Velocity of pulley when spooling line?

1. Jul 30, 2010

Wallys

Hi.
I have a scenario where I am spooling line onto a hollow housing of given minor and major diameters. The velocity of the line being fed into the housing is determined by a feed-pulley of known diameter and r.p.m. I need to calculate the r.p.m. of that the housing needs to be turned in order to acommodate even spooling. Can someone help.

2. Jul 31, 2010

sophiecentaur

Do you want the housing (drum?) to have a peripheral speed equal to the line velocity however much line is wound inside the drum? (Is that what you mean by "even spooling"?)
To relate rotation speed to line velocity you can just use
line speed = 2π r f
where f is the rotation rate in turns per second and r is the coil radius.
I guess the best way to ensure this is to calculate the speed needed for the empty drum to fill at the right speed and to operate the drum at this speed. You could use a slipping mechanism to allow the drum to slow down as it fills up. Some sort of fluid drive could achieve this. Otherwise you would need a servo control to match the speeds - using the above formula. Not a trivial problem, though.

3. Aug 2, 2010