Large-capacity vacuum circuit breaker
A large-capacity vacuum circuit breaker that can increase a current shutdown capacity and enables its rated current to be increased includes at least two vacuum circuit breaker units placed side by side and connected in parallel. The two vacuum circuit breaker units are operated by a single common operating unit to concurrently perform current shutdown operations. Each vacuum circuit breaker unit has a vertical magnetic field generating means for generating a vertical magnetic field when an operation to shut down current is performed. The vertical magnetic field generating means is formed by vertical magnetic field electrodes provided in a vacuum container of each of the vacuum circuit breaker unit units or by an external coil provided on the outer circumference of each vacuum container.
1. A large-capacity vacuum circuit breaker comprising:
a first vacuum circuit breaker unit and a second vacuum circuit breaker unit, said vacuum circuit breaker units having the same capacity and being placed side by side and electrically connected in parallel; and
a single common operating unit which operates said first and second vacuum circuit breaker units so as to perform a circuit shut down operation; and
wherein said first and second vacuum circuit breaker units have first and second vertical magnetic field generating means for each generating a vertical magnetic field, said vertical magnetic field being added to an arc generated during current shut down, and
wherein said first and second vertical magnetic field generating means comprise a first external coil on an external surface of a vacuum container of said first vacuum circuit breaker unit and a second external coil on an external surface of a vacuum container of said second vacuum circuit breaker unit, respectively, one end of said first external coil being connected to a second current conductor on the side of said second vacuum circuit breaker unit through a second current collector on the side of said second vacuum circuit breaker unit and the other end of said first external coil being connected to a lower terminal, and one end of said second external coil being connected to a first current conductor on the side of said first vacuum circuit breaker unit through a fist current collector on the side of said fist vacuum circuit breaker unit and the other end of said second external coil being connected to said lower terminal, whereby the currents flowing through said first and second vacuum circuit breaker units during current shut down are equal to each other.