A 1-horsepower, 24-volt DC motor that is 80 percent efficient requires 932.5 watts. How much power will a 1-horsepower, 12-volt DC motor that is 75 percent efficient require?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Enhance your understanding of the fundamentals of electricity with the AMT General Exam. Study with multiple-choice questions crafted to improve your knowledge and confidence. Prepare effectively for your success!

Multiple Choice

A 1-horsepower, 24-volt DC motor that is 80 percent efficient requires 932.5 watts. How much power will a 1-horsepower, 12-volt DC motor that is 75 percent efficient require?

Explanation:
The key idea is the relation between input power, output power, and efficiency: η = P_out / P_in, so P_in = P_out / η. A mechanical output of 1 horsepower equals 746 watts. If the motor is 75% efficient, it needs P_in = 746 / 0.75 ≈ 994.7 watts of electrical power to deliver that 1 HP. The voltage doesn’t change the required input power for the same mechanical output; it would only affect current drawn (I = P_in / V). So the correct amount of power required is about 994.6 watts.

The key idea is the relation between input power, output power, and efficiency: η = P_out / P_in, so P_in = P_out / η. A mechanical output of 1 horsepower equals 746 watts. If the motor is 75% efficient, it needs P_in = 746 / 0.75 ≈ 994.7 watts of electrical power to deliver that 1 HP. The voltage doesn’t change the required input power for the same mechanical output; it would only affect current drawn (I = P_in / V). So the correct amount of power required is about 994.6 watts.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy