Detection of Backlash Phenomena Appearing in a Single Cement Kiln Drive Using the Current and the Electromagnetic Torque Signature

Fault diagnosis in electromechanical drives has been widely investigated over the last decades, and many diagnostic methods have been proposed based on the reported faults. Additionally to already published works which have dealt with gear faults inside low reduction ratio gearboxes, this paper aims to present a simple and effective method for the early diagnosis of evolving faults in a high reduction ratio gear transmission system used in cement kiln drives. The under study system basically consists of a three-phase induction motor mechanically connected to a gearbox. The output shaft of the gearbox drives a gear pinion which, in turn, rotates a girth gear rim surrounding the cement kiln. The identification of mechanical vibrations due to backlash phenomena appearing between the pinion gear and the girth gear rim of the kiln is realized using the motor current signature analysis and processing the motor electromagnetic torque. The proposed diagnostic method is presented, analyzing the experimental results from an under-scale laboratory simulating system.