Sensor Technology has launched a new range of non-contact torque sensors based on a full four-element strain gauge bridge design, complementing its existing non-contact sensors that use surface acoustic wave (SAW) detection.
Designated the TorqSense SGR510/520 series, the new units have a 250% over-range reading capacity, allowing sudden spikes in torque to be measured and recorded accurately. The design also compensates for any extraneous forces, such as bending moments, inadvertently applied to the sensor, improves sensitivity and has a wide temperature tolerance.
The bridge is essentially four strain gauges glued onto the shaft in a square formation set at 45deg to the axis of rotation. Thus, when torque is applied to the shaft, two gauges are stretched into tension, and two go into compression.
A rotor mounted ultra-miniature microcontroller, powered by an inductive coil, measures the differential values in each strain gauge and transmits them back to the stator digitally via the same coil. The SGR510/520 series transducers then use state of the art strain gauge signal conditioning techniques to provide a high bandwidth, low-cost torque measuring solution with high over-range and overload capabilities.
The measuring range of the SGR series is 1Nm to 500Nm (with models up to 13000Nm available shortly), accurate to +/-0.1% and with a resolution to +/-0.01% of the transducer’s full scale.