LADWP Electrical Craft Helper Practice Test

To calculate the power per phase at a voltage of 480 volts, a current of 50 amperes, and a power factor of 75%, you can use the formula for real power in a three-phase system:

Real Power (P) = √3 × Voltage (V) × Current (I) × Power Factor (PF).

First, you should convert the voltage and current into the appropriate units. In this case, since you are dealing with a three-phase system, the voltage is already at the correct level (480 volts), and the current is also specified as 50 amperes.

Now, plug the values into the formula:

1. Multiply the line voltage (480 volts) by the line current (50 amperes) and the power factor (0.75):

- V × I = 480 × 50 = 24,000 volt-amperes (VA).

2. Now, multiply this result by √3 (approximately 1.732) to account for the three-phase system:

- √3 × 24,000 = 41,569.2 volt-amperes.

3. Finally, apply the power factor (0.75):

- P = 41,569.2