I am trying to build speed control for 500W synchronous, single-phase AC induction motor. It is for a fan in my greenhouse.
I am trying to verify it on breadboard with resistive load (100W lightbulb). The zero crossing detection circuit works well, but TRIAC trigerring does not work.
R5 is set such that there is ~12mA current going through the LED in the optotriac. It is above maximum triggering threshold for MOC3052 and well below its current rating (60mA)
R8 is set such that the maximum current through the optotriac is always below 1A limit (on 230VAC mains)
I have tried with BT139-800E TRIAC (on schematic, with sensitive gate) as well as with BTA140-800
Where have I gone wrong? Could you recommend robust/reliable triggerring circuit?