Re: [CAD_CAM_EDM_DRO] STEPPER TORQUE THREAD

Use a long string, so that there is time to accelerate up to a fairly
high speed. You know how fast you are turning from the step rate -
and the motor eathier keeps up, or starts missing steps at which point
torque falls off and the drum moves unevenly or starts to turn
backwards. Basically you can load up a weight and see how fast you
can move it before this sytarts to happen, then try a different weight
until you have as much of the curve as you need.

Chris

> << I turned a drum 2" in diameter and mounted it on the shaft, then hung
> a weight on a string. That allowed measurement of both holding torque
> and 'lifting' torque over a reasonable range of movement.
>
> Chris
> >>
> Problem with this is, most of us have good torque at low speed. When and how
> fast the torque drops off in relation to RPM is what most need to know. A
> dyno using water or air or possibly electrical resistance would be the
> easiest to construct and calibrate. Model airplane props and a tach might be
> a low tech but useful method. Various diameter / pitch props would need to be
> tested and performances plotted for interpretation.
>
> Peter
> THRD, Inc.
>
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