<div class="htmlview paragraph">Failure of electronic equipment in the alternator system will occur only under fault conditions. Overvoltage levels generated by the alternator and external equipment are discussed. Safe operation can be ensured by high voltage rating or by absorbing energy to reduce the transient voltage. These two methods are compared and transient energy measurements described. Problems in defining a precise specification for the necessary level of protection are stated and proposals made for an acceptable specification based upon experience.</div>