found the electrical conductivity/resistivity of Graphite (at 20°C)

http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity

Silver    1.59×10⁻⁸ [Ω·m]
Copper    1.68×10⁻⁸ [Ω·m]
Aluminum 2.82×10⁻⁸ [Ω·m]
Graphite (Perpendicular to basal plane) 2.5 to 5.0×10⁻⁶ [Ω·m]
Graphite (Parallel to basal plane) 3.0×10⁻³  [Ω·m]

I thought it was supposed to be better than that (the smaller the number the better).  So, efficiency would be down and heat would be up with graphite or carbon fiber. 

I see that even aluminum would generate significantly more heat than the copper.