Design of Water-Cooled Calorimeter for Electric Motor's Power Loss Measurement

The paper presents the design process of and measurement possibilities with a water cooled, balanced calorimeter for the power loss measurement of an induction motor. The tested motor is a totally enclosed fan-cooled cage induction motor with efficiency of 92%. To create an optimal design, aspects of heat-leakage and measurement times are considered early in the design stage. Coupled heat and air-flow simulations with computational fluid-dynamic capabilities of the 3-D geometry of the calorimeter are carried out to verify the effectiveness of the chosen design parameters. Calorimetric measurements of the power loss of the motor at different operating points are presented, and compared with the traditional input-output method. The calorimeter achieves extended measurement accuracy of 2.08% in measurement of 2.6 kW of power loss.