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anderssok09
March 14, 2022, 11:27 AM
A wye-delta transformer has a turns ratio of 2:1. It has a secondary line voltage of 480 V. The secondary is connected to a wye-connected three-phase resistive load of 50 ohms in each phase. How much is the primary line current?

How would I go about solving this?

BruceG400
March 18, 2022, 08:16 PM
A wye-delta transformer has a turns ratio of 2:1. It has a secondary line voltage of 480 V. The secondary is connected to a wye-connected three-phase resistive load of 50 ohms in each phase. How much is the primary line current?

How would I go about solving this?

I would say it is 4.8 amps.
Since the questions says 50 ohm resistive load per phase, the wye connection does not matter. The amperage on primary or secondary windings would be equal across all phases with a ratio of 2:1 between primary and secondary.
480V divided by 50 ohms equals 9.6 amps on secondary. 9.6 amps divided by 2 equals 4.8 amps on primary.