Development of a High-Precision Calorimeter for Measuring Power Loss in Electrical Machines

This paper is concerned with the development of a high-precision 30-kW (40-hp) calorimeter and is specifically focused on how experimental errors resulting from calorimeter design and operating procedures are eliminated or mitigated. A complete calibration for the calorimetric system using a DC heater is conducted, and two induction motors rated at 5.5 and 30 kW (7 and 40 hp, respectively) are carefully tested both within and outside of the calorimeter. Loss segregation is in accordance with the IEEE 112 method B. Experimental results for the comparison of calorimetric and input-output methods clearly confirm the effectiveness of the calorimeter in terms of accurate power loss measurement. The accuracy of the calorimeter is approximately 5.6 W in the measurement of power loss of up to 4.5 kW with a resolution of 0.1 W.