# How do you calculate the complex power phase angle (φ) for reactive power calculations?

Discussion in 'Electrics UK' started by eveares, 15 Oct 2017.

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1. ### eveares

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I know you can find reactive power out from the alternative formula below, but using the formula "P(W) = V(V) × I(A) × cos φ", how do you obtain the complex power phase angle (φ) from knowing the Voltage, Power and Current?

Alternative formula: Reactive Power=√ (Apparent Power²– True power²)

3. ### JohnW2

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If you are literally asking what you have written, you can surely rearrange that equation to achieve what you ask, can't you? However, in case you I'm over-estimating you ...

cos φ = P(W) / [ V(V) × I(A)]

Kind Regards, John

4. ### eveares

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Now I feel really stupid , of course you can reverse the formula. I think I better go to the doctor and get by brain checked out!

Thanks for the obvious.

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5. ### DetlefSchmitz

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Of course the final hurdle is how to do arccos on the windows calculator. (inv cos)

6. ### JohnW2

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It might not be the final hurdle - we don't know what he plans to do with it if/when he manages to calculate it

Kind Regards, John

8. ### mwatsonxx

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I just knew it would be another of your pointless responses.

9. ### JohnW2

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... and the point of this one of yours is?

Kind Regards, John

10. ### mwatsonxx

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To point out that the majority of your responses are do not contribute anything useful.

11. ### JohnW2

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I see.

Are you perhaps talking about posts like ...

Kind Regards, John

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