I apologize if you mistook my questions and comments. The comment were purely due to my curiosity.
In post # 19 I asked for the voltages of the pots to see if it was possible to use a digipot. I understood a 5hp motor would not be controlled directly from a panel pot.
From the schematic I believe it may not be possible or at least not straight forward to replace the 10k pot. Digipots have limited voltage capabilities that would seem to exceed those I have investigated.
For the 50k pot it might be possible but unlikely. It would depend on the Rect1 voltage between circuit 29A and 22.
For instance the "AD5171 Digital Potentiometer" is limited to 5V. It would appear the 10k pot would exceed 5v relative to a ground.
I know of no solid state design to replace these pots with something controlled by an Arduino. If I missed something please let me know.
John