| 摘要 |
An elongated substrate made of an electric insulating material carries an elongated conductive track made of aluminium which has a constriction in its centre part in order to increase the heating of the said centre part with a view to reducing as much as possible the volume of material to melt. The ends of the track each comprise an annular part which partially covers a nickel or aluminium pad. The connection and cooling of the ends is carried out by connection brackets. This fuse is calculated in such a way that for a rated current IN, a maximum temperature variation DELTA T and a length of the electric conductor designated 2b, thermal equilibrium is obtained when the relationship between the cross section S of the said conductor and that S' of the base material corresponds approximately to: S= rho 'th. rho e.b2.IN2/2S'. DELTA Tmax where rho 'th is the thermal resistivity of the substrate and rho e the electrical resistivity of the conductive track. |
