Changsha Metro Line 5, China's first metro line with propulsion system featured with permanent magnet, was officially put into operation on July 3, marking the beginning of the permanent magnet era for China's metro. The permanent magnet propulsion system takes use of the material of USES samarium cobalt permanent magnet, which is developed by China Institute of Electronics Acoustics Optoelectronics (CIEAO).
The samarium cobalt permanent magnet material, a high performance rare earth adopted in the permanent magnet propulsion system is characterized by high temperature resistance, high magnetic capability and small volume. In the temperature range of -250 ° C to 350 ° C, it assures extremely strong magnetism and prevents the permanent magnet propulsion system from failure of normal operation due to the loss of magnetism.
"Even a strong man can't pull open permanent magnets in the size of a chess which are held together in their entirety." According to technical experts from CIEAO, permanent magnets made from permanent magnet materials contain huge energy despite their small size. A cylindrical permanent magnet with a diameter of 3.6 cm and a height of about 3.2 cm is attached to both ends of the wire rope, which is respectively attached to the tail of one car and the head of another car, both larger in size and weight. When the front car is in motion, the rear car will be successfully dragged with the help of permanent magnet tension.
"It's not just rail transit, samarium cobalt permanent magnets can also be used in the fields of aerospace, communications, radar, navigation and so on." said the technical experts. Taking the application of permanent magnet traction system as an opportunity, China Institute of Electronics will continue to reinforce the research on rare earth permanent magnet materials, strengthen the promotion of rare earth permanent magnet materials in new energy vehicles, wind power and other fields, and bring more changes to people's travel and life in future
Written by: Li Liangyou
