Synchronous Motor Load Angle Meausurement

I want to work on a project which would measure the load angle of a synchronous motor with changing loads. How should I go about it and where should I start? What are the components I need to have for doing it?

I have worked on Arduino based DC motor projects earlier, but interfacing AC motors with Arduino would be a new thing for me, so I'd be much obliged if you can suggest me some knowledge sources or tutorials which would help me out on this project.

Thank you.

What do you expect to be feeding to the arduino to measure the load angle? What component would you need to add to the motor to gain such inputs? Given the input signal, figure out how you would turn that into a usefull measurement, and then see what you could find in the playground that mimics that. Put some code together. Try it out. Then come back and ask some reasonable questions.

Have fun and good luck.