GB619545A - Improvements in and relating to alternating current switches with arc-extinguishing arrangements - Google Patents

Abstract

619,545. Fluid blast switches. ETABLISSEMENTS MERLIN & GERIN. Sept. 30, 1946, No. 29102. Convention date, Oct. 3, 1945 [Class 38 (v)] An oil circuit-breaker has an explosion pot 3, which by compressing springs 13, 14, can move under the effect of the pressure generated in it by the arc. Fig. 2 shows the position of the explosion pot at the moment when the pressure has reached its maximum immediately after the separation of the contacts 1, 2. A relief port 5 is open to limit the pressure generated and to provide a blast of gas past the fixed contact 1, whilst the transverse blow-out orifices 6 to 9 are masked by the moving contact 2. As the current in the arc drops, the pressure falls and the pot springs back to close the port 5 and open several of the orifices 6 to 9, thus enabling the residual pressure to create a blast across the moving contact and so extinguish the arc at the current zero. The above action may be obtained when using a solid gas evolving material instead of oil. In a modification, Fig. 3 (not shown), the explosion pot has axial blow-out orifices. A method of mounting the explosion pot, Figs. 5, 6 (not shown), provides for its easy removal by releasing a catch and turning the pot so that neck portions of special bolts disengage from slots in the supporting plate. In a further modification, Fig. 4 (not shown), a blow-out orifice is provided by a hollow moving contact instead of by holes in the explosion pot, the final extinction of the arc taking place when the return of the pot causes the moving contact to be flooded with oil.