Torque transducer Kistler 500

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A torque sensor, transducer, or meter gauges rotating system torques such as engine crankshafts, gearboxes, transmissions, rotors, bicycle cranks, and cap torque testers. Static torque is straightforward to measure, but dynamic torque, which requires transferring effects (electric or magnetic) from measured shafts to static systems, is more challenging. One way to do this is by applying permanent magnetic domains on the shaft, whose magnetic characteristics vary with applied torque and can be detected by non-contact sensors. Magnetoelastic torque sensors are used in vehicle applications like racecars, automobiles, aircraft, and hovercraft. Traditional methods use strain gauges attached to rotating shafts, requiring power for the gauge bridge and signal reception from the rotating shaft via slip rings, wireless telemetry, or rotary transformers. Newer torque transducers integrate conditioning electronics and A/D converters on the rotating shaft, with stator electronics reading digital signals and outputting high-level analog signals. SAW devices attached to shafts and remotely interrogated are a recent development, with automotive use anticipated. Twist angle or phase shift measurement is another technique used in engines like Allison T56. For right-angle gearboxes, axial input stress can be related to output torque after calibration. Input stress is measured via strain gauge on the pinion bearing housing, and output torque with a static torque meter.