Re: wrong guy, but have servo question.

> Hi,
>
> The peak power a servomotor can generate is:
>
> 1) P = V squared / 4R
>
> Where P is mechanical power in Watts
> Where V is your power supply voltage
> Where R is your motor's armature resistance in Ohms
>
> 2) Torque at peak power is:
>
> T = (2 times W times RPM) / 1351
>
> Where T is torque in in-oz
> Where W is power in Watts
> Where RPM is, uh no-load RPM?
>
> Also know:
>
> 3) 1HP is 746 Watts
> 4) 1 HP is 550 ft-lbs/sec.
>
> Example:
>
> You have a 24VDC rated 3000 RPM (no load) motor that has a 1 Ohm
> armature resistance. You have a 5 pitch leadscrew. At peak power,

> much thrust will it have (in lbs) and what will be the speed?
>
> Let's take care of speed first. Peak power occurs at 1/2 no-load
> speed, so speed is (RPM/leadscrew pitch)=(1500/5)=300 IPM
>
> Use (1) to calculate power: (24 squared)/(4 times 1)= 144 Watts.
>
> Use (2) to calculate torque: (144 times 1351)/1500 = 129.7 in-oz
>
> Use (3) to calculate HP: (144/746)= .193 HP
>
> To calculate thrust: 130 in-oz on a 5 pitch leadscrew is a .03183"
> moment arm, 1/(2 times pi times 5). Thrust will be 130/.03183 or

> oz, or 255 lbs.
>
> Hope this helps. The above does not take into account leadscrew
> efficiency.
>
> Mariss
> Geckodrive Inc.
>
>
> --- In CAD_CAM_EDM_DRO@egroups.com, "Wally K" <cnc4me@u...> wrote:
> > Jon, in you last post you said "Wally K wrote:" the following,

> it
> > was Ron that wrote it. I am using steppers on my system.
> >
> > Ron is doing a bridgeport type retrofit and has been trying to
> > determine how much HP he will need to move his table and if his
> > servos are big enough. And i have been trying to gather
> information
> > about his system so we could help.
> >
> > Personaly i think his servos are to small for this type of a mill
> but
> > i do not have any servo experance so i hesitate to just say it as
> > fact.
> >
> > I have a few questions on servos that you could clear up for me.
> > First i thought servos were chopped drives. But it seems that

> > people here talk about a servo rated at a certain voltage, that

> > the voltage they run it at. Example, the servo is rated at

> > So they run it at 24vdc.
> >
> > Second what do the torque curves of a servo look like.
> >
> >
> > Wally K.