A magnetostrictive torque transducer measures rotating torque by utilizing the magnetostrictive effect, which is the property of certain materials to change their shape or dimensions when subjected to a magnetic field. The transducer is designed to convert the applied torque into a measurable physical deformation using this principle. Here's how it works:
Construction: A typical magnetostrictive torque transducer consists of a torsion rod or shaft made of a magnetostrictive material. This material undergoes slight changes in its dimensions when subjected to a magnetic field.
Sensor Assembly: The torsion rod is surrounded by a magnetic field generation assembly. This assembly typically consists of a set of coils, a magnet, and a magnetic circuit to focus the magnetic field onto the torsion rod.
Magnetic Field Application: When torque is applied to the transducer's input shaft, the torsion rod undergoes a slight twist due to the applied torque. This twist causes changes in the magnetic field within the torsion rod.
Sensing Mechanism: The magnetic field generation assembly also includes a sensing mechanism that detects the changes in the magnetic field within the torsion rod. This sensing mechanism could be based on various principles, such as magnetic induction or Hall effect sensors.
Measurement: As the torsion rod twists due to the applied torque, the magnetic field changes within the rod, and this change is detected by the sensing mechanism. The sensing mechanism converts these changes into electrical signals, which are proportional to the applied torque.
Output: The electrical signals from the sensing mechanism are then processed by electronics within the transducer to provide a usable torque measurement as an output. This output can be in various forms, such as analog voltage, current, or digital data, depending on the specific design and application of the transducer.
The advantage of magnetostrictive torque transducers is that they can provide precise and accurate torque measurements without direct contact with the rotating shaft. This non-contact measurement makes them suitable for various applications, including test and measurement, quality control, and industrial process monitoring where precise torque measurement is required.