Analysis of Eccentric Faults of Induction Motor by Using Shannon Entropy

Abstract

One of the common faults of induction motors which are extensively used in industry and commercial applications is the axial misalignment faults in the motor. In this study, axial misalignment faults of a three-phase squirrel-cage induction motor was analyzed by Shannon entropy. The axial misalignment fault was created by the enlarging of the bearing shell inside the two end-bells of the induction motor. A special designed material manufactured by a 3D printer was placed inside the enlarged bearing shell. In this way, a 0.20 mm offset was created. Induction motor was tested both healthy and with axial misalignment fault under 25%, 50%, 75% and 100% loading conditions. The stator current and vibration signals were recorded for each test case. The validity of the stator current and vibration signals was checked by Fourier analysis. The axial offset effect was evaluated by calculating the entropy values of the stator current and vibration signals of the motor. Then entropy values were calculated for both the healthy and faulty motor. The results show that the axial misalignment faults cause an increase in the entropy value of the vibration signal significantly. The change in the entropy value of the stator current due to axial misalignment faults is not significant. Therefore it is shown that the entropy analysis of vibration signals can be used in the analysis eccentric fault of induction motors. 

Keywords

• Induction Motor,Axial Misalignment Faults,Entropy Analysis,Shannon Entropy

ASENKRON MOTOR EKSENEL KAÇIKLIK ARIZALARININ SHANNON ENTROPİSİ İLE ANALİZİ

Abstract

Sanayide ve işletmelerde yoğun bir şekilde kullanılan asenkron motorların yaygın arızalarından bir tanesi de motorlarda meydana gelen eksenel kaçıklık arızalarıdır. Bu çalışmada üç fazlı sincap kafesli bir asenkron motorun eksenel kaçıklık arızaları Shannon entropisi ile incelendi. Eksenel kaçıklık arızaları asenkron motorun her iki kapağının iç kısmındaki rulman yatakları genişletilerek oluşturuldu. Genişletilen rulman yataklarına üç boyutlu yazıcıdan elde edilen bir burç yerleştirilerek rotorun eksenden 0,20 mm kaçık olarak çalışması sağlandı. Asenkron motor hem sağlam olarak hem de eksenel kaçıklık arızalı olarak %25, %50, %75 ve %100 yük altında çalıştırıldı. Her test durumu için stator akımı ve titreşim sinyalleri kaydedildi. Stator akımı ve titreşim sinyallerinin doğruluğu Fourier analizi ile kontrol edildi. Eksenel kaçıklık arızasının etkisi, motorun stator akımı ve titreşim sinyallerinin entropi değerleri hesaplanarak incelendi. Sağlam ve eksenel kaçıklık arızalı motorun akım ve titreşim sinyallerinin entropi değerleri karşılaştırıldı. Elde edilen sonuçlar; eksenel kaçıklık arızalarının titreşim sinyali entropi değerinde ciddi bir artışa sebep olduğu ancak stator akımı entropi değerinde anlamlı bir değişim göstermediğini göstermektedir. Elde edilen sonuçlardan titreşim sinyalleri entropi analizinin eksenel kaçıklık arızalarının tespitinde kullanılabileceği görülmektedir.

Keywords

• Asenkron Motor,Eksenel Kaçıklık Arızaları,Entropi Analizi,Shannon Entropisi

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