Electrical PE Exam - Per-Unit (Base Formulas)

[@bucknelljay]

Another good one. The 'up next' doesn't show the next video in the series. Can you change this or provide a link in the description to the next video?

[@Hasoken]

there is a third formula for the 3-phase. Z_b=V_b/(sqrt(3)*I_b)

[@chadbags]

At 11:40 you show the algebra for I_phase. Strictly from algebra is seems that I_phase =[ sqrt3(P_total)/(3V_L)]. You show it as I_phase = [P_total/(sqrt3V_L)]. How? Also, are you implying that I_phase = I_base? Please explain

[@mariogregory4922]

sqrt3 * sqrt3 = 3. Hope that helps

[@Udamasta]

Now I may be only a lowly undergrad, but I believe your statement regarding the condition for usage of the 3 phase formulas is slightly flawed. If V_b was the line-to-line voltage why would we multiply it by root(3)? You state that the V_b = root(3)*V_phase. That is true. But then the denominator of your function is assuming not V_b to be a line-to-line measurement but a line-to-neutral (phase) measurement. Please correct me if I'm wrong but I believe the comment under me from 4 years ago was asserting a similar criticism.

[@kevintoo6247]

I thought the same thing, but he does derive the formula at 11:40.

[@spelunkerd]

Well explained!