Re: [CAD_CAM_EDM_DRO] measuring motor torque

Vlad Krupin wrote:

>That really depends on your target RPM at which you want to measure the
>torque. If you want to know the highest torque achievable (when stalled)
>then you can rig up a pulley and a spring, see how far the spring extends
>when current is applied, and then see how much weight it takes to extend the
>spring by the same amount by just hanging weights off of it. I remember
>doing that during one of my physics labs back in middle school. You can get
>a remerkably accurate measurement.
>
>I do not know of any simple way to figure out the torque curve for a given
>motor. However, most of those curves seem to be quite similar for motors
>that are at least somewhat similar in construction and operation. So if you
>know the torque at zero speed (easy to measure) and the maximum no-load
>speed (you probably already know that one), you can get a pretty good idea
>of what torque to expect at a given RPM.
>
>
>

The torque curve of a DC brush motor is almost perfectly flat in the
area where
it is safe to run the motor. At the upper end of the peak torque/peak
current
range, the curve may flatten just the slightest bit before you get into the
area where the magnets are permanently damaged. Speed has almost no
effect on the torque/current ratio (Kt).

Jon