Novel approach to analytical modelling of steady-state heat transfer from the exterior of TEFC induction motors

Abstract

The purpose of this paper is to propose a novel approach to analytical modelling of steady-state heat transfer from the exterior of totally enclosed fan-cooled induction motors. The proposed approach is based on the geometry simplification methods, energy balance equation, modified correlations for forced convection, the Stefan-Boltzmann law, air-flow velocity profiles, and turbulence factor models. To apply modified correlations for forced convection, the motor exterior is presented with surfaces of elementary 3-D shapes as well as the air-flow velocity profiles and turbulence factor models are introduced. The existing correlations for forced convection from a short horizontal cylinder and correlations for heat transfer from straight fins (as well as inter-fin surfaces) in axial air-flows are modified by introducing the Prandtl number to the appropriate power. The correlations for forced convection from straight fins and inter-fin surfaces are derived from the existing ones for combined heat transfer (due to forced convection and radiation) by using the forced-convection correlations for a single flat plate. Employing the proposed analytical approach, satisfactory agreement is obtained with experimental data from other studies.

Investigation of Heat Loss from the Finned Housing of the Electric Motor of a Vacuum Pump

“…Unrealistic assumptions are applied in many studies where steady-state heat transfer in motor is modelled. These assumptions strongly affect the accuracy of the models [9]. The aim of this article is to present a method of evaluating the heat loss by determining the coefficient of convective heat transfer from the housing to the environment, and determining the conduction heat flux that is transferred through the motor housing.…”

Bearing fault detection by four-band wavelet packet decomposition

“…Therefore, condition monitoring and preventive maintenance of such motors is so vital. Sound [1], thermal [2][3][4], vibration [1,5], and current signature analysis [6] are some of the methods used in motor condition monitoring and preventive maintenance. Vibration analysis is the most effective approach in detecting the mechanical faults such as bearing problems since the fault related signals are directly obtained by placing vibration transducers in proper locations.…”