Re: Motor calculations? Help!

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

> cnc_4_me wrote:
>
> >Jon, I do not see this the same way you do. Don't you think the
> >continuous current rating is more important than the peak current
> >rating? 28 Kg-Cm / 2.44 Kg-Cm/Amp = 11.5 amps, a gecko would

still

> >have plenty of reserve. 20 amp limit would still give 49 Kg-Cm. I
> >wish i had one of these motors for my Z axis.
> >
> >
> What's the peak rating for, if you never can get closer than 20% of

it?

> I might be worried that you might not be able to break static

friction on

> the table with 20 A. What is the leadscrew pitch, and is the screw

directly

> driven by the motor, or is there a belt reduction?
>
> What horsepower and spindle taper does the machine have?
>
> Jon

From what I understand from reading these forums is that any force
much greater than continuous rating isn't to usable, maybe for a
fraction of a second for fast acceleration. Maybe if he adjusts
acceleration so it does not snap your eyeballs it would be ok.

49 Kg-Cm is about 47 lb-in. Nothing to sneeze at.


I guess what I am getting at is I would not try to discourage this
guy and say it will not work. I think it is very likely it will
work with slower acceleration and with 30% less speed on X and Y
because of voltage restrictions with Gecko drives. Rutex would give
him full speed and slightly higher acceleration.


Wally