Featured Research

from universities, journals, and other organizations

Nanotube Structures Could Improve Electric Motors

Date:
March 15, 2009
Source:
Rice University
Summary:
Researchers have found that carbon nanotubes can significantly improve the performance of electrical contacts that are common in millions of motors used in a variety of electrical applications. New research concludes that "brush contacts" made of carbon nanotubes had 10 times less resistance than did the carbon-copper composite brushes commonly used today.

Pads of nanotube "forests" were tested as brush contacts.
Credit: P. Ajayan/Rice University

New research from Rice University and the University of Oulu in Oulu, Finland, finds that carbon nanotubes could significantly improve the performance of electrical commutators that are common in electric motors and generators.

The research, which appeared online this month in the journal Advanced Materials, finds that "brush contact" pads made of carbon nanotubes had 10 times less resistance than did the carbon-copper composite brushes commonly used today. Brush contacts are an integral part of "commutators," or spinning electrical switches used in many battery-powered electrical devices, such as cordless drills.

"The findings show that nanotubes have a great deal of practical relevance as brush contacts," said lead researcher Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science. "The technology is widely used in industry, both in consumer gadgets as well as larger electrical machinery, so this could be a very interesting, near-term application for nanotubes." The combination of mechanical and electrical properties of nanotubes makes this possible.

The carbon nanotubes used in the study are hollow tubes of pure carbon that are about 30 nanometers in diameter. By comparison, a human hair is about 100,000 nanometers in diameter. In addition to being small, nanotubes are also extremely lightweight and durable, and they are excellent conductors of heat and electricity.

Because of these properties, the researchers decided to test nanotubes as brush contacts. Brush contacts are conducting pads held against a spinning metal disc or rod by spring-loaded arms. Current is passed from the spinning disc through the brush contacts to other parts of the device.

To test the feasibility of using carbon nanotube brush contacts, the research team replaced the ordinary copper-carbon composite brushes of an electric motor with small blocks that contain millions of carbon nanotubes. Under an electron microscope, these millimeter-square blocks look like a tightly packed forest.

From Ajayan's previous work, the team knew that these nanotube forests react something like a "memory foam" pillow; they regain their shape very quickly after they are compressed.

"This elasticity is something that's not found in existing composites that are used for brush contacts, and that's the essence of why the nanotube brush contacts perform better: They keep much more of their surface area in contact with the spinning disc," said Robert Vajtai, faculty fellow at Rice. Vajtai worked on the study with Ajayan and a group of researchers in Finland led by University of Oulu Researcher Krisztian Kordas.

The team believes that the improved contact between the surface of the spinning disc and the brush accounts for the 90 percent reduction in lost energy.

Co-authors on the paper also included Geza Toth, Jani Mδklin, Niina Halonen, Jaakko Palosaari, Jari Juuti and Heli Jantunen, all of the University of Oulu, and Gregory Sawyer of the University of Florida.

Support for the research was provided by the Academy of Finland, the University of Oulu's Micro and Nanotechnology Center, the Air Force Office of Scientific Research and the Semiconductor Research Corporation.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Cite This Page:

Rice University. "Nanotube Structures Could Improve Electric Motors." ScienceDaily. ScienceDaily, 15 March 2009. <www.sciencedaily.com/releases/2009/03/090310124855.htm>.
Rice University. (2009, March 15). Nanotube Structures Could Improve Electric Motors. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2009/03/090310124855.htm
Rice University. "Nanotube Structures Could Improve Electric Motors." ScienceDaily. www.sciencedaily.com/releases/2009/03/090310124855.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) — When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins