Calculating Power Transmission with Belt and Rope Drives: A Comprehensive Guide

In summary, the first question involves determining the power that can be transmitted in a belt drive with a 150° angle of lap, 20m/s belt speed, and 1400N max tension. The answer is 10kW. However, if an idler pulley is used to increase the angle of lap to 210°, the power that can be transmitted increases to 12.56kW. The second question involves determining the maximum power and corresponding speed of the smaller pulley in a rope drive with a 40° groove angle, 4.5m distance between shafts, and a rope with a mass of 4kg/m and a maximum tension of 20kN. The answers are
  • #1
Brabs23
8
0
Two questions I am a bit stuck on, any kind of help would be appreciated :)

1 - In a belt drive the angle of lap on the small pulley is 150°. With a belt speed of 20m/s and a max tension of 1400N, the greatest power that can be transmitted is 10kW. What power could be transmitted for the same belt speed and max tension if an idler pully is used to increase the angle of lap to 210°. (It may be assumed that centrifugal effects are significant and the mass of the belt is 0.75kg/m)

I know the answer is 12.56kW, but even working backwards is confusing me!


2 - Power is transmitted by a rope drive between two shafts 4.5m apart. The pulleys are 3m and 2m diameter snd the total groove angle is 40°. If the rope has a mass of 4 kg/m, and the max tension is 20kN, determine the max power which the rope can transmit, and the corresponding speed of the smaller pulley. Coefficient of friction is 0.2.

Again .. the answers are 446kW and 390 rev/min
 
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  • #2
What relevant equations do you think you need?
 

FAQ: Calculating Power Transmission with Belt and Rope Drives: A Comprehensive Guide

How is power transmitted through belt and rope drives?

Power is transmitted through belt and rope drives by the frictional force between the belt/rope and the pulley or sheave. When the belt or rope is wrapped around the pulley/sheave, the force applied to one end of the belt/rope is transferred to the other end, causing the pulley/sheave to rotate and transmit power.

What factors affect power transmission in belt and rope drives?

The factors that affect power transmission in belt and rope drives include the coefficient of friction between the belt/rope and the pulley/sheave, the tension in the belt/rope, the angle of wrap around the pulley/sheave, and the speed of the pulley/sheave.

How do you calculate the power transmitted through a belt or rope drive?

The power transmitted through a belt or rope drive can be calculated using the formula P = (T1-T2)*V, where P is power in watts, T1 and T2 are the tensions at the tight and slack sides of the belt/rope respectively, and V is the velocity of the belt/rope in meters per second.

How do you determine the size of the belt or rope for a specific power transmission application?

The size of the belt or rope for a specific power transmission application can be determined by considering the power to be transmitted, the speed of the pulley/sheave, the center distance between the pulleys/sheaves, and the type of material used for the belt/rope. These factors can be used to calculate the required belt/rope width, thickness, and length.

Are there any safety precautions to keep in mind when working with belt and rope drives?

Yes, there are several safety precautions to keep in mind when working with belt and rope drives. These include wearing appropriate personal protective equipment, ensuring proper tension and alignment of the belt/rope, and avoiding contact with moving parts. It is also important to regularly inspect and maintain the belt/rope and pulley/sheave to prevent accidents and ensure efficient power transmission.

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