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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 voltage/current magnitude and the phase relationship between them, represented by the power factor.
The calculator uses the AC power formula:
Where:
Explanation: The formula calculates the actual power consumed by the load, accounting for the phase difference between voltage and current in AC circuits.
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 that doesn't perform useful work but still requires infrastructure capacity.
Tips: Enter voltage in volts, current in amps, and power factor as a decimal between 0 and 1. All values must be positive, with power factor 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 VA, and includes both real and reactive power.
Q2: What causes low power factor?
A: Inductive loads like motors, transformers, and fluorescent lighting cause current to lag voltage, resulting in lower power factor. Capacitive loads can cause leading power factor.
Q3: How can power factor be improved?
A: Power factor correction capacitors can be added to counteract inductive loads, bringing the power factor closer to 1 and reducing reactive power.
Q4: What are typical power factor values?
A: Residential: 0.85-0.95, Industrial: 0.7-0.9, Pure resistive load: 1.0. Utilities often charge penalties for power factors below 0.9.
Q5: Does this formula work for three-phase systems?
A: For balanced three-phase systems, multiply by √3: P = √3 × V × I × cosφ, where V is line-to-line voltage and I is line current.