I have designed a dimmer control Circuit to control the relay of inductive AC load, and also using the same to control even the resistive AC load. This is working fine for both AC inductive load as well as AC resistive load. I have designed two such circuits in my design. This is all working good when I use only either of the load at once (i.e either AC load or DC load), but when I tried to control both the loads simultaneously i.e AC resistive load and AC inductive load. the AC Resistive load (Incandescent Bulb) it is flickering. For my Ckt I am using RB 2W10, 4N35 Orto coupler, MOC3021, BT138 Triac, and using a Zero cross detection in AC I am triggering the Triac as needed for intensity. Please help me how can I overcome this problem.
Interesting, can you post a schematic?
I'm not a power electronics guy by any stretch, but one thing to note: When adding a resistive load in parallel to an induction load, it changes the total load power factor. Again, not sure if that helps any (probably not), but I thought I'd throw that out there.
I'm going to guess some noise on the power line from the switching inductive load is fouling-up your zero-cross detection... It doesn't take noise near the zero-crossing to get multiple zero-crossings. Try shifting the threshold to somewhere around 15-45 degrees and then calculate (from the line frequency) when the next zero crossing is coming (or the next two zero-crossings if you're only detecting one point per cycle). That might require some experimentation.
Did you do anything special to handle inductive loads? I've made a dimmer, but never a motor-sped controller and I know they are somehow different.