Commutating nanotubes

Researchers at Rice University and the University of Oulu in Oulu, Finland, have discovered that carbon nanotubes could improve the performance of electrical commutators that are common in electric motors and generators.

The research, which appeared online in the journal Advanced Materials, found that brush contacts made of carbon nanotubes had 10 times less resistance than the carbon-copper composite brushes commonly used today.

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. They are an integral part of commutators used in many battery-powered electrical devices, such as cordless drills.

Rice's Prof Pulickel Ajayan, said: 'The findings show that nanotubes have a great deal of practical relevance as brush contacts.

'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.'