What is the function of the current transformer of the thyristor intermediate frequency power supply?

A current transformer is connected to the three wires of the three-phase input of the thyristor intermediate frequency power supply. The main function is to intercept the current signal of each phase. This signal is converted into a voltage signal on the circuit board to control the size of the total current (ie, intercept ), and also provide a threshold signal for over-current (over-current) protection. It is mainly to provide a signal source for over-current protection.