Voltage surges in excitation circuits of contactless synchronous alternators-causes and prevention

There are many potential causes of transient conditions leading to overvoltages in contactless synchronous alternators. One of them is faulty synchronizing. The authors investigate many cases where, due to such a cause, serious damage to the exciter armature winding took place after the breakdown of the diode. The analysis of conditions leading to the voltage surges during connection of the generator to the system is presented as well as suggestions of how to avoid them.