> Which is the right way to connect a TRIAC at 400 VAC?
>
> Will it be between the phases or it=B4s to use only one
> phase ( open one phase up ).
>
the fact you even need to ask this question makes me seriously think you
shouldn't be messing with 3 phase mains.

the answer is that a single triac will only switch one of the 3 lives, so
you really need 3 of them (you might get away with two if the load has no
neutral but i wouldn't reccomend it) and all 3 triacs need to be SEPERATELY
opto-isolated from the control circuitry.

-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist