# Reactance Power Measurement

Hi, I am studyig a project that measures reactance power and defines both inductive and capacitve reatance power. In order to do that, I am using that circuit:
http://openenergymonitor.org/emon/buildingblocks/how-to-build-an-arduino-energy-monitor

That circuit can measure both apparent and real power. Therefore I can calculate reactance power. But I need inductive and capacitve values of reactance. How can I do that?
Thanks

But I need inductive and capacitve values of reactance.

Do you mean you want to take the readings from the power meter and then calculate inductive or capacitive reactance?

I don't have the formulas off the top of my head, but that shouldn't be too hard as long as the power meter can tell you if the load is inductive or capatitive (or if can tell you if the current leads or lags the voltage).

You can get the total net impedance from apparent power and the resistance from real power. The difference between total impedance and resistance is reactance. (But, it's not the simple algebraic difference because the two impedance components are 90 degrees out-of-phase.)

DVDdoug:
Do you mean you want to take the readings from the power meter and then calculate inductive or capacitive reactance?

I don’t have the formulas off the top of my head, but that shouldn’t be too hard as long as the power meter can tell you if the load is inductive or capatitive (or if can tell you if the current leads or lags the voltage).

I can calculate total reactance power but I dont know whether it is capacitive or inductive. Is there any way to understand capacitive or inductive it is?

Is there any way to understand capacitive or inductive it is?

Do you want to determine if the load is capacitive or inductive, or are you saying you don't understand what capacitive or inductive reactance means?

The difference between real power and apparent power is the determined by the phase angle between voltage and current. In order to measure real power, you have to know the magnitude of that phase angle.
With an inductive load current will lag voltage, with a capacitive load current will lead voltage. So if you know the direction of the phase shift (positive or negative), you can determine if the load is capacitive or inductive.

In the real world, it's unusual to have a capacitive load. i.e. Motors are inductive, and transformers can present an inductive load.

DVDdoug:
With an inductive load current will lag voltage, with a capacitive load current will lead voltage.[/b] So if you know the direction of the phase shift (positive or negative), you can determine if the load is capacitive or inductive.

The problem is I dont know the direction of phase shift. I can calculate power factor but that only shows relations between apparent, real and reactance power. How can I understand whether voltage lagging or leading?