Results 1 to 2 of 2

Thread: fundamental calculations - explanation

  1. #1
    Associate Engineer
    Join Date
    May 2016

    fundamental calculations - explanation

    that's my first post here.

    First of all – I do not want to ask someone to calculate something for me.
    I did my best (I hope correctly) – can you briefly check it and answer my additional questions? I am especially interested in these questions – I always have some doubts during calculations.
    Ok, so I need to roughly calculate carousel storage motor parameters.
    I am assuming that only 5 of boxes on one side will be loaded with 200 kg. This is the worst case.
    Imagine I want to lift the lowest one up to 6 meters in let’s say 30 seconds.
    W= mgh= (5*200 kg) * 10 m/s^2 * 6 m = 60000J = 60 kJ
    P= W/t = 60000 J/30 s = 2000 W = 2 kW <- required motor power

    1) There is a gear in my sketch – does this gear has any influence to formulas for power used above?
    2) By the way – if all boxes will be loaded to max can it be calculated like a lift with counterweight?
    Can anyone provide more information about “counterweight effect” which “helps” motor?
    Now let’s calculate a torque_motor and speed – it seems that tutorial example is the same:
    torque_motor / radius_1 = torque_2 / radius_2
    torque_2 / radius_2 = weight -> torque_2 = weight * radius_2
    torque_motor / radius_1 = (weight * radius_2) / radius_2 -> torque_motor = weight * radius_1
    so torque_motor = 10000N * 0,5m (more or less) = 5000 Nm
    3) This is a minimum of course – how much additional percentage do you suggest to add considering belt efficiency etc.?
    speed (0,2m/sec)
    rps_motor * radius_1 = rps_gear_2 * radius_2
    rps_gear2 * 2 * pi * radius_2 = velocity_weight -> rps_gear2 = velocity_weight / (2 * pi * radius_2)
    rps_motor = ((velocity_weight / (2 * pi * radius_2)) * radius_2) / radius_1
    rps_motor = velocity_weight / (2 * pi * radius_1)

    4) BUT NOW PLEASE NOTICE that there is no radius_2 in both of these equations (torque and speed)! So what’s the reason of this gear (bigger pulley)?... maybe equations are in the fact are not ok?

    5) By the way – if torque and speed are given now, isn’t it natural that there must be a motor power which is combined with this parameters – on the other hand – was it required to determine power at the beginning of this post?
    6) Any other tips for this application?

    Thanks for anyone who will support me a little bit.
    Attached Images Attached Images

  2. #2
    Associate Engineer
    Join Date
    May 2016
    excuse me I´m trying translate your question. I would know the procediment step for step and your objetive. are you designing this machine? so. you are calculating the dimensional and dinamic parameter to motor selection. I belive that can support you but need know the procediment that you is calculate.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts