Torque Trax Torque Measurement

There is a "Tork-Trak" system by Automated Controls/Cooper Power Tools that uses transducers interfaced with a computer. It seems to be used for fastening applications (e.g., torquing bolts). I don't know if it would be adaptable to your larger-scale use, but you could try contacting the manufacturer.

The only possibility is to bond strain gages and use a conditioner (with on board batteries) on the shaft, and sending by radio waves the strains measured. Knowing the strains and the shaft diameter you can compute the torque. Such telemetry systems are available either as parts to buy or as services. The term is "telemetry on rotating shafts".

In general precision is high enough. The system allows also a dynamic analysis since the acquisition ratios are high.

I found it. It's Torquetrax by binsfeld at binsfeld.com. And Nick had it exactly right.

Thanks everybody.

Thank you for the comment. In fact I do participate less and less since I consider that an answer has to be given ONLY if the commentator has a knowledge about the subject. I do not like to only give a comment from the air, unfortunately in comparison with the past the more and more participants give answer without any ground or relation to the question.

Be careful about the source NOT all telemetry systems are worth the price which is asked for.