Re: Newbie question: Motor sizing

Art,

Keep in mind the things I am out of my depth about. I am a EE and I
have no machining experience except for running a manual Bridgeport
when I was in college a couple of summers 30 years ago.

What I am going on is the manual X/Y axis feed handles were about 5"
in diameter, so the moment arm was 2.5". I kind of remember being
yelled at if I applied more than 5 to 10 lbs of force on the handle.
That took using a fist and I was told not to.

5 lbs is 80 oz, over a 2.5" moment arm it becomes 200 in-oz, on a 5
TPI leascrew it becomes 2pi*200 in-oz*5TPI/16*.75 eff = 294 lbs. 10
lbs of tangential force on the handle would be 589 lbs. I picked a
number in between, 500 lbs.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Art Eckstein <axtein@d...> wrote:
> Mariss,
> Ok, I understand all that you have said EXCEPT one of
the "assumptions"
>
> In the example, you use 500 lbs of "push". Is this a realistic
number or
> how did you arrive at this figure??
>
> I ask, as I am trying to see if some servo motor I have will work
using
> your formulas. Any help will be appreciated.
>
> <snip>
>
>
>
> >(5) Let's go thru an example of the above using what you have (and
> >many guesses on my part).
> >
> >Assume the following:
> >
> >TPI = 5 turns per inch
> >Lbs = 500 lbs of push needed
> >IPM = 60 inches per minute max for your "work" speed
> >eff = 75% (0.75) for your leadscrew.
> ><snip>
>
>
>
> >Hope that helps, hope I did the math right.
>
>
> AND YES, it helps:-})
>
>
> >Mariss
> >
> >
>
> Bubba
>
> OLDER THAN DIRT
> Country Bubba
> (Actually the inventor of Country and Bubba)
>
> axtein@d...
> LaGrange, GA
>
> http://members.dicomm.net/~axtein
>
>
> [Non-text portions of this message have been removed]