hi..!

I need guidance. is the first time that I work with SCRs

I have to build a 3-phase controlled rectifier.

and don't know how to turn on & off the SCRs..

 

Check this thread ...

http://forum.allaboutcircuits.com/showthread.php?t=15339

 

thanks.. i know the theory but no the practice.. so, i need to build a control
circuit for the SCRs and i don't have idea of what to do..

 

Search on SCR drivers. You will have to do a lot of homework, as a complete operating controller is not simple.

 

all i need is make a train of pulses for this combination:

T1 T2 ; T2 T3 ; T3 T4 ; T4 T5 ; T5 T6 ; T6 T1

and the firing angle have to be variable

 

all i need is make a train of pulses for this combination:

T1 T2 ; T2 T3 ; T3 T4 ; T4 T5 ; T5 T6 ; T6 T1

and the firing angle have to be variable

As you pointed out earlier - that's theory.

Scratch building a 3-phase controller is a reasonable challenge. Unless you are compelled to build this you would save a lot of time if you buy a dedicated control board off the shelf.