2,785 research outputs found
Convection Heat Transfer and Flow Calculations Suitable for Electric Machines Thermal Models
No full textThis paper deals with the formulations used to predict convection cooling and flow in electric machines. Empirical dimensionless analysis formulations are used to calculate convection heat transfer. The particular formulation used is selected to match the geometry of the surface under consideration and the cooling type used. Flow network analysis, which is used to study the ventilation inside the machine, is also presented. In order to focus the discussion using examples, a commercial software package dedicated to motor cooling optimization (Motor-CAD) is considered. This paper provides guidelines for choosing suitable thermal and flow network formulations and setting any calibration parameters used. It may also be considered a reference paper that brings together useful heat transfer and flow formulations that can be successfully applied to thermal analysis of electrical machine
TEFC Induction Motors Thermal Models: A parameter Sensitivity Analysis
No full textWith the increasing pressures on electric motor manufacturers to develop smaller and more efficient electric motors, there is a trend to carry out more thermal analysis in parallel with the traditional electromagnetic design. It has been found that attention to thermal design can be rewarded by major improvements in the overall performance. Thus, there is a requirement for accurate and reliable thermal analysis models that can be easily incorporated into motor design software. In this paper, emphasis is given to thermal sensitivity analysis of totally enclosed fan-cooled induction motors. In particular, thermal parameters are modified and their effects on the temperature rise shown. The results are useful for identifying the most important thermal parameters and enable robust designs to be developed that are insensitive to manufacturing tolerances
Torque prediction using the flux-MMF diagram in AC, DC, and reluctance motors
No full textThis paper uses the flux-MMF diagram to compare and contrast the torque production mechanism in seven common types of electric motor. The flux-MMF diagram is a generalized version of the flux-linkage versus current (ψ-i) diagram for switched-reluctance motors. It is illustrated for switched-reluctance, synchronous-reluctance, induction, brushless AC, brushless DC, interior PM and commutator motors. The calculated flux-MMF diagrams for motors with the same electromagnetic volume, airgap, slotfill, and total copper loss are shown and are used to compare the low-speed torque and torque ripple performance. The motor designs used were reasonably optimized using a combination of commercially available motor CAD packages and finite-element analysis
Convection Heat Transfer and Flow Calculations Suitable for Analytical Modelling of Electric Machines
No full textExperimental assessment of end region cooling arrangements in induction motor endwindings
No full textAssessment of Fractional and Small Power Three Phase Induction Motors for Conveyor Applications
No full texton conference CD-RO
End space heat transfer coefficient determination for different induction motor enclosure types
No full textIn this paper, the determination of the end space induction motor heat transfer coefficients is presented, and the methodologies used are examined closely. Two "ad hoc" prototypes have been built and a test bench completed. This paper reports the setup of the test procedures and results obtained in detail. As the end windings are the hottest points of the motor, particular care has been devoted to the determination of the heat transfer coefficient concerning the end-winding structure. The results obtained are of fundamental importance for the determination of the thermal resistances between end windings and end caps. These can then be used in thermal networks usually adopted in thermal model analysis
Influence of Different End Region Cooling Arrangements on End-Winding Heat Transfer Coefficients in Electrical Machines
No full textDesign metrics for evaluating the propulsive efficiency of future ships
No full textThere is an increasing need for the ship design process to take account of environmental issues such as the emission of greenhouse gases and the likely extension of a carbon dioxide charging mechanism to international shipping. These issues, together with the need for economic viability, provide further incentives to improve the efficiency of propulsion of ships. The main components of powering are firstly reviewed. Individual components and other power saving devices are identified which should contribute to improvements in the overall efficiency of propulsion. Suitable design metrics and procedures, taking into account economic and environmental factors, are recommended for the design of future ships
Brief note: some observations on oscillating tangential forces and wear in general plane contacts
No full textFor general plane contact of elastically similar materials, including cases where there are multiple regions of contact, general properties of the partial slip solution for conditions of constant normal force and monotonically increasing shearing force have been found recently by the first author. An extension is given here to cover the unloading and cyclic loading cases. Further, it is shown that, if the tangential load varies between two fixed limits, the region of stick does not change, even if relative microslip causes wear, changing continuously the profile of the indenter. The contact area will change, but wear will not enter the original region of adhesion. The theoretical limit to which wear will eventually, asymptotically proceed is established, viz. almost complete contact over what is the initial stick zone, although it may, in practice, take a long time to reach this state
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