4 channel, 230 V, 8 kW (2 kW/channel) triac circuit docs.

[Adam Szendrey]

Update: The PCB layout is now included.

IMPORTANT!
This unit is only good for the 230 V (200-240) grid, as it creates the power stage supply voltage (around 18-19V, see diagram, a capacitive divider and some diodes, plus an electrolite cap. produces it) from the grid voltage.
BUT (and only) if you make some slight modifications to this divider supply, you can use this unit for 100-120 V too. Or for that matter for 400 V (the triacs are rated for 600 V i think). Though you will have to change the fuses respectively (20 A for 110 V, 5 A for 400 V).

About the circuit diagram.
These drawings are of european standards. But i'm sure all of you who are into electronics will knwo what is what. The transistors, zener diodes are drawn in an older standard. Personally i think this kind is much better than the new....
You will find two hungarian words:
"Tiltas": this lead is for not allowing any of the triacs to ignite upon powering up the circuit. Personally i don't use it. And unless it is absolutely crutial for the triacs NOT to close for a very short time upon powering up the unit, this can be neglected.

"Szinkron": This is the syncron lead.

If you have any questions concerning the components, or the circuit, contact me.

Adam

Ps.: I just looked at the BT138 specs. There are three kinds. 500 V, 600 V, and 800 V. For 400 V use it is strongly advised that you use the 800 V type. Anyway i'm not sure that modifying this circuit for 400 V is a good idea. It is rated for 230 V. Modifying it for lower voltages is safe, but for higher there is a risk.