Thermal Analysis of Low-Power Three-Phase Induction Motors Operating under Voltage Unbalance and Inter-Turn Short Circuit Faults

Abstract

Three-phase induction motors are considered to be the workhorse of industry. Therefore, induction motor faults are not only the cause of users’ frustrations but they also drive up the costs related to unexpected breakdowns, repair actions, and safety issues. One of the most critical faults in three-phase induction motors is related to the occurrence of inter-turn short circuits, due to its devastating consequences. The topic of inter-turn short-circuit faults in three-phase induction motors has been discussed over recent decades by several researchers. These studies have mainly dealt with early fault detection to avoid dramatic consequences. However, they fall short of addressing the potential burnout of the induction motor before the detection step. Furthermore, the cumulative action played by an inevitable degree of unbalanced supply voltages may exacerbate such consequences. For that reason, in deep detail, this paper delves into the thermal analysis of the induction motor when operating under these two harsh conditions: unbalanced supply voltages and the presence of the most incipient type of inter-turn short-circuit condition—a short-circuit between two turns only. In this work, the finite element method has been applied to create the faulty scenarios, and a commercial software (Flux2D) has been used in order to simulate the electromagnetic and thermal behavior of the machine for various degrees of severity of the aforementioned faulty modes. The obtained results confirm that the diagnostic tools reported in the literature might not be effective, failing to warrant the required lead time so that suitable actions can be taken to prevent permanent damage to the machine.

Determining an additional diagnostic parameter for improving the accuracy of assessment of the condition of stator windings in an induction motor

“…Studies of classical implementations of temperature methods for diagnosing inter-turn faults of stator windings of an induction motor are reported in [13,14]. Work [13] investigated changes in the propagation of the internal temperature of the engine in the event of an inter-turn short circuit of the stator windings.…”

Development of mathematical models of energy conversion processes in an induction motor supplied from an autonomous induction generator with parametric non-symmetry

“…For this study, a mathematical model has been developed to calculate currents, torque, power losses, temperature rise and derating factor. Similarly, [18] discusses in detail the thermal analysis of IM when operating under these two conditions: unbalanced supply voltage and the presence of turn-to-turn short circuit. In this work, the finite element method was applied to generate fault scenarios, and software was used to simulate the electromagnetic and thermal behavior of the machine for varying degrees of severity of the aforementioned faults.…”

Three-Phase Induction Motors Online Protection against Unbalanced Supply Voltages

“…Nowadays, more than 85% of electric motors used in industry are three-phase induction motors (IMs) [1][2][3][4]. They are widely used due to their reliability, convenience of design, high performance, and overloaded capacity, for different applications such as manufacturing, processing, power systems, transportation, etc.…”