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
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
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