Torque Sensor Selection Guide

• Torques sensors are transducers which converts torsional mechanical inputs into electrical output signals.
• It is strain Gauge based sensor.
• Torque sensor usually feature four strain gauges in a Wheatstone bridge configuration, which is an electrical circuit that balances two legs of a bridge circuit.

• The torque being measured deforms the strain gauge in this type of torque sensor, and the deformation is measured as a change in electrical signal.
• There are two different types of torque sensors

1) Reaction torque transducers:

• A torque sensor that measures static torque.
• It is used in the applications where angular motion is limited and in-line torque measurements are required
• Examples: Used to measure the torque applied to vehicle control elements, Acquisition of breakage moments on screw caps ,torque calibrator etc
• It offers long term reliability as they have non-moving parts

2) Rotary torque transducers:

•  A torque sensor that measures dynamic torque.
•  It is used in the applications where the torque transducer must rotate when attached to a spinning shaft.
• Examples :Used to measure drag torque of motors and pump, to measure Nut Runner Force/Torque , for Torque/Motor Test Stand  etc.

NOTE:

• Both the above sensors requires alteration of shaft to connect the sensor in between the prime mover and the load.
•  Sensor is placed between the prime mover and the load.
• Coupling is required to connect the sensor.
• When alteration of shaft is not possible then Telemetry system can be adopted.

Telemetry system

• It is based on strain gauge principle.
• It transfers output signal wirelessly through transmitter and receiver is connected to the display.
• In this system wheat stone bridge/strain gauge is attached on the shaft to convert the shaft itself into a torque sensor.
• Alteration of shaft , coupling is not required.