Cooling of Rotating Electrical Machines: Fundamentals, modelling, testing and design

Cover
Contents
List of figures
List of tables
About the Authors
Nomenclature
1 Introduction
2 Fundamentals of heat transfer
2.1 Conduction heat transfer
2.1.1 Fourier’s law
2.1.2 Thermal conductivity
2.1.3 Thermal conduction in one dimension at steady state
2.1.4 General conduction equation
2.1.5 Thermal contact resistance
2.1.6 Boundary conditions
2.1.7 Solution of steady-state heat conduction problems in two and three dimensions
2.1.8 Transient heat conduction
2.2 Convection heat transfer
2.2.1 Physical processes taking place in a convection
2.2.2 Correlations of heat transfer coefficient
2.3 Radiation heat transfer
2.3.1 Nature of thermal radiation
2.3.2 Heat transfer due to radiation
2.3.3 Combined radiation and convection (the radiation heat transfer coefficient)
2.4 Extended surfaces (fins)
2.4.1 Introduction
2.4.2 Fin efficiency
2.4.3 Fin effectiveness
2.5 Heat exchangers
2.5.1 Introduction
2.5.2 Overall heat transfer coefficient
2.5.3 Effectiveness-NTU approach
2.6 Convective heat transfer enhancement
2.7 Heat transfer with a phase change (heat pipes)
2.8 Heat transfer in an annular gap
2.8.1 Annular gap with no axial flow
2.8.2 Effect of slotted surfaces in the annular gap
2.9 Heat transfer in rotating ducts
References
3 Fundamentals of fluid flow
3.1 Basic principles of fluid flow
3.1.1 Viscosity and boundary layer
3.1.2 Navier–Stokes equations
3.1.3 Dimensional analysis and dimensionless parameters
3.2 Flow in ducts
3.2.1 Pressure loss
3.2.2 Flow separation pressure loss
3.3 Fans and rotor driven pressure gains
3.3.1 Euler’s turbomachinery equation
3.3.2 Fan’s laws
3.4 Flow in the air gap
3.4.1 Rotational pressure losses in the air gap
3.4.2 Frictional pressure loss
3.4.3 Entrance pressure loss
3.5 Flow in rotating ducts
3.5.1 Frictional pressure loss
3.5.2 Entrance pressure loss
3.5.3 Flow exits from rotating ducts
3.6 Flow over rotating discs
References
4 Thermal modelling of electrical machines
4.1 Modelling technique – lumped parameter thermal network
4.1.1 Coil’s anisotropic thermal conductivity
4.1.2 Winding heat transfer
4.1.3 End-space cooling
4.1.4 Bearing losses and heat transfer
4.1.5 Lamination stack heat transfer
4.1.6 Interfaces
4.1.7 Machine losses
4.2 TENV cooling
4.3 TEFC cooling
4.4 Open ventilated cooling
4.5 Close circuit cooling with heat exchanger
4.6 Housing water jacket cooling
4.7 Sleeve with flooded stator cooling
4.8 Oil spray cooling
References
5 Advanced computational methods for modelling ventilation and heat transfer
5.1 Finite-element methods
5.1.1 Stranded random wound winding
5.1.2 Bobbin stranded wound winding
5.1.3 Hairpin winding
5.1.4 Pre-formed wound winding
5.1.5 Litz wires
5.2 CFD
5.2.1 Introduction to CFD
5.2.2 Using CFD
5.2.3 Specific issues concerning the application of CFD to electrical machines
5.2.4 Examples of application of CFD
References
6 Thermal test methods
6.1 Measurement methods
6.1.1 Temperature measurement
6.1.2 Heat flux measurement
6.1.3 Air flow measurement
6.1.4 Liquid flow measurement
6.2 Winding insulation system thermal conductivity
6.3 Motor losses
6.3.1 Measurement of windage losses
6.3.2 Calorimetry for measurement of total loss
6.4 Thermal model calibration
6.5 Thermal model calibration using a short transient test
References
7 Application of design methods (case studies)
7.1 Thermal management of electrical insulation system
7.1.1 Slot liner
7.1.2 Impregnation resin
7.2 Totally Enclosed Non-Ventilated cooling
7.3 Totally Enclosed Fan-Cooling
7.4 Open ventilated cooling
7.5 Close circuit cooling with a heat exchanger
7.6 Housing water jacket cooling
7.7 Sleeve with flooded stator cooling
7.8 Oil spray cooling
7.9 High-Performance machine with multiple cooling methods
References
Index
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