Hoist info. ?

Math for Hoist
Question 1 : Determine horsepower (electric motor) required to raise appoximately 1000 lbs up 9.5 ft in one minuite.?
Ans.: 1/3 hp eletic motor.

Horsepower Formula is 330000 ft.lb/min = 1 hp

Question 2 : Determine gear ratio to accommodate 1/3 hp electic motor @ 1725 rpm
Ans : 106 : 1

load moves 7" per rotation of hoist drum with a cable. 9'6" requires 16.8 rotations.

Question 3 :Determine gear ratio to accomadate 1/3hp electric motor @ 3450 rpm

Ans :212 : 1

load moves 7" per rotation of hoist drum with a cable 9.5 ft = 114 inches
114 " requires 16.28 rotations of 7drum ( 114" / 7" = 16.28 )
212 : 1 ( 3450 rpm/1628 rotations = 211.9 )

Yes, I believe your arithmetic is correct, BUT I am going to give you some more food for thought!

First, I don't want to know what you are going to lift or move with whatever contraption you are building. I would, however like to know how you plan to drive it? Belt, or chain, or gearbox?

Is the 1000 lb load going to be constant from startup?

To get a 106:1 ratio using chain or belt is going to require some parts that are custom made and very pricey, same with a gearbox.

By using some jackshafts driving other jackshafts you can accomplish your drive ratio,using off the shelf parts, but it begins to get bulky.

I also don't believe a 1/3 horse motor will have any where enough starting torque to move 1000 lbs from a dead lift.

Just my 25 cents.

I have a small collection of parts on hand; so far I thought of going with a chain drive but haven�t excluded using belt or gearbox.

The load would be constant.

That point about starting torque? I am thinking that the motor would need a chance to get up to 1750 rpm to develop full torque and would need to develop quite a lot of rpm to start the load. Also, if the load stopped I wouldn�t be able start it again.

Your 25 cents is worth a million! Thanks

Charles

I'm almost smart enough to know how stupid I am !
Thanks again for your input. Al