Abstract
This paper presents methods to determine the operational impedance of rotating machines by Fourier Transformation of the voltage and current measured when a step (or pulse) voltage is applied to the two stator winding terminals. These standstill tests using a small-capacity DC power supply unit are tentatively named the DC Testing Method. We also describe in detail the case using a DC power source with ripple and the case in which a step (or pulse) voltage is applied with current flowing. These methods are applied to a 5.5kW squirrel-cage induction motor having semi-closed rotor slots. The validity of the proposed prediction methods is demonstrated by comparing the calculated and measured speed characteristics of the tested induction machine.
