Why are winches able to pull more as less is wrapped around the spool?

[sixstringsteve]

As the title states, why are winches able to pull more load when there are fewer wraps on the drum?

 

[frieed]

The motor develops a fixed amount of torque. That torque = the force x distance from the center of rotation. Also written as force (pull) = torque/distance. Since torque is constant, as more wraps go on the drum, the pulling point gets farther away from the center of the drum, so distance increases and force decreases.

 

[sixstringsteve]

Ah, that makes sense. Kind of like the cranks on a bike.

 

[frieed]

Just like..

 

[Kevin B.]

Ah, that makes sense. Kind of like the cranks on a bike.

Yup. It's leverage.

 

[rholbrook]

Thats exactly why I am an accountant and not an engineer. That makes no sense to me.

 

[bobn]

As the title states, why are winches able to pull more load when there are fewer wraps on the drum?

For the same reason that when you can't make your climb in high range, you shift into low range. Even though the drum does not have gears, every wrap of cable produces a different "gear" ratio.

 

[SpeedyVic]

Thats exactly why I am an accountant and not an engineer. That makes no sense to me.

Think of it in these terms. Your Jeep produces a fixed amount of power. Lets say you have 31" tires on and you drive it til the tires wear out. On your next set of tires, you decide to go up to 33" tires. Same Jeep, same power, but now you notice that the Jeep must work harder to get you up to the top of the hill on your way home.

Look at the winch from the side. The first layer of rope is closest to the spool. It is the smallest diameter (31" tire) and the last layer of rope is the largest diameter (33" tire). Though the difference isn't all that huge, the force required to pull the object (your Jeep) is significantly different.

 

[sixstringsteve]

good explanation veyecteaoare

 

[ricsrx]

How exactly does a posi-trac rear-end on a Plymouth work? It just does.

Sorry Steve thats my best answer...


name that movie..

 

[TRD270]

How exactly does a posi-trac rear-end on a Plymouth work? It just does.

Sorry Steve thats my best answer...


name that movie..

My cousin Vinny

So hot...

 

[SLC97SR5]

How exactly does a posi-trac rear-end on a Plymouth work? It just does.

Sorry Steve thats my best answer...


name that movie..

Joe Dirt

 

[rholbrook]

What bobn said now makes sense and then veyecteaoare really finished it up.

 

[STAG]

Joe Dirt

For the win.

 

[mesha]

levers are cool, rotating levers are even cooler.

 

[MikeGyver]

A good benefit of synthetic ropes is that they will dig down into the drum because the rope that isn't under tension is soft, so you can get first or second layer pull power even on a fully loaded drum.