It might work if you applied a small voltage (value experimentally determined) to the motor to maintain tension while it is back-driven and then full voltage to retrieve the line.

 

It might work if you applied a small voltage (value experimentally determined) to the motor to maintain tension while it is back-driven and then full voltage to retrieve the line.

I think this is where I will start. I will then add complexity as needed. I like starting designs with the simplest possible solution first.

Thanks All!

 

chuck:

I tend to put on the table everything from the complex to the absurd. Then start whittling it down a bit. Like what must I absolutely need, what would I like to have etc. and go from there. Te brainstorming session seems to be the most fun. Nothing is off the table.

 

How much tension ? Short experiment , 100 ft. of 3/32 nylon line, fixed end 32 in. high, other end over a pulley
, 32 in. high tied to a cup. It took 5.5 oz. of nuts & bolts to make line just clear the ground. If line is allowed to drag on ground, 2 oz. would do. I like MrAl's approach, post # 15.

 

To compute torque, you just need the moment. The radius of the pulley and the force in oz( F*(moment) and you get units of oz-in.

 

For simple ( multiple meanings ) , found a 3 lb. tensioner with 44 in. cable. Attach a 48 in. drum to small drum
& have 2 oz. with 100 ft. line ? Or gear up a smaller drum ?