The velocity ratio of weston differential pulley is
Answers
Answer:
This means that the velocity ratio of our pulley system is 2. However if the pulley is 100 % efficient and the velocity ratio is 2 then the mechanical advantage is also 2 and that means that the load is double the effort. This means, for example, that you can lift a load of 100 N using an effort of only 50 N.
Answer:
The Weston Differential Pulleys
Thomas is best known for creating ‘The Weston Differential Pulley’ which states when moving large loads with minimal effort a mechanical advantage (MA) is given.
Thomas is renowned for his creation of The Weston Differential Pulley where two pulley wheels of differential diameter are mounted on the same axel. What this is referring to is the speed of the cable rolling onto a larger pulley in comparison to rolling onto the smaller pulley allowing you to lift large loads with minimal Force effort. The ratio of the two diameters provides you with a Velocity ratio. From this, provided you have the weight of the object required to be lifted you can calculate the Force Effort and the Mechanical Advantage.
The formula for Mechanical Advantage is:
Where:
W= the load of the body
F= the force on the body
If the MA is greater than 1, this suggests that the load is greater than the force you apply for it to be moved. If the MA is less than 1, the load needs more of a force to be applied for it to be moved.
In relation to the ‘principle of conservation of energy’ you do not put all your energy into something and receive nothing, therefore the Mechanical Advantage you get from a pulley is usually at the expense of needing to move something further or faster than you would otherwise. If we apply a smaller force we need to move it through a larger distance and if we apply a smaller force we need to move it through a larger distance.
Similarly to the mechanical advantage formula, the velocity ratio is the difference between how much the input force moves than the output force. The formula for velocity ratio is shown below:
Where:
hf = Differential height of load W
hw = Differential height of load F
If the velocity ratio is greater than 1, it means the force used over a longer distance or at a faster speed has moved the load.
To calculate the efficiency of the pulley, a Mechanical Advantage ratio and Velocity Ratio would be used to work out an Efficiency Ratio as they should have similar values. The ratio used is:
Practical Applications Using Differential Pulley
Understand Differential Pulley by demonstrating the mechanical advantage of different combinations of pulleys and a simple wheel and axle using TecQuipment’s Pulley Kit (ES10).
To use the TecQuipment’s Pulley Kit, an essential base unit known as the TecQuipment Work Panel (ES1) is needed.
