Mechanical advantage from pulleys

[kashyap]

From Where can i get info about the mechanical advantages that we get from different configurations of pulley?

 

[dvd]

The torque at each pulley will vary with the ratio of the pulley pitch diameters.

 

[Curmudgeon]

As a somewhat over-simplified answer:

The mechanical advantage gained from a -set- of pulleys (such as a block and tackle) will most commonly be determined as follows:
'cut through' the center of all the cables - and count how many total cables (N) are being used (including the 'input' cable)
Mechanical advantage will (usually) be (N-1)/1

It is quite possible to create unusual configurations, though, with very different advantages. For any out-of-the-ordinary situations, it is best to carefully examine the specific actions taking place.

Curmudgeon

 

How is the Mechanical advantage of a gear system found?

 

[sbc]

With gears or sprockets, simply count the teeth
of each gear, then devide. A 10 tooth gear driving
a 60 tooth gear wil have a ratio of 6:1. With pullys
the pitch diameter must be found & used. If your
assembly is not accessible, you can rotate the assy.
and count the # of turns of the input shaft needed
to rotate the output shaft 1 turn.

 

[solidfriend]

Is this related to rope hoist and hook mechanism?