What is the full-load current rating of a 300kVA, three-phase transformer operating at 480v?

To determine the full-load current rating of a 300kVA, three-phase transformer operating at 480V, one can use the formula:

[ I = \frac{ kVA \times 1000 }{ \sqrt{3} \times V} ]

Where:

• ( I ) is the current in amperes,

• ( kVA ) is the power rating of the transformer,

• ( V ) is the voltage.

For a 300kVA transformer at 480V, the calculation would be:

[ I = \frac{ 300 \times 1000 }{ \sqrt{3} \times 480} ]

Calculating the value:

• First, calculate ( 300 \times 1000 = 300000 ).

• Next, compute ( \sqrt{3} ) which is approximately 1.732.

• Then, compute ( \sqrt{3} \times 480 ), which is approximately 829.4.

Now divide:

[ I = \frac{300000}{829.4} \approx 361.0A ]

Rounding off yields a full-load current rating of approximately 361A. This calculation shows the importance of understanding