What is the full-load current rating of a 225kVA, three-phase transformer operating at 240V?

Prepare for NCCER's Electrical Level 3 Module 5 Test. Utilize flashcards and multiple-choice questions, each with hints and explanations. Get ready for success!

To determine the full-load current rating of a 225 kVA, three-phase transformer operating at 240V, you apply the formula for calculating the full-load current in a three-phase system, which is:

[ \text{Full-load current} (I) = \frac{\text{kVA} \times 1000}{\sqrt{3} \times \text{Voltage (V)}} ]

In this case, the kVA rating of the transformer is 225, and the operating voltage is 240V. Plugging in the values, the calculation becomes:

[ I = \frac{225 \times 1000}{\sqrt{3} \times 240} ]

Calculating the square root of 3 gives approximately 1.732, so we follow through with the calculation:

[ I = \frac{225000}{1.732 \times 240} ]

Calculating the denominator:

[ 1.732 \times 240 = 415.68 ]

Therefore:

[ I = \frac{225000}{415.68} ]

Solving this results in:

[ I \approx 541.82 \text{A} ]

Rounding this to the nearest whole

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