An Interactive Software for the Analysis of Thermal Characteristics of Capacitor-Run Single-Phase Induction Motors

Abstract

This paper reports on the development of a software package, in FORTRAN 90, for determination of thermal characteristics of a capacitor-run single-phase induction motor. The software can be used for (i) calculating the steady-state temperature of the body and any internal part of the motor structure, (ii) heating and cooling curves at no load, and (iii) transient thermal characteristics for surface and stator slot temperatures at different loading. For normal motor operation, the steady-state temperature rise can be used as a direct measure of loss rather than the small difference between input and output power. In the software, the design details of the motor have been used as the input data, and a mixed-parameter thermal model has been developed based on dimensional information and constant thermal coeffi cients. The thermal model developed by the authors has been tested with a 3.5-HP, 400-V, 50-Hz capacitor run totally enclosed fan cooled (TEFC) single-phase motor. Its performance has been found to be in conformity with experimental temperature data for the body and the conductors inside the slot of the motor, obtained by varying the load for different values of the run capacitance. A computer-aided data acquisition system has also been developed for the on-line temperature monitoring of the stator slot. The conductor temperature also has been estimated by resistance method.