Major generator failure concerns are over-excitation during load-rejection wherein V/F ratio could be excessive and dead generator excitation protection. Increase in voltage/frequency ratio subjects a generator to higher flux-density level than it's designed for. Sudden load throw-off in the grid increase voltage at the generator terminal. The increased V/F ratio could cause saturation and inducement of stray flux in the generator's magnetic core. In turn, it leads to overheating and winding insulation failure.