Calculating power and Impedance

Thread Starter

regexp

Joined Nov 20, 2010
24
Hi,

One part of this question, i am uncertain of.

"The current and Voltage through an impedance are known"
\(u(t) = \sqrt2\cdot110cos(\omega t+85)V\)
\(i(t) = \sqrt2\cdot0.4cos(\omega t+15)A\)

Calculate the power and reactive power in the impedance.

The powerangle is 70°
So we have \(V_{rms} \cdot I_{rms} \cdot cos 70^\circ= 15A\)
and \(V_{rms} \cdot I_{rms} \cdot sin 70^\circ = 41.34VA\)

"Calculate the apparent power in the impedance"

Apparent power = \(V_{rms} \cdot I_{rms} = 44\)

"Calculate the impedance Z"

Not sure about this one, is it simply 110/0.4 = 275Ω ?
 
Last edited:

Thread Starter

regexp

Joined Nov 20, 2010
24
Second try.

Power P = \( V_{rms} \cdot I_{rms} cos(\theta)\)

Reactive power Q = \(V_{rms} \cdot I_{rms} sin(\theta)\)

Apparent power S = IE(being the same as V_rms x I_rms)?
 
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