The following are included in this chapter: a comprehensive formulation of the Maxwell's equations; the finite element formulations; an efficient approach to the implementation of broken bar, eccentricity and short-circuit faults in an FEM package; a discussion of the adjustments in terms of selecting a proper time step and mesh size for simulations; the inclusion of a magnetic field analysis of induction motors by providing two examples, a cage and a wound rotor (the dimensions and materials are also provided so that readers might implement the same models in their own packages); and the study of the flux density variations in different faulty conditions and various motor parts including the stator yoke, the stator teeth, the air gap, the rotor teeth and the rotor back-iron.

Chapter Contents:

• 6.1 Introduction
• 6.2 Electromagnetic field equations
• 6.3 Magnetic vector potential, magnetic scalar potential, current vector potential
• 6.4 T⃗-Φ Formulation
• 6.5 A⃗-V Formulation
• 6.6 Coupled magneto-static and eddy current-field problem
• 6.7 Transient-with-motion formulation
• 6.8 Finite element method
• 6.8.1 Material modeling
• 6.8.2 Magnetic loss calculation
• 6.8.3 Mesh generation
• 6.8.4 Set-up system of equations
• 6.9 Induction motor examples
• 6.9.1 Healthy motor operation
• 6.9.2 Broken bar motor operation
• 6.9.3 Eccentric motor operation
• 6.9.3.1 Static eccentricity
• 6.9.3.2 Dynamic eccentricity
• 6.9.4 Short-circuited motor operation
• 6.9.4.1 Implementing skewing effect
• 6.9.4.2 Modeling rotor interturn fault
• 6.9.4.3 Modeling stator interturn fault
• References

Inspec keywords: rotors; Maxwell equations; stators; induction motors; magnetic fields; finite element analysis

Other keywords: stator yoke; induction motors; flux density variations; finite element implementation; air gap; short-circuit faults; magnetic field analysis; rotor teeth; stator teeth; rotor back-iron; Maxwell equations; wound rotor; FEM package

Subjects: Electric and magnetic fields; Asynchronous machines; Finite element analysis