Both subject problems want you to find the amount of capacitance required to raise the existing power factor to some improved value. Graffeo wants to raise it to .90, while Camara wants to raise it to unity.
Both problems are setup similarly, and both P.E.'s use the same procedure, but they diverge when they arrive at their respective solutions.
Graffeo seems to interpret the "capacitance required" as the total 3PH capacitance, which I concur with. On the other hand, Camara interprets the "capacitance required" as capacitance per phase, so he divides the required Volt-Amps by three and completes his solution, which is precisely 1/3 of the total capacitance. It should be noted that Camara does not ask for capacitance per phase; he simply asks, "What is most nearly the capacitance required to correct the power factor?"
It should be noted that Ugly's power factor correction table solves for total VARs, not VARs/PH.
So, if I see a problem like this on the Exam, I'm inclined to provide an answer of TOTAL capacitance/VAR instead of capacitance/VAR per phase, unless specifically asked for the value per phase.
Do you think this is the right approach? Do you think Camara or Graffeo is right? I'm kind of imagining that a problem like this will be asked and both answers will be given as choices.
In Camara's possible solutions, he provides both the Capacitance per phase (choice B) and the total Capacitance (choice C).
Both problems are setup similarly, and both P.E.'s use the same procedure, but they diverge when they arrive at their respective solutions.
Graffeo seems to interpret the "capacitance required" as the total 3PH capacitance, which I concur with. On the other hand, Camara interprets the "capacitance required" as capacitance per phase, so he divides the required Volt-Amps by three and completes his solution, which is precisely 1/3 of the total capacitance. It should be noted that Camara does not ask for capacitance per phase; he simply asks, "What is most nearly the capacitance required to correct the power factor?"
It should be noted that Ugly's power factor correction table solves for total VARs, not VARs/PH.
So, if I see a problem like this on the Exam, I'm inclined to provide an answer of TOTAL capacitance/VAR instead of capacitance/VAR per phase, unless specifically asked for the value per phase.
Do you think this is the right approach? Do you think Camara or Graffeo is right? I'm kind of imagining that a problem like this will be asked and both answers will be given as choices.
In Camara's possible solutions, he provides both the Capacitance per phase (choice B) and the total Capacitance (choice C).
