Characterizing the heat transfer on the end-windings of an electrical machine for transient simulations

Abstract

This article presents a method to determine the convective heat transfer coefficient on the end windings of an induction motor. Based on dimensional analysis and heat transfer coefficient values derived by computational fluid dynamics, a correlation between given boundary conditions and the heat transfer coefficient on the end windings has been found.The results can be used in transient simulations of operating cycles. In order to make the application more universal, the approach has been made independent of the characteristics of the fan used for cooling the electrical machine.

Characterizing the convective wall heat transfer on convoluted shapes in the end-region of an induction machine

“…with the reference pressure p 0 , the ideal gas constant for air R s = 287.12 J/kgK and the temperature at the model's air inlet T in in K. The heat capacity c p has been approximated by a so called zero pressure polynomial and the thermal conductivity λ and dynamic viscosity μ have been modeled by the Sutherland formula, as described in [6]. The wall temperature has been defined as T ew = 360 K for the end-windings and T es = 330 K for the end-shield.…”

Dynamic evaluation of the overloading potential of a convection cooled permanent magnet synchronous motor

“…Since the end turns are modelled as single wires, the cooling area available is larger than what is practically achievable, therefore the heat transfer coefficient has to be below 7 W/(m 2 K) in average in order to reduce temperature rise in the machine 50K (Fig. 5) [12], [13]. Similarly the emissivity has to be larger than 0.5 or the conductivity of the encapsulation medium between end turns and housing larger than 0.7 W/(mK).…”

OVE Nachrichten

“…An advanced method based on CFD numerical simulations and on dimensional analysis has been developed to characterize the heat transfer on the end-windings of an electrical machine with a double air cooled system (DACS) in [29]. In Fig.…”