Solid-State Switching Devices for Switching Motors Solid-State Contactors 3RF24 solid-state reversing contactors, three-phase Maximum permissible switching frequency depending on the starting time t a and the ON period t OP I = 7,2 a I e I = 1 b I e 10000 Operating frequency 1/h 1000 Starting time 100 t = 0,05 s a t = 0,1 s a t = 0,2 s a t = 0,4 s a t = 0,8 s a t = 1,6 s a t = 3,2 s a NSB0_01784 10 0,01 0,1 1 10 100 1000 in s OP t For motors with a starting current of 4 to 7.2 times the rated current and with a full load I = 7,2 a I e I = 0,6 b I e 10000 Operating frequency 1/h 1000 Starting time 100 t = 0,05 s a t = 0,1 s a t = 0,2 s a t = 0,4 s a t = 0,8 s a t = 1,6 s a t = 3,2 s a NSB0_01785 10 0,01 0,1 1 10 100 1000 in s OP t For motors with a starting current of 4 to 7.2 times the rated current and with a 60 % load 64 Siemens · 2009