# Thread: fundamental calculations - explanation

1. ## fundamental calculations - explanation

Hi,
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.
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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?
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Now let’s calculate a torque_motor and speed – it seems that tutorial example is the same:
so:
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.?
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speed (0,2m/sec)
rps_gear2 * 2 * pi * radius_2 = velocity_weight -> rps_gear2 = velocity_weight / (2 * pi * radius_2)
so
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.

2. 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.