Abstract: A contact structure for a vacuum circuit breaker has an electrically insulating vacuum vessel, fixed and movable contact units sealed in the vacuum vessel and shield members surrounding the fixed and movable contact units in the vacuum vessel. Particles of a metal are applied to at least a part of the inner surface of the vacuum vessel.

Abstract: A cylindrical coil electrode incorporated in a vacuum interrupter comprises a cylindrical body having an opening at one end thereof, two electrical connections provided between the edge surface of the opening of the cylindrical body and a main electrode, two arcuate slits formed on the cylindrical body between the two electrical connections, two arcuate current paths formed in the cylindrical body by the arcuate slits beginning as a respective electrical connection and ending at a rod, and two current blocking slits formed on the cylindrical body at positions where one end of each of the current paths laps the other end of the other current paths. Because of the above structure, one-turn current flows throughout the current paths so that a uniform axial magnetic field can be applied to the main electrode, and an arc current can be uniformly distributed over the entire surface of the main electrode, thereby improving the current interruption performance of the vacuum interrupter.