Re: Calculating stepper power

Hi All:
I have an application for a stepper that needs to be able to lift and
lower a load repeatedly at frequent intervals for long durations using a
ballscrew.
Here's the stats:
Weight to lift...100 lb max
Pitch of screw...0.200"
Speed of lift or lower... 20" per min max
Belt reduction...1:2.
Typical motion stroke... 0.020"
Typical duration of action ...8 hours

My question is: how do I set up the calculation to determine the size of
stepper I need assuming negligible friction in the guide rails (linear ways)
and screw (ballscrew) and allowing a decent margin of safety.
The application demands good response time and I don't want to let the
system get hot, so I'm thinking to overbuild rather than go too skimpy.
Thanks in advance
Cheers

Marcus