IN-SITU DETERMINATION OF THERMAL COEFFICIENTS FOR ELECTRICAL MACHINES

A method for determining the thermal coefficients in electrical machines based upon a new linear lumped parameter model and accurate measurement of temperature and loss densities within the machine is presented, The thermal network is reduced to a system of simultaneous equations. The equivalent thermal coefficients are determined by solving the equations using a singular value decomposition (SVD) method, Results obtained for a 4kW totally enclosed fan cooled (TEFC) induction motor are presented and compared with established data, The technique Is suitable for establishing more accurate thermal coefficients for composite materials and combinations of complex geometrical form.