I am currently working my way through a book called Electrical Installation Calculations Advanced 7th edition and have reached the following question
The current in a single phase circuit lags behind the voltage by 60 degrees. The power in the circuit is 3600w and the voltage is 240v. Calculate the value in ohms of the resistance ,the reactance and the impedance.
I have calculated
VA=3600 so 3600/240=I so I = 15amps. V=IR so 240/15 = Z Z = 16 ohms
cosine phi of the angle 60 = 0.5
0.5= R/Z which is 0.5 = R/16 or 0.5 * 16 = R R = 8 ohms
Using Pythagoras Z squared = R squared + X squared or 256 64 = X squared X = 13.86 ohms
The answers in the book are given as
Resistance R = 4 ohm
Reactance X = 6.928 ohm
Impedance Z = 8 ohm
Where am I going wrong.
(all help much appreciated)
The current in a single phase circuit lags behind the voltage by 60 degrees. The power in the circuit is 3600w and the voltage is 240v. Calculate the value in ohms of the resistance ,the reactance and the impedance.
I have calculated
VA=3600 so 3600/240=I so I = 15amps. V=IR so 240/15 = Z Z = 16 ohms
cosine phi of the angle 60 = 0.5
0.5= R/Z which is 0.5 = R/16 or 0.5 * 16 = R R = 8 ohms
Using Pythagoras Z squared = R squared + X squared or 256 64 = X squared X = 13.86 ohms
The answers in the book are given as
Resistance R = 4 ohm
Reactance X = 6.928 ohm
Impedance Z = 8 ohm
Where am I going wrong.
(all help much appreciated)