Finding Torque on a Roll

[acurry]

I have a roll that is currently free wheeling to a stop. We are in process of sizing a belt to have this stop a bit quicker. The belt manufacturer wants to know max/min torque on the roll.

How should I go about getting this?

 

[CoryPad]

What is used to impart motion to the roll after it has free-wheeled to a stop? That item will be applying some type of force/torque to the roll. You will need to estimate/measure this force/torque.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[acurry]

I have paper on a 1/4 wrap on my roll, with is 2000 lbs and 13 7/8" diameter. My paper moves at 3500 ft/min.

 

[Gearen]

As I understand the question you have a cylinder which is rotating around its axis and you want to stop it.

The cylinder will have a kinetic energy when its rotating. To stop it it will take an equal amount of energy. The size of the torque to apply to stop it will depend on how fast you want it to stop. Unfortunately I dont have my Physics handbook here and I dont remember the equations in my head. If you want I can write it out later.

 

[desertfox]

Hi acurry

You could estimate the torque required to slow the roll down
by angular momentum and impulse theory although this will only give you the average torque required and not the the max or min you requested.

the formula:-

T=I[α]

where

[α]= average angular acceleration = Wi-Wf/t
I= moment of inertia of roll
T= Torque
Wi= initial angular velocity
Wo= final angular velocity
t= time required to stop roll rotating

So in your case Wi would be the initial speed the roll free
wheels and Wo would be zero, t would be the time required or
desired to stop the roll.

regards

desertfox

 

[acurry]

Thanks for the help, much appreciated!