How to measure Torque?

How to measure Torque?
30.08.2023
In this article, you will learn about signal processing in sufficient detail to:

Understand what torque at the highest level is
Learn how to measure torque
See how torque measurement works in DAQ applications

What is torque?

If you remember in physics class, force is an input that changes the motion of an object over time. For example, a simple linear force can push (or pull) mass in a stationary state, changing its velocity by accelerating it over time. Torque is the force that causes an object to rotate around an axis of rotation. Thus, torque is a "torsional force," otherwise known as a rotational force. The most obvious example of torque is the drive shaft in your car. The amount of torque that dynamically

Why do we need to measure torque?

Measuring the mechanical torque of the spindle is essential when designing, commissioning and troubleshooting all types of machines. Knowing the true mechanical torque of an axis, propeller, or other rotating part is the only way to know that it is meeting its specifications. In some applications, it is important to always know what the torque is to guard against potentially dangerous excess torque that could lead to system damage or failure. Torque measurement is part

The reaction torque sensor measures static or non-rotational torque. A good example of a reactive torque sensor is the torque wrench. This tool is used to ensure that the correct amount of torque is applied to bolts, nuts or other screws. The base of the wrench is capable of adjusting the desired amount of torque, and when the operator applies force, an audible click is heard when the correct torque is reached. They are often referred to as force wrenches and they provide several 

Reactive torque sensors use quartz based piezoelectric sensors or strain gauge sensors to measure torque. There are many types and variations of force wrenches and force screwdrivers.

Torque sensor (dynamic)

A torque sensor is a converter that converts torque into output that we can measure, display, analyze and store. Rotary torque converter is used for engine torque test, internal combustion engine test, electric motor test, drive shaft, turbine, cheek test

When the shaft is rotated by the motor, it twists very slightly. Due to the hardness of the steel, torsion cannot be seen with the naked eye but can be detected by strain measuring devices linked to the shaft. The arrangement of the four gauges includes a Wheatstone bridge, whose output is balanced and adjusted using a torque measurement system. The output of this strain gauge can be wired directly (if possible) or measured wirelessly to torque measurement or DAQ (data acquisition).

Inside the torque sensor itself, the outputs from the Strain gage sensors mounted on the shaft are sent to the electronics using slip rings (Strain gage sensors must be powered). In addition, a brushless or induction sensor connection can be used, allowing for higher speeds and less physical wear, resulting in less maintenance in the long run. Angle and RPM can also be measured non-contact.

Dewesoft's DAQ system is ideal for measuring all physical parameters, including

DewesoftX torsion and rotational vibration test output

Fixed installed torque measurement system

In the system shown above, a torque sensor is installed between the engine and brake, using couplings on each side. The shaft running through the sensor is equipped with a strain gauge sensor to measure the torsional force on the shaft. The output of this signal is harmonized and sent to the DAQ (data acquisition) measurement system, or simply to a digital display or alarm system if monitoring is required but no data is recorded.

Kistler's sensors are compatible with DewesoftX DAQ software and can therefore be integrated into DAQ systems of any size, from one channel to hundreds of distribution channels.

Ordinal analysis application

Torsional vibration is the cause of damage on the axes of rotation. Rotational and torsional vibration analysis is an important tool for troubleshooting shafts, crankshafts, gears in automotive, industrial and power generation applications.

What is torsional vibration?

Torsional oscillation is the angular oscillation of an object, typically a longitudinal axis th

What is rotational vibration?

Rotational vibration is simply a dynamic component of rotational speed. If we measure the speed of rotation of the shaft with high accuracy, we will notice that we have a high deviation in the rotational speed in some zones during the run. This is caused by angular oscillations that surpass the axis' natural angular frequency. It is calculated by cutting the DC component of the rotational speed or rotation angle. The degree of torsional vibration is affected by a number of parameters, such as material properties and operating conditions.

The DewesoftX torsional vibration solution automatically calculates a number of different parameters:

Rotation angle: filtered angle value of vibration
Rotational velocity: filtered velocity vibration value
Torsion angle: The dynamic torsion angle is the angular difference between sensor 1 and sensor 2
Torsional velocity: difference in velocity angle from sensor 1 to sensor 2
X-axis reference angle: reference angle, always from 0 to 360 and can be used as a reference in an angle-based X-Y diagram
Frequency: in units of RPM.
The calculation can be done online