Calculating Weight Pull for a Pulley System

In summary, the individual is trying to lift a 230lb weight by using a 2 1/8 inch dia. pulley, followed by a 17 feet horizontal distance to a 3 inch dia. sheave block, and then dropping straight down 25 feet to another 3 inch dia. sheave block with a 30 degree angle. The cable then goes down at a 110 degree angle for 8 inches to a 3 inch sheave block on a swivel hook, and finally to another 2 1/8 inch dia. pulley and a winch. To lift this weight, the winch must be able to pull at least 230 lbs, and the individual is using a 1
  • #1
warrior chief
1
0
i have a 230lb weight i need to lift 12feet in the air. i have a 2 1/8 inch dia. pulley directly above it, and then 17 feet horizonally i have a 3 inch dia. sheave block. Than i drop straight down 25 feet to another 3 inch dia. sheave block which is turned at a 30 degree angle to the sheave block above, but is still in line with the sheave block above. i then go down at a 110 degree angle for 8 inches to a 3 inch sheave block on a swivel hook, so i can line up with another 2 1/8 inch dia. pulley and onto a winch. what must my winch be able to pull to lift this 230 lbs. i am using a 1/8 inch steel cable rated at 1800 lbs break. Thanks ; Warrior Chief
 
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  • #2
There is a fundamental principle that all a theoretical rope/wire/string can do is pull in a direction colinear with the rope/string/wire.

So draw a diagram. Start at the weight and label the force the cable must supply. Then follow the cable, being careful what happens to the cable at each sheave. Come back and show your work.
 
  • #3
Post a diagram of your setup...it sounds a bit confusing.
 

What is a pulley system?

A pulley system is a simple machine that uses a grooved wheel and a rope or cable to lift or move heavy objects. It works by changing the direction of the force needed to lift an object, making it easier to lift.

What is the formula for calculating weight pull in a pulley system?

The formula for calculating weight pull in a pulley system is: weight pull = (weight of object / number of supporting ropes) + (frictional force x number of supporting ropes).

What is the purpose of calculating weight pull in a pulley system?

The purpose of calculating weight pull in a pulley system is to determine the amount of force needed to lift an object. By knowing the weight pull, you can choose the right pulley system and rope/cable to safely and efficiently lift the object.

What factors influence the weight pull in a pulley system?

The weight of the object and the number of supporting ropes are the main factors that influence the weight pull in a pulley system. Frictional force between the ropes and the pulleys can also affect the weight pull.

How do I choose the right pulley system for a specific weight pull?

To choose the right pulley system for a specific weight pull, you need to consider the weight of the object and the number of supporting ropes. The more supporting ropes you have, the less weight each rope has to lift, making it easier to lift the object. You also need to take into account the frictional force, as it can add to the weight pull and make it more difficult to lift the object.

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