I really need help with power calculations.
Real power is the power into a resistive load.
For my application, I know the Voltage (Vrms), the Impedance (Z), and the phase angle of the impedance.
I am using the equation:
P = (V * V) / (Z * Cos(angle)) Watts
The denominator in the above equation is the resistance of the load.
The above equation is equivalent to your:
P = true power P = E*E/R
Other people are saying that the equation should be:
P = (V * V * Cos(angle) ) / Z Watts
Using numbers from your inductance & resistance page, V=120 Vrms, Z=85.078 ohms at an angle of 45.152 deg.
My equation gives the power to be: 240 Watts
The other equation gives the power to be: 119.3 Watts. The same value that you get.
So, here are my questions:
1. Why is my equation (P = (V * V) / (Z * Cos(angle))) wrong?
2. How was the other equation (P = (V * V * Cos(angle) ) / Z) derived?
I am not too familiar with these forums. If someone can answer my questions, please reply to: <SNIP>
Thanks,
Justin Daubar
Real power is the power into a resistive load.
For my application, I know the Voltage (Vrms), the Impedance (Z), and the phase angle of the impedance.
I am using the equation:
P = (V * V) / (Z * Cos(angle)) Watts
The denominator in the above equation is the resistance of the load.
The above equation is equivalent to your:
P = true power P = E*E/R
Other people are saying that the equation should be:
P = (V * V * Cos(angle) ) / Z Watts
Using numbers from your inductance & resistance page, V=120 Vrms, Z=85.078 ohms at an angle of 45.152 deg.
My equation gives the power to be: 240 Watts
The other equation gives the power to be: 119.3 Watts. The same value that you get.
So, here are my questions:
1. Why is my equation (P = (V * V) / (Z * Cos(angle))) wrong?
2. How was the other equation (P = (V * V * Cos(angle) ) / Z) derived?
I am not too familiar with these forums. If someone can answer my questions, please reply to: <SNIP>
Thanks,
Justin Daubar
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