Re: Stepper Motor size

Hi,

A handy equation to convert in-oz torque to Lbs of "push" or thrust
on a leadscrew is:

Lbs = (in-oz times 2pi times TPI times %) / 16

Where TPI is leadscrew turns per inch and % is leadscrew efficiency

If you have a 5 TPI leadscrew with 85% efficiency and a 2,000 in-oz
motor, then push is:

(6.28 X 5 X 2,000 X 0.85) / 16 = 3,336 Lbs, or over 1.5 tons. That's
a lot isn't it?

Mariss

--- In CAD_CAM_EDM_DRO@y..., karl@c... wrote:
> I'm looking for stepper motors for my second CNC mill. My
Bridgeport
> Series 1 has LARGE steppers. I don't have the specs. but I guess at
> least 2000 oz/in.
>
> My second mill is a full size bridgeport type knee mill which needs
a
> CNC upgrade. I'm using Ahha Artisan FWIW. The control uses 48 volts
> and needs 8 pole motors.
>
> Anyway, I'm looking for large steppers and can't find any. My first
> question is what size do I really need? I do the conversion from
> oz/in to foot pounds and steppers seem really puny. For example,
540
> Oz/in. = 2.8 foot pounds. A typical power feed is 35 to 70 foot
> pounds.
>
> Anyone have a source for large steppers? Preferrably used, or at
> least inexpensive.
>
> Karl