Calculate the power of a the lift motor


by taomay
Tags: lift, motor, power
taomay
taomay is offline
#1
May20-11, 08:53 AM
P: 2
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
Phys.Org News Partner Science news on Phys.org
NASA's space station Robonaut finally getting legs
Free the seed: OSSI nurtures growing plants without patent barriers
Going nuts? Turkey looks to pistachios to heat new eco-city
SteamKing
SteamKing is offline
#2
May20-11, 09:11 AM
HW Helper
Thanks
P: 5,548
You tell us.
taomay
taomay is offline
#3
May20-11, 02:38 PM
P: 2
Quote Quote by taomay View Post
Please help :

Calculate the power of a the lift motor,when is lift on a distance on a building site lift 400kg of brick 50m 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

shadow123
shadow123 is offline
#4
Sep4-12, 02:49 PM
P: 1

Calculate the power of a the lift motor


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


Register to reply

Related Discussions
Motor torque calculation for lift having chain drive Engineering Systems & Design 1
how to calculate the motor power Electrical Engineering 0
How to calculate Lift force ? Aerospace Engineering 3
Motor selection for vertical lift door with balanced counterweights Mechanical Engineering 1
how to calculate lift for delta wing Mechanical Engineering 10