Vacuum switching tube

摘要

In the case of a vacuum switching tube having two main contact systems (2, 3) which are connected in series within a common housing (1) via a coil (35) in order to produce an axial magnetic field, the switching power has until now been only low. In addition, the coil (35) was subject to a continuous rated current load and heating. The internally located contact pieces (4, 5) of the main contact systems (2, 3) of the vacuum switching tube are combined with screening bodies (23, 24) to form axially moving structural units (30, 31) which form an auxiliary contact system (32) which is connected in parallel with the coil (35). The coil (35), which jointly and coaxially surrounds both main contact systems (2, 3) is not connected in series with the main contact systems (2, 3) via this auxiliary contact system (32) until switching off occurs. Since the separate switching chambers (46) formed by means of the structural units (30, 31) are sealed with respect to one another and the axial magnetic field connected via the auxiliary contact system (32) is particularly effective, high currents can be coped with with low contact erosion and high recurring voltages. In addition, the heating of the vacuum switching tube when carrying the rated current is only low. Vacuum switching tubes having double interruption for high currents and voltages for use in conventional and compressed-gas-encapsulated medium-voltage and high-voltage switching installations, switches (circuit breakers) for railway electrical power supplies. <IMAGE>