Re: oz*in NOT oz/in

Dave,

A step motor's torque is the inverse of its speed. Here's why:

The motor winding has inductance (L). Inductance has a property
called inductive reactance. It is measured in Ohms and is
proportional to frequency (step rate).

This means if the step rate doubles, inductive reactance also
doubles. According to OHm's Law (I=V/R), current thru the winding
will be halved. Torque is directly proportional to current, so it
will be halved as well.

Power is speed times torque. If speed is doubled and torque is
halved, the product of the two (RPM * oz-in) remains the same. This
means a step motor's output power is independent of speed. It has
constant output power.

Mariss

--- In CAD_CAM_EDM_DRO@y..., "dave_ace_me" <davemucha@j...> wrote:
> Hi Doug,
>
> I'm on real shakey ground here so I am only going by what seems to
> make sense to me.
>
> If one has a block of some weight with a thread in it and a
threaded
> rod is in that hole. a certain amount of rotational force (foot
> pounds) will be needed to lift that weight with that TPI thread.
>
> a finer thread would need less torque.
>
> at least that is how it appears to me.
>
> now, the fact that stepper output force is not linear over the
speed
> range, now that is something else.
>
> Dave
>
>
> --- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@c...> wrote:
> >
> > Those of you who are trying to work out
> > torque vs table push (using units analysis)
> > will never get it to work out because:
> >
> > torque is measured in 'force*lever arm'
> > in other words, oz*in lb*feet N*m
> >
> > etc, NOT oz/in , lb/ft etc.
> >
> > (Yes I know oz & lb are not exactly units
> > of force, we should be using Slugs but I'm
> > afraid that will lead to even More Confusion!).
> >
> > Doug Fortune
> > http://www.cncKITS.com NEW -> 1 KW power supply kits
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > .