May I verify what will be the effect on the induction motor if it is under excited/over excited during full load run?

 

Induction motors do not require excitation current/voltage.

 

Renato... excitation-voltage equals terminal-voltage minus the stator-winding impedance-drop. The formula is Ve = Vt - Is x Z !

However, excitation-voltage change is not directly proportional to terminal-voltage change, because an 'operating' motor is a constant kVA apparatus... thus an increase in terminal-voltage, Vt, will produce a decrease in stator-current, Is, and vice-versa.

If you would like additional information let us know.

Regards, Phil Corso (cepsicon[at]AOL[dot]com)