Calorimetric Method to Measure Total Losses of the Induction Motor

Abstract

The advantage of the calorimetric method is possibility of loss determination irrespective of value supply frequency and of the shape of voltage pattern. The main principle of the calorimetric method is measurement of the heat produced in the machine. The heat is transferred to the surrounding by conduction, convection and radiation.

In the paper the new, based on the principle of the calorimetric method, laboratory stand for measurements of total loss of the induction motor is described. The stand is designed to test medium power encapsulated induction motors. The measurement chamber is similar to well known Thomas’ cylinder used in ordinary ventilation tests. Measurement of the temperature rise of the airflow through tunnel is made by means of the copper nets being resistance thermometers.

The measurement results of losses of the induction motors carried on by calorimetric method are close to value obtained by other methods. The calorimetric method fulfils requirements as a tool to determination of the value of motor efficiency fed from inverters.