Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculate the power of a the lift motor

  1. May 20, 2011 #1
    Please help :

    Calculate the power of a the lift motor,when is lift on a distance on a building site lift 400kg of brick50m to the top of a buiding in 24 seconds

    Ans ?

    Regards.
    taomay
     
  2. jcsd
  3. May 20, 2011 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    2015 Award

    You tell us.
     
  4. May 20, 2011 #3

    Ans :

    mass= 400kg (convert mass to weight 1kg=9.81N (force of gravity on 1kg)

    400x9.81=3924N
    Workdone (j)= force xdistance
    3924x50 =196200

    Power = 196200 /24= 8175 W
    convert to KW =8.175KW
     
  5. Sep 4, 2012 #4
    Assuming that this is a cable driven lift and not a hydraulic lift, more data is required to calculate the HP required to lift the load:
    Desired speed of lift
    % of counterweighting
    Hoisting machine eff.
    acceleration rate and rate of change of acceleration rate (known as jerk rate)
    Hoistway eff.
    H.P. required = Speed (fpm) x capacity (lbs) x Percentage of uncounterweighted load (usually .4 to .5 / 33000) / overall eff.*
    * this can actually range anywhere from 40% to 90% depending upon machine be geared or gearless, the roping type usually being 1:1 or 2:1 as well as the types of guide shoes (roller or slide).
    If steep accelleration and jerk rates are required to meet a specific performance than a larger motor maybe required to meet those peak torque requirements.
    To convert HP to KW, multiply the HP times .746
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Calculate the power of a the lift motor
  1. PH Calculation (Replies: 1)

  2. Enthalpy calculation (Replies: 1)

  3. Calculating molality (Replies: 1)

Loading...