Test Analysis for Equivalent Circuit Parameters of Precision Induction Motors

The equivalent circuit of the induction motor has been modified by placing the iron loss resistance branch between r1 and x1 instead of in parallel with xM. By use of this circuit, the open circuit and stalled rotor tests are analyzed for the circuit parameters. The method given shows an improvement in obtaining X independently of r2 and in obtaining r2 itself. These improvements allow successful analyses at higher values of (r2/s)/X02 than previously. An improved method is shown for cases when x1 ¿ x2. It is shown that the relationship (X01 - Q) - P is significant in determining whether (r2/s)/X02 is above or below 1.00. A useful validity check on the test results is given. An alternate approximate method is given for cases of high values of (r2/s)/X02. A calculation sheet or test analysis format is given.