A torque sensor measures the amount of rotational force in mechanical components. The measurements are transmitted to operators or control systems in order for machinery to function properly and engines to work correctly. In the sensor, a metal spring is attached to a strain gauge, which is affected by the torque the sensor is exposed to. Voltage is then generated based on how much torque there is. A torque transducer is usually classified as either a rotary or reaction sensor and its function is dependent on how much torque it can handle, what kind of load and drives it is built for, and the load it can tolerate when a machine or engine is started.
The reaction type of torque sensor is stationary and requires a way to attach electronics and electrical connections to the moving components being measured. More stable systems have a rotary torque sensor, in which the sensor electronics rotate with the sensor. Attaching a cable to a rotating sensor is difficult, so engineers have added digital electronics that can turn, attached slip rings, or have included radio transmitters. Strain gauge amplifiers and signal converters have also been integrated into rotating components and more complex designs even have analog to digital as well as digital to analog converters.
Measurement errors caused by the force of mechanical components affect the accuracy of a torque sensor attached in-line. A sensor that rotates while measuring can be a solution to this problem. To prevent the sensor from being damaged, the maximum torque the sensor can frequently handle must be known. The type of load put on the sensor can vary greatly depending on where it is used. Load forces of fan or blower, conveyor or crane, to crushing equipment and crankshafts of automobile engines are rated in a scale to categorize each torque sensor.
The type of engine the sensor can handle depends on whether it is rated for a four, six, or eight-cylinder engine or a gas or diesel system. A torque sensor can handle a certain drive force created by the particular engine type. In a pump, a torquemeter can detect changes in flow, while it can measure the amount of force a stamping machine has when putting a cap on a bottle. A torque sensor can also be attached to a conveyor motor to help control tension. It is also used in electronic screwdrivers as well as in exercise and testing machines.