Activation unit for power switches and protection switches, specially designed as low voltage switches

摘要

In the case of power circuit breakers and protective switches which are of modular construction, the accessory parts should also be as space-saving and compact as possible in order to keep the dimensions of the switch housing within the limits and also to ensure accessibility to the relevant components. In the case of a trip unit (1) for power circuit breakers and protective switches which is designed especially as an undervoltage trip unit, this is achieved in that a switching or tensioning pin (12), which projects from the lock mechanism (8) of the switch to the side, acts on the tensioning lever (9) of the trip unit (1), which lever is constructed as a single-armed lever and pivots about a rotation axis (14) which is arranged on the housing (13) of the trip unit (1) at right angles to the trip plunger (7), and acts by means of at least one pressure point (15), which is located between its free lever end and the rotation axis (14), on the first lever arm (16) of the trip lever (10), which is constructed as a two-armed rocker and is supported on the end of the housing (13) located adjacent to the plunger head (17) of the trip plunger (7) such that it can pivot about a rotation axis (18) which is parallel to the rotation axis (14) of the tensioning lever (9), such that, when it is acted on by the tensioning lever (9), it presses by means of its second lever arm (19) the spring-loaded trip plunger (7) against the trip coil (5), and such that a trip arm (20) is directed against the lock mechanism (8) from the second lever arm (19), which trip arm (20) operates the trip latch (11) on the latching mechanism when the voltage is inadequate so that the switch can remain such that the contacts do not touch and it is not switched on. IMAGE