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Created 9th September 2014 @ 14:29

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TWEEKARN\

ez-sports.ru

i need some help to solve this

S = U * I * sqrt3
S = 230 * 97.29 * sqrt3
S = 38757.6

P = S * cos Φ = U * I * sqrt3 * cos Φ
P = 38757.6 * 0.85 = 230 * 97.29 * sqrt3 * 0.85
P = ?

i use wolframalpha as my calc, but this appears http://www.wolframalpha.com/input/?i=38757.6+*+0.85+%3D+230+*+97.29+*+sqrt3+*+0.85

i will reward u with my greatest thanks if u solve it


Last edited by TWEEKARN\,

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Quoted from TWEEKARN\

i need some help to solve this

S = U * I * sqrt3
S = 230 * 97.29 * sqrt3
S = 38757.6

P = S * cos Φ = U * I * sqrt3 * cos Φ
P = 38757.6 * 0.85 = 230 * 97.29 * sqrt3 * 0.85
P = ?

i use wolframalpha as my calc, but this appears http://www.wolframalpha.com/input/?i=38757.6+*+0.85+%3D+230+*+97.29+*+sqrt3+*+0.85

i will reward u with my greatest thanks if u solve it

just put in 230 * 97.29 * sqrt3 * 0.85… (like so: http://www.wolframalpha.com/input/?i=230+*+97.29+*+sqrt3+*+0.85)

It says false because you rounded your value for S (to get some other value, let’s call it S’), then you’re trying to tell it that S’ * 0.85 = S * 0.85, which it tells you is false.

TWEEKARN\

ez-sports.ru

if u wondered about the values, here’s the task:

A three-phase motor has the following data: 230V/50Hz, 16kW, cos Φ = 0,85 og η = 0,95.

a) Calculate the necessary values ​​and create effekttrekant ( <- http://kunnskapsbasen.com/heleinnlegget.asp?il=107&kt=24&ukt=166)

here's what i've already found out:
P1 = U * I * sqrt3 * cos Φ
P1 = 230 * 97.29 * sqrt3 * 0.85
P1 = 32943.9W
I = P2 / U * sqrt3 * cos Φ * η
I = 16000 / 230 * sqrt3 * 0.85 * 0.95
I = 97.29A

and here's the 3 formulas i need for that "effect triangle"

S = U * I * sqrt3
P = S * cos Φ = U * I * sqrt3 * cos Φ
Q = S * sin Φ = U * I * sqrt3 * sin Φ

but since i can't figure out how to find P, i can't continue


Last edited by TWEEKARN\,

TWEEKARN\

ez-sports.ru

btw thanks, might think that was the solution

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