A Simple Method to Determine Double-Cage Rotor Equivalent Circuit Parameters of Induction Motors From No-Load and Locked-Rotor Tests

This paper presents a simple method to determine double-cage rotor equivalent circuit parameters of induction motors (IMs). A new formula to calculate the double-cage rotor equivalent circuit parameters is proposed. The formula is sufficiently simple to be calculated by a calculator but can determine the parameters of outer- and inner-cage conductors. The proposed method takes the magnetic saturation effect of a closed-slot rotor into account and applies to not only double-cage but also single-cage IMs. All equivalent circuit parameters can be determined using only classical no-load and locked-rotor tests. Thus, the proposed method is suitable to be used as a standardized testing method for IMs. The validity of the proposed method is demonstrated by experimental results on four 5.5 kW-200 V-4 P-22 A-50 Hz IMs: double- and single-cage IMs with semi-closed- and closed-slot rotors.