A simple method for determining equivalent circuit parameters of double-cage induction motors from no-load and locked-rotor tests

This paper presents a simple method to determine equivalent circuit parameters of double-cage Induction Motors (IM). A new formula to calculate the equivalent circuit parameters of double-cage IM is proposed. The formula is very simple so as to be able to calculate by a calculator but can determine the parameters of outer- and inner-cages bars accurately. In addition it is possible to take magnetic saturation effect of closed-slot rotor into account. Since all equivalent circuit parameters of double-cage IM can be determined only from classical no-load and locked-rotor tests, the proposed method is suitable for utilizing as a standardized testing method for double-cage IMs. The validity of the proposed method is demonstrated by experimental results on two 5.5kW-200V-4P-22A-50Hz double-cage IMs; one is an IM with semi-closed-slot rotor, the other is an IM with closed-slot rotor.