# Three phase ac network

1. Jan 31, 2015

### JasonHathaway

Hi everyone,

1. The problem statement, all variables and given/known data

Three inductors with 0.1 H each are delta connected to three phase ac newtork with 220V/50Hz. Determine Iph, IL, P, Q and Theta.

2. Relevant equations
Showed at the attempt.

3. The attempt at a solution

XL=2*pi*f*L=31.4 ohms
Iph=Uph/XL=220/31.4=7 A
IL=1.73*7=12.12 A

Q=(Iph)^2 XL=Uph Iph sin(theta)

Since I don't have theta and I need to determine it in thte first place, I shall use he first law.
Q=(7)^2 31.4=1538.6 VAR
QT=3*Q=4615 VAR

Then, I shall substitute the value of Q in the second law to get theta.
sin^-1 (theta)=Q/Uph Iph=1538.6/220*7=87.55 ْ

P=Uph Iph cos(theta)=65.65 W
PT=3*P=196.95 W

2. Jan 31, 2015

### Staff: Mentor

Are you sure that you should be seeing real power being dissipated by a purely reactive load? You might want to reconsider what the phase angle must be for such a load.

3. Feb 6, 2015

### JasonHathaway

I found out that a purley inductor doesn't disspate any power, which leads to P=0. Thanks :)