roller conveyor calculations?

[bmw318s70]

hi. I am trying to buil a spreadsheet for calculation the required HP of roller conveyors.

The setup of the conveyor is te following:

Motor connected to a gearbox. Output sprocket linked to a roller sprocket. All rollers linked toghether.

This conveyor should move a pallet-load of X lbs, at Y feet/minutes. The various speeds are reached by changing sprockets/gearbox, and the motor size needs to accomodate the speed and weight requirement.

The conveyor will be operated through a VFD , so the accel time will be adjustable to 1 second (this will be a constant)

I can figure out all the HP required to move the rollers, chains, sprockets, etc.. but dont know how to include the pallet-load into acount. There is no "friction" per say as the load is "free-rolling" on the rollers, but I still need to get it moving in 1 second, and then keep it moving.

Let me know!

 

[mcguirepm]

The additional force from the product is a simple equation based on the material in contact with the rollers. The formulae is simply F=uW where u is the rolling friction and W is the weight of the product in pounds.

For u us the following for steel conveyor rollers.
Metal u = 0.01 to 0.02
Plastic u = 0.02 to 0.04
Wood u = 0.02 to 0.05

I always use the higher number in th erange just to be safe.

Once you have the tangential force you can calculate the torque require to turn the rollers.

Respectfully,
Pat

 

[Luza]

Dear bmw318s70
To build a spreadsheet as you require, is not so simple. Of course you may start from a theoretical-basis using the well-known principles of mechanics, but in order to get reliable results, calculations need lots of experience and trial-base modifications and adjustments.
In order to help you, I suggest you take a look into

http://www.hytrol.com.

There are LOTS of conveyors and: Are you going to convey pallets only..? if yes, there is a special Drag Chain Conveyor (model DC-60) specially engineered for this application. HYTROL issues useful standard specifications and a Load / HP capacity chart. Compare them with your calculations.

Good Luck !!