Rotary Torque Sensors Support

Spec Sheets

Application Questions?

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Rotary Torque FAQ
Does the use of strain gauges offer any advantages over other elements such as magnetic or capacitive?
Strain gauge types provide long-term stability, wider temperature-range operation, and are more immune to vibrations when compared to other technologies.
What is the usage of the encoder and what is the output type?
Encoders can be used to measure angle and speed. The output is a ttl type signal out looking like a square wave. There are two outputs available from our encoders, one waveform leading the other. This can be used to tell which direction the sensor is rotating.
How do you mount a rotary torque sensor (aka dynamic torque sensor)?
We offer square drive and hex drive. Also, for shaft-to shaft, the use of couplings is recommended.
When designing a system with a stepper or servo motor, what type of sensor do you recommend?
For stepper motor we recommend reaction torque sensor which can be mounted on one end of the torque sensor. For a servo motor, either reaction or rotary torque sensor can be used. Either one can be used based on the size of the motor.
At what speed should we consider using stiff couplings over flexible couplings?
Stiff couplings are recommended for high dynamic measurements to avoid damping and deformation during measurement. For lower capacity torque, flexible coupling is recommended.
Can your torque sensor measure static torque or does it require rotation?
We can measure static and reaction torque.
Are there any environments that the sensor is not suited for?
The sensor is not suited for submersible or contaminated environments. The sensor is also not suited for environments with high amounts of vibrations or noise pollution.
How many pulses do I get per revolution?
360 degree pulses.
How can a rotary torque sensor be damaged from normal use (other than dropping it)? Enough to put it out of calibration.
High torque startups and shock-type loads, misalignment due to improper mounting as well as wear and tear in slip ring type. Also, exceeding the safe overload limit. If you notice your sensor is not performing as specified, FUTEK can help you with dynamic torque calibration sensors services.
How do you know when the contacting internal components (brushes) wear out? What is the life expectancy?
For Slip ring type at 3000 RPM they are rated for 100 million cycles. Also when you notice intermittent output or display.
How does temperature effect sensor?
Our sensors are temperature compensated and further details can be found for each model on the respective spec sheets (on our website).
What is the accuracy of the sensors?
The accuracy of each model will vary so we highly recommend that you reference our specification sheets.
How much is the life of the torque sensor reduced by high RPM?
Non-contact type rotary torque sensors are less sensitive to this issue however bearings may need replacement. For slip ring type rotary torque sensors such as our TRS300 at 3000 RPM the slip ring is rated for 100 million cycles while increasing the RPM to 6000 RPM decreases the life expectancy to 50 million cycles. For specific life cycle questions please contact us directly.
Can you offer some guidelines on brush and brushless rotary torque sensors?
The housing and rotating shaft have direct physical contact through brushes, which are mounted to the housing, and the slip ring, which is mounted to the rotating shaft. However, with brushless, which FUTEK refers to as non-contact, the power supply and signal are transmitted through transformers. Also, non-contact supports higher speeds and requires less maintenance.
If you use flexible couplings how misalignment will be avoided?
Flexible couplings are designed to compensate or eliminate any extraneous load or moments due to misalignment, therefore avoiding premature failure.
Is output signal linear?
Yes, Please refer to spec sheets per selected models.
Is it possible to use needle bearings in a extremely accurate measurement?
Needle bearings are known for tolerating higher radial loads and they are larger in size and not suitable for compact packages.
Can all plc be used with your rotary sensors or have some limitations?
Sensors with 5VDC output option can be used with most PLCs.
Can multiple rotary sensors be used at the same time?
Yes. Several applications are illustrated in our website showing monitoring/analyzing Load simultaneously. Please send more detail and a technical adviser will contact you with proper solution.
Do you have thru-feed model?
We offer a variety reaction torque with thru hole as standard products. Also, we offer custom made rotary torque sensor with thru hole.
Do your rotary sensors have NI drivers for lab view?
FUTEK offers mV/V, VDC and USB digital output which can be integrated out with NI hardware and LabVIEW software.
For a motoring or load absorbing dynamometer, is a pedestal base mount required?
Yes, pedestal base with flexible couplings are recommended.

How to choose a Torque Sensor for your application?

 A question that we frequently hear is: “What is the right sensor for my application?” The reason why it gets asked so often is that it can be tricky to navigate the various sensor offerings on the market. So, be it a compact torque sensor or a high capacity torque sensors , make sure to follow the steps below for adequate torque sensor sizing.


reaction torsion sensor has two mounting flanges (flange-to-flange sensor). One face is fixed to the ground or a rigid structural member and the other to the rotating shaft or rotary element. Rotation generates shear forces between the flanges, which is captured by the foil strain gauges bonded to the sensor beams and transduced into electrical current by the Wheatstone bridge.


Rotary Torque Sensors are designed to measure torque of a rotating shaft. Thus, it is necessary to transfer power to the strain gauge bridge, as well as a means to receive the signal from the rotating torque meter or shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Optionally, sensors can also embed encoder for angle or speed measurement

 how to measure torque of a motor rotary torque transducer sensor working principle digital compact torque sensor
Fig. 6: Rotary Compact Torque Sensor and its internal components. Source: FUTEK YouTube Webinar.




To help you select your torque sensor, FUTEK developed an easy to follow, 4-Steps guide. Here is a glimpse to help you narrow down your choices. Check out our “How to choose a Torque Sensor” complete guide for further information.

  • Step 1: Understand your application and what you want to measure or control. Firstly, understand your application and define the type of torque you want to measure — reaction torque or rotary torque? Also, what is the environment (temperature, pressure, humidity). The application may require underwater torque sensors accompanied by a pressure transducer.
  • Step 2Define the sensor mounting characteristics and its assembly. How will you be mounting the sensor? (Flange to flange, square drive, shaft to shaft, hex drive, etc.) Will you be using this clockwise, counterclockwise, or both?
  • Step 3Define your minimum and maximum capacity and key requirements. Be sure to select the capacity over the maximum operating torque and determine all extraneous load (side loads or off-center loads) and moments prior to selecting the capacity. Also, what is your max RPM required? Do you need to measure speed and angle position?
  • Step 4: Define the type of output your application requires. Some sensors outputs a mV/V signal, which can be paired with an amplifier for up to ±10VDC, while other non-contact rotational sensors will provide ±5VDC output. So, if your PLC or DAQ requires analog output, digital output or serial communication, you will need a torque sensor amplifier or signal conditioner. Make sure to select the right strain gage amplifier as well as calibrate the entire measurement system (sensor + signal conditioner). This turnkey solution translates into more compatibility and accuracy of the entire torque measurement system.
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