Vacuum switching tube

摘要

Previously known vacuum switching tubes having a fixed contact and a contact which can move by means of a spring bellows require a large contact force in the connection phase since the contacts must not open in the event of a short-circuit connection current, in order to avoid the contact surface welding. Until now, this increase in contact pressure which was necessary only for the short-circuit connection current was applied permanently during the connection time by the drive of the vacuum power circuit breaker. In the case of a vacuum switching tube 1 having a fixed contact 2 and a contact 3, which can be moved by means of a spring bellows 14 in an evacuated switching chamber 8, both contacts 2 and 3 being arranged on the same side on the mounting plate 10 of the switching chamber 8, a narrow current loop is formed by the contact 3 which moves in a straight line and makes contact on the inside of the double-bent fixed contact 2 by means of a rotary movement, the magnetic current forces of which current loop produce the necessary contact pressure even in the case of very severe short-circuit connection currents, so that the closed contacts cannot lift off and welding of the contact surface is prevented. Vacuum switching tubes for vacuum power circuit breakers in the medium-voltage range up to 10 kV for conventional and compressed-gas-insulated medium-voltage switching installations. <IMAGE>