Questions tagged [reactive-power]
Reactive power (measured in vars) is present in a system containing reactive (inductive or capacitive) components and can be either produced or consumed by different load/generation elements. Though "imaginary", the reactive power has great physical significance and is essential to the operation of the electrical system as a whole.
118 questions
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Clarifying the roles of Reactive Power and the AC Power Term in LCR Circuits
In an LCR circuit under sinusoidal AC excitation that isn't at resonance, I'm trying to clearly distinguish between: Reactive Power (Q): Defined as \$Vrms\cdot Irms\cdot sin(\phi)\$, measured in VAR. ...
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How to calculate transistor thermal dissipation in a Class B op-amp driven push-pull amplifier with reactive load?
I’ve designed a Class B Push-Pull amplifier that uses op-amp feedback and is powered by a symmetric DC supply of ±Vbat. A sinusoidal signal, V₀·sin(ωt), is applied to the non-inverting input of the ...
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What size capacitor would be appropriate to put in parallel with a 240/240 volt isolation transformer, 37.5 kW to offset the inductance?
I'm installing a 37.5 kW isolation transformer, 240V/240V with the secondary consisting of two 120V coils that I can tie together to get 240V as well as having a neutral. I am considering installing ...
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Power supply reactive power sign convection
Suppose I have a circuit like this: And I want to find the real and reactive power needed from the supply. So let Z = 10 + 10j ohms Apparent power S = V^2/Z = 5 - 5j VA Therefore real power needed is ...
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3 answers
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Can reactive power formula be derived like the active power?
In case of sinusoidal voltage and current, we get the active power \$V_{rms}I_{rms}cos(\theta_i - \theta_v)\$ by finding out the average of the multiplication of the voltage and current waveforms over ...
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4 answers
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Why is it said that inductor absorbs reactive power and capacitor delivers reactive power?
It is said that reactive power is that power that oscillates between the source and the load. The reactive power stored by an inductor or capacitor is supplied back to the source by it. So, since both ...
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2 answers
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Complex Power Conservation or "Boucherot's Theorem" - a proof without Nodal Analysis
Brief Question I'm trying to figure out a proof for the Complex Power Conservation Theorem, which does not use Nodal Analysis. Theory I know In my university this theorem has ben taught with the name &...
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1 answer
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Why does my variac have only 60 mA of magnetization current?
I bought a 3 kVA variac (230 V in, 0-300 V out, 10 A max). I made some tests, including a load test (it seems to withstand the advertised 10 A without overheating), energy efficiency test (over 97% at ...
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What is the reactive power of a capacitive circuit?
I want to understand the reactive power in a purely capacitive load. Surprisingly, I couldn't find the formula for this anywhere, so I derived it myself, and would like to ask 1. Is this formula ...
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2 answers
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How do ideal inductors dissipate high frequency noise?
I'm confused about the behavior of ideal inductors. As I understand, inductors provide a high impedance towards high frequency signals, which greatly reduces the noise. How is the reactive energy lost?...
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2 answers
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Reactive power calculation: what did I do wrong?
I calculated the question and I did not get the same answer as in the book. Could someone please explain why my method is not correct? Question: My solution: Book solution: The problem is from the ...
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3 answers
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Can reactive power be explained with phase shift?
I have learned about the phase shift between voltage and current which occurs in circuits with capacitors. For inductors I don't understand yet why phase shift occurs. I have further learned that ...
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1 answer
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Balancing inductive and capacitative phase shift
The following statements are results of my research: If a circuit contains an inductor or capacitor there is reactive power. The vector product of reactive power and actual power is the apparent power....
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1 answer
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Why do inductors and capacitors cause phase shifts between current and voltage? [closed]
I am learning about grid level stabilization services. My native language is German and I am translating the specific terminology. If I use the English terms incorrectly please edit my below sentences....
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1 answer
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Can reactive current in an AC circuit dissipate through another resistive load which is connected parallel in same circuit?
Two loads are connected in parallel to an AC circuit, one is inductive and the other is purely resistive. As per the nature of an inductive load, it will return the reactive power at end of each half ...
