Three Phase Power Control

Hello everybody ! This is my first post here in Arduino Forum , so I hope i'm posting on the right section. Recently I got some challenge. I need to control power distribution on a three phase system , connected to a resistive load (lamps).

First of all , I thought of using a TRIAC , controlling each of the three phase angle , using zero cross detection and DIAC to trigger the TRIACs (I used one TRIAC for each phase). The problem is: the load is configured on DELTA CONNECTION (see the image below).

Observing on oscilloscope , the THREE PHASE ANGLE CONTROL doesn't work on a connection like that , and physically we can observe strange behavior on lamps.So there is a concept problem. Doing some research on internet , I didn't find anything regarding of power control on DELTA CONNECTION load.

Anyone can help me ? I hope that I was clear enough on my information. If anyone needs any more information , please ask me.

I appreciate all your help !

Add a triac in series with each load, not in the phase lines.

I don't think you did much research on-line. I immediately found this: I searched for "three phase power control".

Delta configuration is more complicated than a "Y" configuration because the power going to any one of the three devices must also flow through the other two devices.


That was going to be my intuition until I realized how bogus it is. The phase-phase voltage
is not affected by any currents flowing (unless the circuit is overloaded).

Of course with heavy loads you should be symmetrically loading the supply, I'm assuming
lamps aren't particularly heavy loads here.