What is the full-load current of a 460 volt, 20 hp motor?

What is the full-load current of a 460 volt, 20 hp motor?

• A. 29 amps
• B. 27 amps
• C. 31 amps
• D. 25 amps

Answer: (B)

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

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