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

In summary, the conversation discusses the need to find the horsepower (HP) of a motor and appropriate gear box for a rubber on steel calendar machine. The load applied to press the paper is 200 kg/m2 and the required rotating speed is 100 rpm. However, the calculation of HP requires knowledge of the rolling resistance, which can only be determined through experimentation or by scaling from existing machines. The use of formulas is not reliable in this case due to the nonlinear nature of rubber.
  • #1
rishitmevada
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TL;DR Summary
uired
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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  • #2
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.
 
  • #3
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.
 
  • #4
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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Likes Asymptotic and phinds

1. How do I determine the required power (HP) for electrical motors?

The required power (HP) for electrical motors can be determined by using the following formula:
HP = (Volts x Amps x Efficiency) / 746
where Volts is the voltage of the motor, Amps is the current drawn by the motor, and Efficiency is the efficiency of the motor.

2. What is the efficiency of an electrical motor?

The efficiency of an electrical motor is the ratio of output power to input power. In other words, it is the percentage of energy that is converted into mechanical power by the motor. Typically, the efficiency of a motor ranges from 70-95%.

3. How do I determine the voltage and current of an electrical motor?

The voltage and current of an electrical motor can be found on its nameplate, which is usually located on the side of the motor. It will list the motor's rated voltage and current in amps. If the nameplate is not available, you can use a multimeter to measure the voltage and current while the motor is running.

4. Can I use the same motor for different power requirements?

It is not recommended to use the same motor for different power requirements as it can lead to overheating and damage to the motor. It is important to choose a motor with the correct power rating for the specific application to ensure optimal performance and longevity.

5. How do I convert power (HP) to other units of measurement?

To convert horsepower (HP) to other units of measurement, you can use the following conversion factors:
1 HP = 745.7 watts
1 HP = 0.7457 kilowatts
1 HP = 33,000 foot-pounds per minute
1 HP = 550 foot-pounds per second

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