As far as the power outage that started it all, it most likely had a voltage spike that caused all these issues. Or (less likely) power was repaired and phases got reversed on the utility side. The manual is a little vague, but the F21 "overload relay" appears to be a circuit breaker that you should be able to visually check (if it has a trip flag) and hopefully can just reset. https://www.e-pneumatic.com/media/pdf/atlas/atlas-copco-ga-45-pdf.pdf