Measurement of Detailed Efficiency Maps Minimizing Temperature Drifts

Measurements of motor efficiency maps are an important aspect in the determination of motor characteristics. However, standardized efficiency classes are based on the losses of only one load point. An extension to efficiency maps is difficult due to transient effects like temperature drift during measurement. The scale of temperature change depends on aspects like measurement time and transient processes, which can vary between different measurements and thus may cause poor reproducibility. This chapter presents a new method that compensates this behavior without the need of control. By introducing compensation points, the average losses remain constant and therefore the temperature does too. Simulations with a detailed motor model as well as measurements on a test bench confirm this theory and show that measuring high-resolution efficiency maps with hardly any deviation from rated temperature is possible.