Dynamic Torque Measurement [Application Note]
Published by Cyndi Rude – September 18, 2015
Rotary power sources and absorbers have discrete poles and/or pistons and/or gear meshes, etc. As a result, they developand absorb torque in a pulsating rather than a smooth manner. Furthermore, a driveline consists of several inertias and torsion springs which resonate at one or more frequencies. Finally, even when running at “constant” average speed, every drive has some angular acceleration which, in combination with shaft inertias,generate dynamic inertia torques.
Thus, real world driveline torque is never constant. Instead,it consists of an average torque with superimposed oscillatory components. The oscillatory components can excite driveline resonance(s). These effects are exacerbated during transient load conditions. Accurate measurement and/or control of dynamic driveline torque requires an understanding of how the Torquemeter and other drive components interact. This note
provides insight into those interactions from theoretical and practical viewpoints.