Toshiba's New Vacuum Interrupter for Vacuum Circuit Breaker Doubles High Current Interruption Capability

7 March, 1997

TOKYO--Toshiba Corporation today announced the successful development of a new concept in vacuum interrupters, the key component of the vacuum circuit breakers essential for electric power distribution. Self Arc Diffusion by Electrode applies fundamental research in metallurgy, plasma physics and magnetic field analysis to a new generation of interrupters that double high current power interruption capabilities. Vacuum circuit breakers incorporating new vacuum interrupters, with a range from 7.2kV to 84kV, will be released to the worldwide market from early spring next year.

Toshiba has long been a leader in vacuum interrupter technology. In 1975, the company developed the Axial Magnetic Field vacuum interrupter that today, with "Spiral" and"Contrate", is one of the world's most important electrode technologies. Axial Magnetic Field offers high current interruption performance, in particular above 40kA.

Toshiba has continued to promote development of Axial Magnetic Field and next-generation vacuum interrupters through fundamental research into metallurgy for contact materials, vacuum arc plasma physics, and magnetic field analysis. On the basis of progress made, the company initiated the research project in 1995, with the goal of going beyond conventional Axial Magnetic Field technology to a new kind of high-performance interrupter. As a result of the research project, the company's researchers have filed over 120 patent claims for advances related to interrupters.

In 1965, Toshiba became the first Japanese company to commercialize a vacuum interrupter. Since then, the company's highly reliable vacuum sealing, contact and vacuum-arc control technologies have earned the respect of electric power companies and industry. The company has been the world's top producer of vacuum interrupters for over 30 years, with cumulative production of 2.2 million units. Production last year stood at 120,000 units. The company expects development of Self Arc Diffusion by Electrode technology to reinforce its leadership of the vacuum interrupter industry.

Sample photograph: 12kV-630A-20kA
Conventional Vacuum Interrupter
Outside Diameter:95mm
New Concept Vacuum Interrupter
Outside Diameter:70mm

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