I have a client that needed to test torque.  The first idea they had was
to use a clutch to add load to the shaft, and attach a load cell (S
type) at a tangent to the clutch plate.  As predicted, the clutch got
too hot for reasonable use.  So they got a 'magnetic brake' unit, that
comes with an electronic unit that varies the intensity of reistance.
They still use the load cell at a tangent to the new mag brake.  It
works like a charm.  They read volts, current, and torque into their PC
and plot it under production test.

Chris Eddy
Pioneer Microsystems, Inc.

Anne Ogborn wrote:

> Use a strain gauge. Easiest is to clamp a beam to
> your shaft, and restrain the end of the beam with a
> rod in tension.
>
> Epoxy a strain gauge to the rod, and away you go.
>
> Annie
>
> or, if you want something easier to deal with electronicly
> but a bit messier mechanically (and if you can cope with
> the rotation)-
> attach a rotary pot to the shaft and restrain the shaft with a
> torsion spring.
>
> guys, when you're looking for sensors, ya gotta have some
> idea
>
> a) how much input to expect (the scale)
>
> and
>
> b) how much the sensor can affect the object (as here - how rigid
> do I need my torque sensor to be?)