Carbon nanotubes could considerably improve efficiency of electrical motors

Carbon nanotubes for better electric motor efficiency

Finnish researchers have built the world’s first prototype electrical motor using carbon nanotubes in a bid to enhance performance.

The innovative motor, developed by researchers at the Lappeenranta University of Technology (LUT), uses carbon nanotube yarn in the motor windings, instead of conventionally used copper wires.

The team believes that using carbon nanotubes could lead to development of considerably lighter and more efficient electric drives.

"If we keep the electrical machine design parameters unchanged and only replace copper with future carbon nanotube wires, it is possible to reduce the Joule losses in the windings to half of the present-day machine losses,” explained Professor Juha Pyrhönen, who led the design of the prototype at LUT.

“Carbon nanotube wires are significantly lighter than copper and also environmentally friendlier. Therefore, replacing copper with nanotube wires should significantly reduce the CO2 emissions related to the manufacturing and operating of electrical machines. Furthermore, the machine dimensions and masses could be reduced. The motors could also be operated in significantly higher temperatures than the present ones,"

The prototype motor generating 40W of power has nearly 70 per cent efficiency while rotating at 15,000rpm.

To improve performance of electrical motors, researchers need to increase conductivity of wires in the motor windings. Cooper is frequently used in all types of electrical machines as it provides the second best conductivity of all metals at room temperature. In spite of that, a large proportion of the electrical machine energy losses occur in the copper windings.

As conductivity of carbon nanotubes exceeds that of all metals, the material seems to be a likely contender on the way towards more efficient electrical devices.

"In the industry, the number of electrical motors is enormous: there can be up to tens of thousands of motors in a single process industry unit. All these use copper in the windings. Consequently, finding a more efficient material to replace the copper conductors would lead to major changes in the industry," said Prof Pyrhönen.

The Finnish prototype motor uses carbon nanotube yarns spun and converted into an isolated tape by a Japanese-Dutch company Teijin Aramid, which has developed the spinning technology in collaboration with Rice University, USA.

The industrial applications of the new material are still in their infancy. The researchers believe that scaling up the production capacity together with improving the yarn performance will facilitate major progress in the future.

Electrical machines are ubiquitous in everyday life. In a single-family house alone there can be tens of electrical machines in various household appliances such as refrigerators, washing machines, hair dryers and ventilators.

Improving their efficiency would thus have a direct effect not only on the households’ utility bills but also on their carbon footprint.

 

Watch a short video demonstration of the technology:

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