Limited Licensed Electrician (LLE) Practice Test 2026 - Free Electrician Exam Questions and Study Guide

To determine the full-load current of a 460 volt, 20 horsepower (hp) motor, you can use the formula that relates horsepower to current for three-phase motors. The formula is:

\[ I = \frac{P \times 746}{\sqrt{3} \times V \times \text{efficiency}} \]

Where:

- \( I \) is the full-load current in amperes

- \( P \) is the horsepower (20 hp, in this case)

- 746 is the number of watts per horsepower

- \( V \) is the line voltage (460 V)

- Efficiency is typically around 0.9 (90%) for a well-functioning motor but can vary.

Assuming an efficiency of about 0.9, the calculation would look like this:

1. Convert horsepower to watts: \( 20 \times 746 = 14920 \) watts.

2. Plug the values into the formula:

\[ I = \frac{14920}{\sqrt{3} \times 460 \times 0.9} \]

Calculating \( \sqrt{3} \) gives approximately 1.732, and then:

\[ I \approx \frac