# How to calculate Fundamental Input Power Factor

I am really confused with the concept of fundamental input factor. What was taught to me in class was the below formula

IPF(Input Power Factor) = IDF(Input Displacement Factor) x CDF (Current Distortion Factor)

Input Displacement Factor was defined by my instructor as the cosine of angle between the phase voltage and line current

So, I tried to apply this 2 things to this problem.

I did the same steps as given in the solution and got Vo = 531.19V and cosu = 0.967. [Here u is the overlap angle]

Now I tried applying the formula taught in the class and got wrong answer. Steps are shown below.

So, source line current (iR) leads the line voltage (vRY) by (0.5u+30). So, it will lead the phase voltage by (0.5u+60).