Contactless Torque Meter

Hello,

Can you be a little more specific about your application? I may be able to help. I have quite a bit of experience with torque measurement, specifically with in-line rotating torque transducers. Rotating torque sensors are nice because many of them also have an encoder that can relate the measured torque to angle of rotation.

A great place to start your search would be at GLOBALSPEC!

How can you have a contactless torque device? Torque is all about measuring a force that generated by a moving object (shaft) rotor, motor. You can measure the speed of rotation using light but not torque. You have an oximoron there.

There are people selling devices for AC electric motors that make this claim, but it is a false claim; from an engineering standpoint anyway. What they do actually is measure the power factor of the motor because they kow that power factor varies by motor loading. then they use that to determine a percentage of Full Load Torque based on assumptions about the motor from typical empirical data they store in memory and use to create a motor model to compare to. Some of the more sophisticated versions allow you to "tweak" that motor model, but no matter what it is not a true measurement of shaft torque, it's a "guesstimate" with some limited feedback.

The real way to measure torque is to use any sort of position indicator on both the

drive end and the load end of a rod that you know the properties of. Then, just compare the phase difference between the two.