It really depends on the motor you have, as this unit used different motors throughout it's life cycle. Per the Manual for this model, "Find connection diagram on back side of the cover or on motor nameplate and reconnect to desired voltage as indicated on diagram. WARNING: All wiring must be by a qualified electrican".
Obviously if it's rubbed off or scratched off, the only recourse is to contact a technical service rep with Campbell Hausfeld directly, as they made this unit for Home Depot (a.k.a. Husky).
