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AC Power Formula:
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AC circuit power refers to the real power consumed in an alternating current circuit. Unlike DC circuits, AC power calculation must account for the phase difference between voltage and current, represented by the power factor (cos φ).
The calculator uses the AC power formula:
Where:
Explanation: The power factor represents the cosine of the phase angle between voltage and current waveforms, indicating how effectively electrical power is being converted into useful work.
Details: Power factor is crucial in AC systems as it affects the efficiency of power transmission and utilization. A low power factor results in higher current for the same real power, increasing energy losses and requiring larger conductors.
Tips: Enter voltage in volts, current in amperes, and power factor as a decimal between 0 and 1. All values must be positive, with power factor ranging from 0 to 1 inclusive.
Q1: What is the difference between real power and apparent power?
A: Real power (P) is the actual power consumed and measured in watts. Apparent power (S) is the product of voltage and current (V×I) measured in volt-amperes (VA).
Q2: What is a good power factor value?
A: Ideally, power factor should be close to 1.0. Values below 0.9 are generally considered poor and may incur penalties from utility companies in industrial settings.
Q3: How can power factor be improved?
A: Power factor can be improved by adding capacitors (power factor correction), using synchronous motors, or reducing inductive loads in the system.
Q4: When is power factor equal to 1?
A: Power factor equals 1 when the voltage and current are perfectly in phase, which occurs in purely resistive circuits.
Q5: Does this formula work for three-phase systems?
A: For balanced three-phase systems, multiply the result by √3. The formula becomes: P = √3 × V × I × cos φ, where V is line-to-line voltage.