How to measure the rotary torque and power of a motor?

When the motor rotates and generates torque, the shaft body will be subjected to torsional strain. Based on this, the strain gauge electrical measurement technology is used to form a strain bridge on the elastic shaft, and the electrical signal of the elastic shaft torsion can be measured by supplying power to the strain bridge. After the strain signal is amplified, it undergoes pressure/frequency conversion to become a frequency signal proportional to the torsional strain.

When we getting the motor dynamic torque, how to measure the motor output power?

According to the relationship between the motor power, torque and speed:

M=9550P/n

-M: Dynamic torque (N.m)

-P: Output power (Kw)

-n: Motor rotating speed (r/min)

We can use a rotary encoder to measure the motor rotating speed. Then we can calculate the motor output power according above formula. When the motor is no load running, the M is almost 0Nm, then the output power is about 0w.

Based above, we can integrate the rotary encoder and the dynamic torque sensor in one sensor, and through the corresponding internal computing circuit, we can use it to measure the motor dynamic torque, speed and power 3 values directly. Our CALTSENSOR DYN200 series dynamic torque sensor is just such a sensor, it can measure the dynamic torque, speed and power, and also with a LED to display these values on the sensor.