Patent ID: 6479778
Filing Date: 2002-11-12
Classification: H01H

Abstract:
A vacuum switch comprising:a pair of windmill-shaped electrodes disposed within a vacuum tube, each windmill-shaped electrode having a circular central portion with a substantially uniform first thickness, a generally annular circumferential contact portion surrounding and contiguous to the central portion and having a second thickness larger than the first thickness, and a plurality of spiral grooves substantially perpendicular to and passing through the thickness of said central portion and said circumferential contact portion, extending from said central portion through said circumferential contact portion, defining windmill portions separated from each other by the grooves, and dividing said central portion into a plurality of windmill portions, wherein said circumferential contact portions have respective contact surfaces brought into contact with each other when said pair of windmill-shaped electrodes are in contact with each other, an electric arc is generated on said contact surfaces when said pair of windmill-shaped electrodes are separated from each other after being in contact with each other with an electrical current flowing through said pair of said windmill-shaped electrodes, and a magnetic flux is generated by an electric current flowing in the electric arc extending between respective circumferential contact portions of said windmill-shaped electrodes, said contact portions and said contact surfaces being shaped so that a component of the magnetic flux parallel to one of said contact surfaces at a distance of 0.5 mm from said contact surface has a magnetic flux density at least equal to 0.01 tesla per 1 kA of electric current flowing between said windmill-shaped electrodes.