Electrical Engineering ⇒ Topic : Equivalent Values Referred to Primary

Equivalent Values Referred to Primary

Let us transfer resistance R₂ of the secondary to primary winding. Let the referred value be R'₂ This reflected value of resistance R'₂ will produce the same heating effect in primary as R2 produces in secondary side. So it can be expressed as:

                                                      .............. (1)

where a is the turn ratio of primary to secondary and is given as:

                                                                .............. (2)

Similarly, X'₂ be the reactance of the secondary winding reflected or referred to primary side.This reflected reactance X'₂ will produce the same heating effect in primary as X₂ produces in secondary. Therefore, we can write

                  ............(3)

If R_e1, X_e1, and Z_e1 represent the effective resistance, effective reactance, and effective impedance, respectively, of the whole transformer referred to the primary, we can write