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 x_M. 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 r 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.