الفهرس 
1.3.Various Types of IM FaultsOnly 14 pages are availabe for public view
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Abstract
Induction motors (IMs) play a very important part in the safe and efficient running of any industrial plant. A variety of faults can occur within three-phase IMs during normal operation.Several faults, such as rotor cage malfunctions, rotor eccentricity or inter-turn insulation breakdown can result in a complete breakdown of the machine if the progress of the fault is not detected. The two common types of stator faults that occur in IMs are the grounded fault and the stator inter-turn short circuit. The stator turn-to-turn fault is one of the most destructive electrical faults in IMs. Early detection of these faults will help to avoid costly breakdown.Accordingly, this thesis presents a mathematical model for simulation of three-phase IMs having inter-turn short circuits in the stator winding. Simulation results from the proposed model are compared with experiments carried out on a specially rewound 3-phase squirrel cage induction motor with taps to allow different number of turns to be shorted. The model has been successfully used to predict the transient and steady state behavior of the induction motor with short-circuited turns, and to test stator fault diagnostic algorithms operating in real time.The results show good agreement between the measurements and the simulated ones obtained from the proposed model, which supports the validity of such a model.Moreover, a proposed scheme for detecting turn-to-turn faults in the stator windings of squirrel cage IMs and estimates the fault severity is developed using feedforward Artificial Neural Networks (ANNs). The proposed detector is implemented using a digital signal processing board DS1003 interfaced with a multi input / output board DS2201. This detector can be successfully used to discriminate turn-to-turn faults from those normal operating conditions that associated with either unbalanced voltage feeding or unbalanced loading.These conditions represent a challenge for other similar fault detectors due to the corresponding unbalance resulting from the turn-to-turn fault itself. Moreover, the detector is able to classify the corresponding faulty phase correctly. For training and testing purposes, a dedicated turn-to-turn fault simulation is prepared with MATLAB. Results of both simulation and experimental investigations corroborate the superior performance of the proposed detector.