Torque transducers have come a long way over the years. Previously, you had to choose between accuracy and cost effectiveness. Strain gauge torque transducers provide the highest possible accuracy in measurements, but they’ve traditionally been bulky and costly. That made them prohibitively expensive for most manufacturing settings, and their size made them difficult if not outright impossible to implement effectively in a factory setting. That left strain gauge torque transducers best suited to research and development, where they’re not required to be integrated into a production environment, and their impressive accuracy is essential to doing the necessary work.

Low-cost methods have also been attempted, but they’re generally insufficient. Non-direct methods of measurement can detect something such as a change in electrical power consumption, but this is typically too inaccurate to be reliable. Luckily, modern sensors can be both accurate and easily implemented in the manufacturing setting, giving manufacturers toque sensors that are within 0.05% of full scale strain gauge units. Additionally, these torque transducers can be designed directly into production equipment, making them ideal for factories. They also cost about 60% of what a full-sized system would cost, making them far more affordable.

How They Work

But how do torque measurement transducers work? When a conductor is compressed, it will broaden and shorten. This causes its electrical resistance to decrease from end to end. However, when the conductor is stretched, it will become narrower and longer. This causes its electrical resistance to increase from end to end. These changes in electrical resistance can be measured, and therefore the stress can be inferred. This is how a strain gauge works, which, as noted above, tends to be the most accurate version of a torque sensor. These strain gauges are typically applied to a rotating shaft or axle.

Magneto-elastic sensors are also used. In the case of magneto-elastic sensors, the magnetic susceptibility of a material changes due to mechanical stress being introduced. This also allows the strain or stress to be inferred, since the magnetism is directly related to the amount of force being applied. This makes them accurate enough for the purpose of functioning as a torque transducer. Undoubtedly, torque measurement transducers will continue to develop and advance, making them more portable, less costly, and more accurate as they continue to be developed.