B. The lriflce of Contact Parameters on 50%
Breakdown Voltage U50
Within the contact gaps 1O�50mm, the inflence of
contact parameters include contact radius of curvature
contact surface roughness, contact diameter and o�
breakdown characteristics was shown in Fig.5�Fig.7.
Fig.5 shows the relationship between contact radius of
curvature and the 50% breakdown voltage Uso of vacuum
interrupter. Uso of vacuum interrupter with contact radius
of curvature 2mm was signifiantly higher than that of
vacuum interrupter with contact radius of curvature 6mm.
Fig.6 shows the relationship between contact surface
roughness and the 50% breakdown voltage Uso of
vacuum interrupter. The 50% breakdown voltage of
contact roughness 1.61l was close to that of contact
roughness 3.2ll. Fig.7 shows the relationship between
contact surface roughness and the 50% breakdown
voltage Uso of vacuum interrupter. Th 50% breakdown
voltage of the contact diameter 60mm was close to that
of contact diamter 75mm.