For a 3P DELTA Transformer, how is the line current (IL) related to the primary current (IP)?

In a 3P DELTA transformer configuration, the relationship between the line current (IL) and the primary current (IP) is fundamentally connected to the nature of the delta connection. In a delta configuration, the line current is greater than the phase current by a factor of the square root of three (approximately 1.732).

In a three-phase system, the current flows in three conductors, and each phase sees the same current. However, because the currents in each phase are out of phase with each other, the total line current is derived from the vector sum of the phase currents. Specifically, the phase current (IP) in each winding will contribute to the overall line current (IL) as such:

IL = IP x √3

Thus, for a delta transformer, the line current is indeed equal to the phase current multiplied by the square root of three, which corresponds to the correct answer. This relationship is essential for understanding how power is distributed in three-phase systems, as it underscores how current behaves differently in various transformer configurations. The other provided choices do not accurately reflect this relationship as they pertain to different calculations or configurations.