RE: [CAD_CAM_EDM_DRO] Re: What makes a motor a servo? calculating power

Thanks Mariss,

I didn't find it, but the stepper is probably 550 oz/in?

Interesting, but not surprising that a servo is about 2X more powerful for
its size/weight. I'd noticed that steppers seem to be bigger for the same
power (building robots). More wattage in a smaller/lighter package
because...?

If I take half of 170 oz/in for the servo, then about 85 oz/in servo
(possibly less) would be similar to a 550 oz/in stepper in machines they
could drive (gearing needed for servo).

Can I assume that the "300 Watts" printed on my servos is continuous? I
don't have them in front of me, and I didn't find them on a Google search.
Target machine is an RF-31 mill. The 1000 (or was it 2000) line encoders on
them are over kill, I'll have to reduce that. Or does one of your new servo
drivers do that for me?

Thanks for the comparison.

Alan KM6VV

> Subject: [CAD_CAM_EDM_DRO] Re: What makes a motor a servo? calculating
> power
>
> I'll give it a shot.
>
> NEMA-34 triple-stack step motor 7A/phase, 48VDC supply gets 220 Watts.
> NEMA-34 DC servo motor at 80VDC gets 500 Watts continuous, 950 Watts
> peak at 20A.
>
> Stepper is a Superior Electric MO93-FD14
> Servo is from Machine Tool Camp (very nice motor/encoder!)
>
> Both motors are about the same size, 3.375" dia, 5" long for the
> stepper, 6.75" long for the servo.
>
> For you torque afficionados that is 170 in-oz continuous, 500 in-oz
> peak at 20A.
>
> Pound for pound, generally figure on twice the continuous power over
> a step motor.
>
> Mariss
>
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Alan Marconett"
> > <KM6VV@a...> wrote:
> > > Hi list,
> > >
> > > I wonder if similarly constructed servos and steppers (same technology
> > > magnets and laminations?) with similar WEIGHTS (don't laugh just yet)
> > > could be compared? If these things were equal, what would their
> > > ratings be?
> > >
> > > Perhaps someone with a LOT of familiarity with steppers and servos
> > > could pick a pair?
> > >
> > > Just an idea. OK, you can laugh now.
> > >
> > > Alan KM6VV