Abstract: A multibreak puffer-type circuit-breaker having a cylindrical enclosure filled with pressurized gas, such as SF6 and including a plurality of staggered arc-extinguishing units electrically connected in series. Closing resistors associated with each unit extend cross-wise to the longitudinal direction of the enclosure and are arranged in spaces between the main and auxiliary contacts. The resistors are operated by an auxiliary control rod so as to be inserted during a closing operation prior to engagement of the main contacts.

Abstract: The contact structure for a puffer-type compressed-gas circuit interrupter comprises a pair of elongated aligned axially separable contacts one of which is hollow and has an end portion provided with a plurality of axially extending, circumferentially spaced-apart contact fingers adapted to resiliently grip the other contact in telescoping relation therewith. The fingers are surrounded by a snugly sleeve ending short of the tips of the fingers permitting the puffer mechanism to direct a radial (cross-blast) jet of arc-extinguishing gas through the interstices between said tips exhausting subsequently through the interior of the tubular contact. The sleeve screens off the residual, major part of the length of the fingers to prevent a radial flow of gas therebetween at this level. It has been found that this arrangement provides an unexpected increase in the breaking power of the apparatus as compared to contact structures having sleeves covering the total length of the contact fingers or no sleeves at all.