Three-phase AC solid-state relay (hereinafter referred to as three-phase SSR)

is a collection of three single-phase AC solid-state relays, and uses a single input terminal

to directly switch the three-phase load, which can easily control three-phase AC motors, 

heaters, etc. Three-phase load. The three-phase ordinary SSR uses three triacs as the output 

switch contacts of the A, B, and C three-phases.