me to find the required power (HP) of these electrical Motors

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Discussion Overview

The discussion revolves around calculating the horsepower (HP) required for electrical motors to rotate rolls in a paper processing setup. The context includes considerations of material properties, load conditions, and operational parameters, focusing on the theoretical and experimental aspects of the problem.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant requests assistance in calculating the required HP for motors based on specific dimensions and load conditions of the rolls involved.
  • Another participant notes that the power needed is influenced by rolling resistance and friction, which are typically determined experimentally rather than through calculations.
  • A different participant suggests that understanding the deformation mechanics of the rubber roll face is essential for accurate calculations, highlighting the nonlinear nature of rubber as a material.
  • Further contributions emphasize the need for empirical testing or scaling from existing machines, pointing out that rolling resistance is affected by factors such as rubber formulation, nip pressure, and running speed.

Areas of Agreement / Disagreement

Participants generally agree that empirical testing is crucial for determining the required HP, and there is no consensus on a definitive calculation method due to the complexities involved.

Contextual Notes

Limitations include the dependence on specific material properties and the need for experimental data to accurately assess rolling resistance and other factors influencing power requirements.

Who May Find This Useful

This discussion may be useful for engineers and technicians involved in mechanical design, particularly in applications related to rolling mills and material processing.

rishitmevada
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find HP of electrical Motors Required

Dear guys,
As you see in picture, there is a two rolls.

Top roll have a Rubber Surface Coating (Weight : 1000kg, OD:550mm, ID: 448mm, Face Length : 1950mm),
Bottom roll (Weight : 1500 kg, OD:605mm, ID: 535mm , Face Length : 1950mm ) is a steel surface.

Now the paper pass between them, and load applied to press the paper, (Nip Pressure) is 200 kg/m2.

And my question is, How can I calculate HP required to rotate the roll at 100 rpm.

NOTE: i even make the formula table (Attached Herewith) from the another post given in the https://www.physicsforums.com/showthread.php?t=201254, But the load consideration is not there..

Please Help Me to find HP of motor and Appropriate gear box...

Regards, Rigarbage Mevada
 

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The power needed depends on the rolling resistance, or friction. That is normally something that we measure by experiment, not calculate. Formulas are not helpful if we do not know the values of the coefficients.

If you don't have access to a test machine, or to a laboratory, I suggest looking at similar rolling mills and find out what size motors they user.
 
If you really want a calculation (and I cannot tell you how to do such), you will have to get into the deformation mechanics of the rubber roll face. Rubber is a somewhat strange material, rather nonlinear. As Anorlunda has said, an experiment is probably your best option.
 
Ah yes, a rubber on steel calendar. I've seen many of them. As @anorlunda and @Dr.D posted above, there are no equations. You need to run some tests, or scale from existing machines. Keep in mind that the rolling resistance is due to hysteresis in the rubber, so is dependent on the exact rubber formulation, nip pressure, and running speed.
 
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