Oklahoma Electrical Practice Exam

To determine the line current in a 3-phase, 480 volt delta system with a balanced load, we use the formula that relates power, voltage, and current in a three-phase system:

\[

P = \sqrt{3} \times V_{line} \times I_{line}

\]

Where:

- \( P \) is the total power in watts (or VA),

- \( V_{line} \) is the line-to-line voltage,

- \( I_{line} \) is the line current.

In this case, the total load is 80,000 VA, and the line-to-line voltage for the delta system is 480 volts. Rearranging the equation to solve for the line current yields:

\[

I_{line} = \frac{P}{\sqrt{3} \times V_{line}}

\]

Substituting the known values:

\[

I_{line} = \frac{80,000}{\sqrt{3} \times 480}

\]

Calculating the term \( \sqrt{3} \approx 1.732 \), we find:

\[

I_{line} = \frac{80,000}{1.732 \times