Multiple Pulley Power Transfer

In summary, the conversation discusses using two identical devices driven by one power source using two independent but equal sized V-belts, a double stacked pulley on the drive shaft, and a single pulley on each of the device shafts. The maximum HP rating of the identical devices at 1200 RPM is discussed, with the conclusion that the power stays constant, torque increases, and speed decreases. The efficiency of the belt drive system is also mentioned, and the application for driving two backward curved centrifugal fans is suggested. It is noted that the effectiveness of using these fans depends on the specific application.
  • #1
ggcarmichael
7
0
I would like to drive two identical devices off of 1 power source. I would like to use two independent but equal sized V-belts, a double stacked pulley on the drive shaft and a single pulley on each of the device shafts. If the power source has a rating of 36HP @ 3600 RPM, what is the maximum HP rating of the identical devices @ 1200 RPM? The drive pulley/device pulley would have a ratio of 1 to 3. I've looked for an equation or explanation of how to solve for this but have not been successful. Any assistance would be appreciated.

Thanks,
Gilbert
 
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  • #2
HP = power X time = work done
so if you slow the speeds 3600/1200 you don't gain more work
as it takes longer

but you do gain power 3 times the power but at a cost of speed
minus the friction losses
 
  • #3
ray b said:
HP = power X time = work done
so if you slow the speeds 3600/1200 you don't gain more work
as it takes longer

but you do gain power 3 times the power but at a cost of speed
minus the friction losses

That's all incorrect, sorry ray.


Power = torque x speed

So (neglecting friction), if your pulley ratio is 1:3, you will increase the torque by 3 times, decrease the speed by 3 times, but power transmitted will remain the same.

With 36hp being developed at your drive shaft, you'll never get more than this at your 'device shafts'.
 
  • #4
Thanks for the responses. So the power stays constant, torque increases and speed decreases. So the two devices would have a max HP of 18 each (not accounting for drive train losses)? Is there a way to take advantage of the increase in torque at the device shafts?
 
  • #5
ggcarmichael said:
Thanks for the responses. So the power stays constant, torque increases and speed decreases. So the two devices would have a max HP of 18 each (not accounting for drive train losses)? Is there a way to take advantage of the increase in torque at the device shafts?

Exactly. Be careful not to underestimate your drivetrain losses with belt/chain type systems.

Taking advantage of the torque increase is exactly what you do when using a lower gear on your bike, or in a car. How this can be applied to give advantage to your 'device' depends entirely on what your application is, and what you're trying to do.
 
  • #6
I had anticipated 80% efficiency in the belt drive system. I plan to drive two backward curved centrifugal fans. Will driving these types of fans be more more advantageous than driving another type of device?
 
  • #7
ggcarmichael said:
I had anticipated 80% efficiency in the belt drive system. I plan to drive two backward curved centrifugal fans. Will driving these types of fans be more more advantageous than driving another type of device?


It depends entirely on what you want to do. Driving centrifugal fans will be a pretty poor solution if what you're trying to do is compress air to inflate car tyres, yet they could work quite well for shifting contaminated air out of a spray paint booth.

What's your application?
 
  • #8
I don't need pressure - I need to continuously move a large volume of air. I'm essentially creating a wind tunnel for experimenting with aerodynamics.
 

What is "Multiple Pulley Power Transfer"?

"Multiple Pulley Power Transfer" is a mechanical system that utilizes multiple pulleys to transfer power or force from one location to another. It can be used to increase or decrease the amount of force applied, change the direction of force, or transfer power over longer distances.

How does the number of pulleys affect the power transfer?

The number of pulleys used in a multiple pulley system can greatly affect the power transfer. Each additional pulley adds friction and decreases the overall efficiency of the system. However, using multiple pulleys can also allow for a greater mechanical advantage and increase the amount of force that can be transferred.

What are the advantages of using multiple pulleys in power transfer?

Using multiple pulleys in power transfer can provide several advantages. It can allow for a greater mechanical advantage, meaning less force is needed to achieve a certain amount of output force. It can also allow for the transfer of power over longer distances with minimal energy loss. Additionally, using multiple pulleys can provide a more stable and balanced transfer of power compared to a single pulley system.

What are the limitations of multiple pulley power transfer?

While using multiple pulleys can provide several advantages, there are also limitations to consider. As mentioned before, each additional pulley adds friction and decreases the overall efficiency of the system. This means that the amount of power that can be transferred may be limited. Additionally, the more complex the system, the more maintenance and potential for failure there may be.

How is multiple pulley power transfer used in real-world applications?

Multiple pulley power transfer is used in a variety of real-world applications, such as cranes, elevators, and weightlifting equipment. It is also commonly used in vehicles, such as cars and bicycles, to transfer power from the engine or pedals to the wheels. In industrial settings, multiple pulley systems are often used in conveyor belts and other machinery to transfer power and move materials.

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