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Power factor correction allows you to calculate apparent power, true power, reactive power and your phase angle.^{[1] X Research source } Consider the equation of a right triangle. So to calculate the angle you need to know your Cosine, Sine and Tangent laws. You also will need to know The Pythagorean Theorem ( c² = a² + b² ) for calculating the magnitudes of the sides of the triangle. You will also need to know what units each type of power is in. Apparent power is measured in VoltAmps. True power is measured in Watts and your Reactive power is measured in the units called VoltAmpReactive (VAR’s). There are several equations to calculate these and all will be covered in the article. You now have the basis of what you are trying to calculate.
Steps

1Calculate impedance. (Pretend as if impedance was in the same place as apparent power in the picture above). So to find impedance you need to use the Pythagorean Theorem c = √ (a² + b²).^{[2] X Research source }

2Therefore Impedance Total (represented as “Z”) is equal to Real Power squared plus Reactive power squared and then take the square root of the answer.
 ( Z = √(60² + 60²) ). So if you enter that into your scientific calculator you will receive an answer of 84.85Ω. ( Z = 84.85Ω )
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3Find your phase angle. So you now have your hypotenuse which is your impedance. You also have your adjacent side which is your true power and you have your opposite side which is your reactive power. So to find the angle you can use any the laws stated earlier. For example we use the Tangent Law which is the opposite side divided by the adjacent side (Reactive/True).^{[3] X Research source }
 You should have an equation that looks like this: (60/60 = 1)

4Take the inverse of the tangent and acquire your Phase Angle. The inverse tangent is a button on your calculator. So you now take the inverse tangent of the equation in the previous step and this will give you your phase angle. Your equation should look something like this: tan ‾ ¹ (1) = Phase Angle. So your answer should be 45°.

5Calculate your total Current (Amps). Your current is in the units of amps also represented as an “A”. The formula used for calculating current is Voltage divided by Impedance which numerically looks like this: 120V/84.85Ω. You should now have an answer around 1.414A. ( 120V/84.85Ω = 1.414A )

6You must now calculate your apparent power which is represented as “S”. To calculate apparent power you do not need to use the Pythagorean Theorem because your hypotenuse was considered your impedance. Remembering that apparent power is in the units of VoltAmps we can calculate apparent power using the formula: Voltage squared divided by your total impedance.^{[4] X Research source } Your equation should look like this: 120V²/84.85Ω. You should now get an answer of 169.71VA. ( 120²/84.85 = 169.71 )

7You must now calculate your true power which is represented as “P”. To calculate true power you must have found current which you did in step number four. True power which is in the units of a Watt is calculated by multiplying your current squared (1.414²) by the resistance (60Ω) in your circuit. Your equation should look like this: 1.414² x 60 = 119.96 W.

8Calculate your Power Factor! To calculate your power factor you need the following information: Watts and VoltAmps.^{[5] X Research source } You have calculated this information in the previous steps. Your wattage is equal to 119.96W and your VoltAmps are equal to 169.71VA. The formula for your power factor, also represented as Pf, is Watts divided by VoltAmps. You should have an equation that looks something like this: 119.96W/169.71VA = 0.71Pf
 This can also be expressed as a percentage therefore you multiply 0.71 by 100 giving you a power factor of 71%.^{[6] X Research source }
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Community Q&A

QuestionWhat is the reason for calculating the power factor?Community AnswerThe power factor is calculated to reduce loading on the source and the physical requirements of the conductors that carry that current. By calculating the power factor, you determine how inefficient your circuit is. This gives you the information you need to make it more efficient by adding in components that will yield power factor correction.

QuestionHow do I find out how much power my lamp needs?Community AnswerYou can get an ammeter and voltmeter and attach them to the lamp wires. If you don't want to do that much work, you can read the instructions in the lamp's package.

QuestionHow can I increase a power factor?Community AnswerIf the circuit is inductive, by adding in a cap bank. If the circuit is capacitive, by adding in inductive loads.

QuestionHow do I improve power factor?Community AnswerBy use of high power factor motors, induction motors with phase advancers, and static capacitors.

QuestionCan you clarify step four?Community AnswerIn step four, the user has a right triangle. In the case of a right triangle, the tangent of the angle theta is the opposite (reactive power) divided by the adjacent (real power). Taking the inverse tangent of this ratio gives you the angle (make sure your calculator is in degrees). This angle is the phase difference between your voltage and current.

QuestionHow do I get the resistance?Community AnswerThe resistance is calculated from the real component of the power triangle (a value in watts) and your knowledge of the voltage. R = V^2 / P. R is in ohms, V is in volts and P is in watts.

QuestionIf the voltage is 120V, the power is 230W, and the power factor is 0.23, then what is the current?Jim CoombesCommunity AnswerPF = P/S which means S=P/PF. S = 230/0.23 = 1000 VA. P = IE which means I = P/E = 1000/120 = 8.33 A.

QuestionHow do you calculate the required capacitance to increase a low power factor?Jim CoombesCommunity AnswerYou need to know the source voltage and frequency, reactive power, real power and power factor goal (for example, 0.93) of the circuit in question then you need to calculate the following: Apparent Power (S) = real power (W) / PF goal. Total Reactive Power (QT) = sqrt(real power ^ 2 apparent power ^ 2. Capacitive Reactive Power (QC) = total reactive power  inductive reactive power. Capactive Reactance (XC) = source voltage ^ 2 / Capacitive Reactive Power. Capacitance (C) = 1 / (2 *pi * frequency * Capacitive Reactance). From this you will have to find the next higher standard capacitor to install.

QuestionHow do I find a power factor calculator? Is one available?Community AnswerThere are many available online. Google "power factor calculator."
Tips
Warnings
 When calculating your impedance you use the inverse tangent function and not just the regular tangent function on your calculator. This will give you an incorrect phase angle.Thanks!
 This was just a very basic example of how to calculate a phase angle and power factor. There is much more complicated circuits including capacitive power and higher resistances and reactance.Thanks!
Things You'll Need
 scientific calculator
 a pencil
 eraser
 a sheet of paper
References
 ↑ https://www.allaboutcircuits.com/textbook/alternatingcurrent/chpt11/practicalpowerfactorcorrection/
 ↑ https://www.ndeed.org/GeneralResources/Formula/ECFormula/Impedance/ECImpedance.htm
 ↑ https://www.allaboutcircuits.com/textbook/alternatingcurrent/chpt11/calculatingpowerfactor/
 ↑ https://www.allaboutcircuits.com/textbook/alternatingcurrent/chpt11/truereactiveandapparentpower/
 ↑ https://www.allaboutcircuits.com/textbook/alternatingcurrent/chpt11/calculatingpowerfactor/
 ↑ https://www.electronicstutorials.ws/accircuits/powertriangle.html
About This Article
To calculate Power Factor correction, first use the Pythagorean Theorem to find the Impedance from the Real Power and the Reactive Power. The Impedance is the hypotenuse of the triangle, the adjacent side is the True Power, and the opposite side is the Reactive Power. Use a formula like the Tangent Law to find the Phase Angle, then calculate the total Current in Amps by dividing the Voltage by the Impedance. Calculate the apparent power, or Voltage Squared divided by Impedance, as well as True Power, by multiplying Current squared by the resistance in your circuit. The Power Factor is Watts divided by VoltAmps. Keep reading to see examples of these calculations!