SCR's firing angle

[rave]

hello. can anyone help me? i cant seem to come up with a coding for PIC16f877a to control firing angle of a SCR. any idea is fully apreciate.

[Acetronics2]

Hi, rave

@ 50 Hz ... 0...180° equals 0 ... 10 ms ...

just delay the gate supply from 0 to 10 ms ... after detecting mains zero cross.

NOW

I think a guy called Steve Monfette wrote something about that in the MeLabs Example programs ...

So, ... http://www.melabs.com/

Alain

[rave]

thanks acetronics for ur reply. but still i dun really understand what u mean. can u show me some example of the coding? how do i fire variable angle to the SCR to get variable output?

[rave]

btw, i am making a cycloconverter to control motorspeed. i dont really know how to program my PIC to fire an angle or variable angle for my SCR. please guide me..

[Acetronics2]

Hi,

It's NOT a "Mc Do" drive in here ... too bad : you have to cook your own food ...

We just provide the receipes and the pan. lol

a little effort from you IS necessary ... post #2 !!! ... title is " Dimmer.bas"

Alain

[sougata]

Hi,

In case of a cycloconverter you need to track the phase of the ac input also. I use pulse transformers which fires 8 SCRs to achieve cyclo-conversion and phase angle control. The hardware PWMs are used as a low duty cycle pulse generation AND gated. Mine is for a trainer kit application.