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AC Power Formula:
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AC power calculation determines the real power consumed in an alternating current circuit. Unlike DC circuits, AC power depends on both magnitude and phase relationship between voltage and current, represented by the power factor.
The calculator uses the AC power formula:
Where:
Explanation: The formula calculates the actual power consumed by a load in an AC circuit, accounting for the phase difference between voltage and current.
Details: Power factor represents the efficiency of power usage. A power factor of 1 indicates all power is used for useful work, while lower values indicate reactive power consumption that doesn't perform useful work but still requires infrastructure capacity.
Tips: Enter RMS voltage in volts, RMS current in amperes, and power factor (between 0 and 1). All values must be positive with power factor in the valid range.
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 = V×I) is the product of RMS voltage and current measured in volt-amperes (VA).
Q2: Why is power factor important in electrical systems?
A: Low power factor increases current for the same real power, requiring larger conductors, transformers, and generating capacity. Utilities often charge penalties for low power factor.
Q3: What are typical power factor values?
A: Resistive loads have PF=1, motors 0.8-0.9, fluorescent lights 0.5-0.9. Industrial facilities aim for 0.95 or higher to avoid penalties.
Q4: How can power factor be improved?
A: Power factor correction capacitors, synchronous condensers, or active power factor correction circuits can improve power factor by compensating for reactive power.
Q5: Does this formula work for three-phase systems?
A: For balanced three-phase systems, multiply by √3: P = √3 × V × I × cos φ, where V is line-to-line voltage.