Re: [CAD_CAM_EDM_DRO] Digest Number 4614

It's called a Prony Brake. It can be used to measure torque at any speed
from full to stall. Do a google search or try:
http://www.tpub.com/content/engine/14037/css/14037_53.htm

If I can stretch my memory back that far, I believe you can do a series of
measurements at different rpms and develop a torque speed curve.


At 12:31 PM 2/17/2006, you 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.

Regards,
Bradford J. Chaucer
bjchaucer@...