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AC Power Formula:
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The AC Power Formula calculates the real power in an alternating current circuit. Unlike DC circuits where power is simply voltage times current, AC circuits require consideration of the phase difference between voltage and current, represented by the power factor.
The calculator uses the AC Power formula:
Where:
Explanation: The formula accounts for the phase difference between voltage and current in AC circuits. The power factor represents the efficiency of power usage in the circuit.
Details: Power factor is crucial in AC circuits as it indicates how effectively electrical power is being converted into useful work. A power factor of 1 means all power is being used effectively, while lower values indicate reactive power is present.
Tips: Enter voltage in volts, current in amperes, and power factor as a decimal between 0 and 1. All values must be positive and power factor must be between 0 and 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 = V×I) is the product of voltage and current, measured in volt-amperes (VA).
Q2: What causes low power factor?
A: Low power factor is typically caused by inductive loads like motors, transformers, and fluorescent lighting that create phase shift between voltage and current.
Q3: How can power factor be improved?
A: Power factor can be improved by adding capacitors to counteract inductive reactance, using synchronous motors, or employing power factor correction equipment.
Q4: What are typical power factor values?
A: Residential: 0.85-0.95, Industrial: 0.7-0.9, Commercial: 0.8-0.95. Utilities often charge penalties for power factors below 0.9.
Q5: Does this formula work for three-phase systems?
A: For three-phase systems, the formula becomes \( P = \sqrt{3} \times V_{L-L} \times I \times PF \) where \( V_{L-L} \) is line-to-line voltage.