In view of the problems occurred in the daily electric maintenance of main fans introduced from France and by analyzing the reasons,the improved and preventive measures are carried out,thus effectively guaranteeing safety running of main fans.

This paper introduces the functions of the excitation device in the normal operation of the main fan,and connecting with the actual situation,makes the technical analysis on the faults often occurring in the excitation devices.

To analyze the effect on the others after adjusting the performance of a certain fan when multiple-set main fan unitedly work at the same time,point out the performance changing rules.