What is the approximate efficiency of a motor with an output of 2 hp and an input of 2487 watts (1 hp equals 746 watts)?

What is the approximate efficiency of a motor with an output of 2 hp and an input of 2487 watts (1 hp equals 746 watts)?

• A. 50%
• B. 60%
• C. 70%
• D. 80%

Answer: (B)

To determine the efficiency of the motor, you first need to convert the output power from horsepower (hp) to watts. Given that 1 horsepower equals 746 watts, for a motor with an output of 2 hp, the output in watts is calculated as: 2 hp * 746 watts/hp = 1492 watts. Efficiency is defined as the ratio of output power to input power, expressed as a percentage. The formula for efficiency can be represented as: Efficiency (%) = (Output Power / Input Power) × 100. Substituting the values you've calculated: Efficiency (%) = (1492 watts / 2487 watts) × 100. Now performing the calculation: Efficiency (%) ≈ (0.5992) × 100 ≈ 59.92%. When rounded to the nearest whole number, this yields an efficiency of approximately 60%. This value matches with one of the choices, confirming that the efficiency of the motor is around 60%, which aligns with option B. Understanding the calculation of efficiency helps clarify how effectively a motor converts input energy into useful work.

To determine the efficiency of the motor, you first need to convert the output power from horsepower (hp) to watts. Given that 1 horsepower equals 746 watts, for a motor with an output of 2 hp, the output in watts is calculated as:

2 hp * 746 watts/hp = 1492 watts.

Efficiency is defined as the ratio of output power to input power, expressed as a percentage. The formula for efficiency can be represented as:

Efficiency (%) = (Output Power / Input Power) × 100.

Substituting the values you've calculated:

Efficiency (%) = (1492 watts / 2487 watts) × 100.

Now performing the calculation:

Efficiency (%) ≈ (0.5992) × 100 ≈ 59.92%.

When rounded to the nearest whole number, this yields an efficiency of approximately 60%.

This value matches with one of the choices, confirming that the efficiency of the motor is around 60%, which aligns with option B. Understanding the calculation of efficiency helps clarify how effectively a motor converts input energy into useful work.