LAST STEP SWITCH AND METHOD FOR OPERATING A LAST STEP SWITCH

摘要

Load stepper switch (10) for uninterrupted switching between winding taps (N1, .NJ, .NN) of a step transformer (20), comprising:a load changeover switch (40) for switching from a first fixed contact (11) to a second fixed contact (12) of the load stepper switch (10),one selector (30) for powerless selection of fixed contacts (11, 12),a first control unit (14), where:the load switch (40) has a plurality of semiconductor switching elements (47, 48) and a plurality of mechanical switching elements (43, 44) for switching;the voter (30) has a first voter arm (31) and a second voter arm (32), which can be operated independently and can contact each of the fixed contacts,the first control unit (14) is equipped to trigger a switching command and to operate the first selector arm (31) and the second selector arm (32) and the majority of mechanical switching elements (43, 44) by means of a motor drive (13);wherein the load step switch (10) comprises a second control unit (15) designed to operate the plurality of semiconductor switching elements (47, 48);whereduring switching, the first control unit (14) actuates the motor drive (13) depending on the second control unit (14).