Thank you. Do have any idea where can I find the author?Yes, thats a reverse-engineered version out that is out there, hopefully it is all correct.
Max.
Obrigado = Thank you so mutchIt is post #1
Max.
The popular US manuf. of DC motor drives, KB, traditionally use transformer-less units, The low voltage in some boards are derived from a zener circuit. Some models do however have an control isolation transformer., you hit some good points. No "transformer" on the board as well as more than one opto indicates multiple grounds and not only that, .