1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Rotational Kinetic energy to Electrical energy

  1. Oct 23, 2008 #1
    1. The problem statement, all variables and given/known data
    I have a motor with WK^2 = 4 lb-ft turning at 5400 RPM (3 * base speed) and I want to slow it to 1530 RPM (.85 * base speed). The motor is a 25HP 4 pole with a base speed of 1800 RPM.

    How much electrical energy must I absorb?

    2. Relevant equations

    3. The attempt at a solution
    I have calculated the kinetic energy of the motor @ 5400 RPM and 1530 RPM using
    Ke = 1/2 * Inertia * omega^2 and found the total Rotational energy lost. For Ke @ 5400 RPM I have calculated 3067 J and @1530 RPM I have calculated 869 J for a difference of 2197 J.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted