A closing phase that makes smallest an energization flux error at a connection input point is calculated based upon a residual flux of the first closing phase and the preliminarily given pre-arc characteristic and closing time deviation characteristic of a three-phase circuit breaker, so that the calculated phase value is set as a target closing phase of the first closing phase. A digital signal in which a plurality of digital signal types including an audio signal are multiplexed and contained in blocks as the smallest reproduction unit of VOBU contains a compressed video signal pack V_PCK which has been compression-coded by way of predictive coding in the time axis direction and an audio signal pack A_PCK. Each of the mandrel cups and cupping arms are disposed radially about the cupping arm turret. The cover fastener has one or more releasable closures, and at least one of the releasable closures includes a fluked tab interlock locking tab and slot structure, wherein the fluked tab is on one end of the cover and the slot is proximate the opposite end of the cover and parallel to the fluked tab. Preferably, at least one of the first material and the second material is a magnet for magnetic attraction between the at least one piece of the first material and the at least one piece of the second material.