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Three Phase Transformer Current Formula:
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Three phase transformer current calculation determines the current flowing through each phase of a three-phase transformer based on its power rating (kVA) and operating voltage. This is essential for proper transformer sizing and protection.
The calculator uses the three phase transformer current formula:
Where:
Explanation: The formula converts kVA to VA (by multiplying by 1000), then divides by the product of voltage and square root of 3 to obtain the current per phase in a balanced three-phase system.
Details: Accurate current calculation is crucial for selecting appropriate circuit breakers, fuses, conductors, and ensuring the transformer operates within its rated capacity without overheating or damage.
Tips: Enter the transformer's kVA rating and the system voltage in volts. Both values must be positive numbers. The calculator will provide the current per phase in amperes.
Q1: Why is the square root of 3 used in the formula?
A: The square root of 3 (approximately 1.732) accounts for the phase relationship in three-phase systems where the voltage between lines is √3 times the phase voltage.
Q2: What's the difference between line current and phase current?
A: In a balanced three-phase system, line current equals phase current for delta connections, while for wye connections, line current equals phase current.
Q3: Can this formula be used for both delta and wye configurations?
A: Yes, this formula works for both delta and wye configurations when calculating line current based on line-to-line voltage.
Q4: What if the transformer has multiple taps?
A: Use the actual operating voltage at the specific tap setting being used for accurate current calculation.
Q5: How does power factor affect the current calculation?
A: This formula assumes unity power factor. For non-unity power factor, the actual current would be higher than calculated here.