What is the expected VA rating at 5A for a current transformer with a burden designation of B0.9 per IEEE C57.13?

To determine the expected VA rating at 5A for a current transformer with a burden designation of B0.9 per IEEE C57.13, it is important to understand the definition of burden and its relation to the VA rating.

In IEEE C57.13, the burden rating is specified as a way to indicate the maximum amount of load that can be connected to the output of the current transformer without exceeding its accuracy limits. The designation B0.9 usually refers to a burden of 0.9 ohms.

The VA rating of a current transformer can be calculated using the formula:

[ \text{VA} = I^2 \times R ]

where ( I ) is the current (in amperes), and ( R ) is the burden (in ohms).

For this case, with a secondary current of 5A and a burden of 0.9 ohms:

[ \text{VA} = (5^2) \times (0.9) = 25 \times 0.9 = 22.5 ]

Thus, the expected VA rating at 5A is 22.5 VA. This aligns with the burden's designation and the output specifications for a transformer