Calculate torque/power needed to lift a 4 kg load

[barrygold]

Hi All.
I am looking to determine the torque/power/rpm. needed to lift a 4 kg. load
150 mm vertically in 10 seconds.
I need to use a 6 volt dc. gear motor mounted vertically and connected to a 12 mm
dia. acme lead screw ( steel ) with a 3 mm pitch and 48 % efficiency.
The lead screw nut witch the load is connected to is also steel.
The load guide is a steel tube with a brass bearing.
Please see attached drawing.

Best regards and thanks in advance.

 

[SteamKing]

The following article supplies what you need:

http://en.wikipedia.org/wiki/Leadscrew#Mechanics

 

[russ_watters]

All of the needed information is in that post. Start with the definition of work to find the work required to lift the weight. then divide by time to find the power. Then divide by efficiency to get the input power needed.

The pitch of the screw tells you how far the weight moves every time the shaft rotates once, from which you can find rpm.

With power and rpm, you can find torque.

Just give it a try with what you already know.