The important characteristics of induction motors are a torque-speed characteristic and current-speed characteristic. There are many methods to evaluate these characteristics such as measured output_ acceleration, input, and direct measurement [I]. The problems are presented in many methods. Firstly, measured output method and direct measurement method, these two methods cannot give the characteristics in all range of speed and need the constant speed when capture the data, so the temperature rise in motor will affect the data. Second, the input method, the stator losses of motor cannot readily determined during'operating condition; therefore, the result must he approximated.