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3-Phase Transformer Current Equation:
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The full load current of a 3-phase transformer represents the current flowing through each phase when the transformer is operating at its rated power. It's crucial for sizing protection devices and conductors.
The calculator uses the 3-phase current equation:
Where:
Explanation: The equation accounts for the phase relationship in 3-phase systems and the power factor which represents the ratio of real power to apparent power.
Details: Accurate current calculation is essential for proper transformer sizing, circuit breaker selection, conductor sizing, and overall electrical system design.
Tips: Enter power in watts, line voltage in volts, and power factor (typically between 0.8 and 1). All values must be positive numbers.
Q1: What's the difference between line and phase voltage?
A: In 3-phase systems, line voltage is between any two lines, while phase voltage is between any line and neutral. For delta connections, they're equal; for wye, line voltage is √3 times phase voltage.
Q2: What is a typical power factor value?
A: For transformers, power factor typically ranges from 0.8 to 0.95. The exact value depends on the load characteristics.
Q3: How does this differ from single-phase current calculation?
A: Single-phase uses I = P/(V×PF) without the √3 factor. Three-phase accounts for the phase displacement between the three conductors.
Q4: Why is full load current important?
A: It determines the maximum current the transformer can handle continuously without overheating or damage.
Q5: Can this be used for motor current calculation?
A: Similar principles apply, but motors have additional factors like efficiency that should be considered in the calculation.