A3-PL and A3-Lite

How to use an Active Sensor Kit?

  • Installation: Simply mount the Sensing Module next to your shaft with a small air gap
  • Initialisation: After the execution of an automatic System initialisation (zero-offset) Torque measurements can be taken immediately
  • Principle: Magnetic fields emanating from and received by the Sensing Module are analysed by the Sensor Electronic to determine the applied mechanical stress levels in the shaft
  • Output Signal: The Sensor System supplies a linear output signal as an analogue voltage (0-5V). Some Sensor Kits provide also Serial Digital (USB) interface

Advantages of the Active Sensor over other torque sensors

  • No changes: Use the shaft (Test-Object) “as is” without having to alter it
  • Easy: Applying the Torque Sensor is as simple as mounting it next to the shaft
  • Reusable: The Active Sensor can be re-used in number of different applications
  • Affordable: Save costs by leaving your application unchanged

What shafts (Test-Objects) can be used?

  • Ferromagnetic: A permanent magnet must be attracted to the shaft material (alloy used)
  • Hardened: The measurement location on the shaft should be hardened (>48 HRc)
  • Alloys: Best performance are achieved when Ni and Cr are included in the alloy
  • Accuracy: The used alloy will affect measurement quality. Consult us first

What does Non-Contact Measurement mean?

    • Not touching: The Sensing Module does NOT have to touch the Test Object (shaft)
    • Airgap: air-gap (sensor – shaft) can range from 0 to >3 mm
    • 5 to 1mm: Best performance will be achieved when the air-gap is 0.5 mm to 1 mm
    • Constant distance: While taking measurements the air-gap should not change  (otherwise changes in the output signal offset)

What is the maximum shaft speed?

  • No limit:  There is no upper limit for the shaft speed
  • Static: Measurements can also be taken from a static (non-rotating) shaft

What are the achievable measurement performances?

  • Ideal: The achievable Torque measurement performances can be very high
  • Optimal design: Everything depends on how optimal the Test-Object (shaft) design may be
  • Used alloy (incl. Ni and Cr), applied hardening, constant air-gap, degaussed shaft
  • Overload detection: When too many design compromises must be made the Torque Sensor still can be used as an overload detector

What shaft diameter can be used?

  • Diameter range: From Ø3mm to ∞
  • Minimum diameter: <Ø3mm is possible with special precautions, contact us first
  • Maximum diameter: There is no upper limit

What is the Torque measurement range?

Guidance: The shaft diameter (i.e. the physical strength) determines its optimal measurement range

Influencing Factors: The shaft diameter, material and applied hardening defines the Torque measurement range

Torsion Stress: Ideally, the torsion stress in the shaft at maximum load will be in the area of 40 to   (which is the mechanical stress at the surface of the Test-Object, measured in Mega Pascal)

What will be the Measurement Hysteresis?

  • Perfect measurements require a perfect alloy: The used alloy, the applied hardening process, and the measurement range defines what the measurement hysteresis will be
    • With 45CrNiMo16 and other similar materials the measurement hysteresis
      can be very small (< 1% of FS)
    • C45 will provide very poor performance and at best can be used as an Overload Torque Sensor only
  • Hysteresis cancellation: Beginning of 2018, some of the Active Sensors include an effective and novel hysteresis-compensation. Contact us for more details

Does the Shaft have to be demagnetised?

If in doubt: YES: Demagnetisation of the Test-Object is only required if it has come in contact with a strong magnet

Offset Shifts: Accidentally embedded magnetic fields will cause rhythmic signal offset shifts when the shaft is rotating

Not always possible: In some cases it may be difficult to demagnetise large diameter and heavy shafts. In this case the Sensor output signal has to be filtered over one or more shaft revolutions (this feature is part of the Sensor electronic)