Solid-State Switching Devices for Resistive Loads Solid-State Relays 3RF21 solid-state relays, single-phase, 22.5 mm ■ Characteristic curves Dependence of the device current I e on the ambient temperature T a and the heat sink resistance R thha $ % & ! $ ' & $ ( ( Type current 20 A (3RF21 20, 3RF20 20) 1) ! " $ % & !
$ ' & $ ( ( ) ! " Type current 30 A (3RF21 30, 3RF20 30) * $ % & ! $ ' & $ ( ( ) Type current 50 A (3RF21 50, 3RF20 50) !
" 1) For arrangement example see next page. 12 Siemens · 2009