A 120-V motor has mechanical power output of 3.00 hp. It is 80.0% efficient inco
ID: 1672739 • Letter: A
Question
A 120-V motor has mechanical power output of 3.00 hp. It is 80.0% efficient inconverting power that it takes in by electrical transmission intomechanical power. (a) Find the current in the motor.A
(b) Find the energy delivered to the motor by electricaltransmission in 3.20 h ofoperation.
J
(c) If the electric company charges $0.160/kWh, what does it costto run the motor for 3.20 h?
$
(a) Find the current in the motor.
A
(b) Find the energy delivered to the motor by electricaltransmission in 3.20 h ofoperation.
J
(c) If the electric company charges $0.160/kWh, what does it costto run the motor for 3.20 h?
$
Explanation / Answer
voltage V = 120 V power P = 3 hp 1 horse power = 735.5 W 3 h p = 3 * 735.5W = 2206.5 W 1) current in the motor I = P / V = 2206.5 / 120 = 18.3875 A 2) energy delivered to the motor by electrical transmissionin 3.20 h E = P t = 2206.5 * 3.2*60*60 = 25.4188 MW 3) electric company charges $0.160/kWh in 3.2 h motor delivers 25.41 MW 0.16*103*25.41 cost to run the motor for 3.2 h So thecompany charges on motor for 3.2 h is 4065.6$