Motor load weight limit?

[jeleser]

CD,

I've searched all over (both here and other websites) on how to calculate how much weight a motor running through a gearbox can lift. I'm not sure exactly how to word the searches, but I believe I have most of the info I need on the product pages on Andymark. Here's the setup:

If a CIM (http://www.andymark.com/CIM-motor-FIRST-p/am-0255.htm) is inserted into a WormBox (http://www.andymark.com/product-p/am-0917.htm), which then has a 2.5 in shaft going into another WormBox, am I correct in saying the gear reduction is 256:1, since each gearbox has a 16:1 reduction? How much weight could this lift?

Another setup:

3 CIMs are inserted into a 3 Motor Toughbox (http://www.andymark.com/ToughBox-p/am-2388.htm) (12.75:1), 2.5 inch output shaft into a Wormbox (16:1). Would the total gear reduction be 204:1? And how do I calculate how much weight this could lift?


Not really looking for answers on how much can be lifted, just formulas. What information do I need to pull from product pages to calculate this?

[nathan_hui]

You need max torque (at stall current, unfortunately). Gear reduction (make sure it's reduction) multiplies torque (increases, just to check your answers).

for your first example, that is correct. I'll let you do the math (CIM max torque is 343 in-oz)

For the second setup, this is a little harder to do. Someone correct me if I'm wrong, but the torques for the motors in that particular toughbox should be additive (I think the issue was with the current...). I'm not going to check your math, you should know enough by now to check the total gear reduction. For calculating weight, you actually need to know the size of your spool, and that (combined with info you already know) would give you your max weight. But bewarned - this is the max weight your setup can sustain. Actually lifting is another set of equations, but this gives you an excellent upper limit (W_DNE (Weight - Do Not Exceed))

Other formulae you may find useful:

Torque = Force * Distance
This means the torque (you could call it rotational force) is given by the amount of force a lever of length Distance will exert at the end of said lever.

[Ether]

Not really looking for answers on how much can be lifted, just formulas.


http://stanford.edu/~sebell/firstphysics/first_encounter_with_physics.pdf

[Domtech]

I had actually considered such a setup, but after taking a closer look at the WormBox I noticed 2 things:
1. It uses plastic gears.
2.It lists a max output torque of 70 ft-lbs

These must be considered when deciding how to use it.