Variable Speed Drive Characterization: Review of Measurement Techniques and Future Trends

Table 11

Torque measurement techniques.

Rotating system
Strain sensitive	Strain gauges and similar	Strain gauges
		Torsion bars with different cross section
		Cruciform cross section with linear strain gauges glued on bending beams.
	Magnetostrictive effects	Coil systems with induced eddy current in the shaft
		Coil systems with change of permeability of the shaft
Torque angle sensitive	Toothed wheels, slotted collars, stamped rings	Phase detection by magnetic pickups
		Coils systems with slotted collars
		Coil systems with torsional variable differential transformer
		Encoder disks with Led-photocell arrangement
	Transmission to linear displacement by lever	Transmission by lever to inductive differential gap sensor
		Transmission to string vibration transducer
		Transmission to linear variable differential transformer
Reaction system
Strain sensitive	Strain gauge	Torsion bars with different cross sections
		Transmission to strain sensitive bending beams or platforms
Force or displacement sensitive	Strain gauges, piezoelectrics, and others	Cantilever with different kind of force and displacement transducers