0 A method for determining the equivalent circuit of a transformer consists of two tests: the open-circuit test and the short-circuit test. The open-circuit test, shown in Figure P7.50(a), is usually done by applying rated voltage to the primary side of the transformer while leaving the secondary side open. The current into the primary side is measured, as is the power dissipated. The short-circuit test, shown in Figure P7.50(b), is performed by increasing the primary voltage until rated current is going into the transformer while the secondary side is short-circuited. The current into the transformer, the applied voltage, and the power dissipated are measured. The equivalent circuit of a transformer is shown in Figure P7.50(c), where rw and Lu represent the winding resistance and inductance, respectively, and r. and Le represent the losses in the core of the transformer and the inductance of the core. The ideal transformer is also included in the model. With the open-circuit test, we may assume that Íp = Is = 0. Then all the current that is measured is directed through the parallel combination of r. and Le. We also assume that |r.|| j@Ld] is much greater than Fy +jøLµ. Using these assumptions and the open-circuit test data, we can find the resistance the inductance Lc. and In the short-circuit test, we assume that Vsacondary is zero, so that the voltage on the primary side of the ideal transformer is also zero, causing no current flow through the r- Le parallel combination. Using this assumption with the short-circuit test data, we are able to find the resistance T, and inductance Lw. Using the following test data, find the equivalent circuit of the transformer: Open-circult test: V = 241 V I = 0.95 A P = 32 W Short-circuit test: V = 5V I 5.25 A P = 26 W Both tests were made at w = 377 rad/s. Lw ww Is Vacondary ele ele ww