Abstract: This article introduces the analysis of the cause to abnormal noise of CDQ dedusting fan and its solutions．In this paper，the vibration characteristics were thoroughly studied based on actual situation on site，and the causes of various possible faults were eliminated．It was diagnosed that the main reason for the abnormal noise of the CDQ dedusting fan for coke screening was a loose fit between the motor drive end bearing and its mating shaft or hole．

Key words: Abnormal motor noise, Spectrum analysis, Vibration characteristics