THREE-POSITION LOAD ISOLATING SWITCH FOR MEDIUM-VOLTAGE SWITCHGEAR ASSEMBLIES

In order to design a three-position load isolating switch for medium-voltage switchgear assemblies, which three-position load isolating switch can be produced in a cost-effective manner with a compact construction, a three-position load isolating switch (1), for medium-voltage switchgear assemblies having a main contact system, is formed from a first fixed contact (2) and from a second fixed contact (3), said fixed contacts being situated diametrically opposite one another, and from a moving contact (4) which can be rotated by means of a rotary support (7) which is arranged centrally between the first fixed contact (2) and the second fixed contact (3), so as to form a main current path in a first position of the rotatable moving contact (4), so as to form an isolating section in a second position of the rotatable moving contact (4) and so as to form an earthing position with an earthing contact system in a third position of the rotatable moving contact, and also from a secondary current path which is formed from the first fixed contact (2), from the second fixed contact (3), from an arc-quenching contact system (9) and also from a first sliding contact (15) and a second sliding contact (16) for forming a conductive connection to the rotatable moving contact (4) in a rotation angle region of the rotatable moving contact (4), which rotation angle region is located between the first position and the second position, in such a way that, when a rotary movement is initiated in the rotatable moving contact (4), commutation of an alternating current which flows across the switchgear from the main current path to the secondary current path is possible, wherein the rotatable moving contact (4) has means (18, 19, 25) for interrupting the arc-quenching contact system (9), and, when the arc is quenched and a further rotary movement is initiated, the isolating section can be formed.