抄録
Electromagnetic forces of two spiral type electrodes (type A and type B) in vacuum circuit breakers were analyzed in 3 dimensions by FEM (Finite Element Method). Then, these electromagnetic forces were related to the results of current interrupting ability tests. The analysis showed that an arc was ignited on contact electrode type A experienced 0.3 to 2.9 × 10-7 N/A2 circumferential electromagnetic force and 1.0 to 2.1 × 10-7 N/A2 radial electromagnetic force. An arc was ignited on contact electrode type B also experienced 0.0 to 1.3 × 10-7 N/A2 circumferential electromagnetic force and 1.1 to 2.2 × 10-7 N/A2 radial electromagnetic forces.
It was concluded from current interrupting tests that electrode type A had an current interrupting ability of 49.0 or 58.6 kA and electrode type B had an ability of 31.2 or 32.7 kA. Comparison of the current interrupting ability with the electromagnetic forces experienced showed the larger the electromagnetic forces, the higher the current interrupting ability.
