Electric torque is undoubtedly one of the main characteristics of an electric motor. Knowing how to calculate the torque of a motor is essential to perform the correct sizing of the electric motor. In this article, the World of Electrical explains what torque is and how to calculate the electrical torque of an engine. Come on!
What is torque?
Torque, also known as moment of force, is a force applied to a body that tends to rotate this body. Torque is a vector quantity, that is, it has modulus, direction and direction, and can be calculated by means of the vector product between force and distance. According to the International System, the unit of measurement for torque is Newton times meter (Nm).
We need to understand that whenever a given force has applied some distance from the rotation axis of a body, that body will be subject to rotation, that is, whenever we want to make a body rotate around some point, we must exert a torque on this body.
Torque x Work
When we talk about the electric torque of an engine, it is important to highlight that the electric motor, in addition to torque, also generates work, although the units of measures and formulas are the same, torque and work are different quantities! The main difference is that the torque on the engine exists even if the engine is not running.
Torque x Power
It is important to note that torque and power are not the same, in fact, torque and power are different and complementary quantities. An example that we can cite is the power generated by an electric motor because the electric power is directly proportional to the torque generated over a given rotation speed. For the same speed of rotation, the greater the power, the greater the torque supplied.
Torque x Speed
Torque and speed are completely different quantities, but they are quantities that are related. A good example is speed reducers, which through gear systems have the ability to increase torque and reduce engine rotation speed.
The torque variation caused by the speed reducers is inversely proportional to the variation caused in the rotation speed. The greater the reduction in speed, the greater the resulting torque, that is, the lower the speed of the motor, the greater the torque of the same motor.
In this case, it is very important to note that the electrical power does not increase because of the speed reducer, in fact, the opposite occurs, as it suffers a reduction or loss, which is determined by the internal efficiency or efficiency of the reducer. Reducers that have a higher efficiency are able to convert the power to which they are subjected to more torque, considering the same reduction ratio.
Torque: How to calculate?
As mentioned earlier, torque is the ratio of distance multiplied by force. For this, we will calculate the torque of an electric induction motor, capable of producing a force of 80N at a distance of 0.25m from the center of its axis.
In this case, the calculation is very simple! As we already have all the necessary values to make the calculation, just replace them directly in the torque formula. After replacing the values, just multiply, obtaining a torque of 2,000 Nm, as shown in the example below.
If you want to learn much more about electric motors, we have below a video from the Mundo da Elétrica channel that explains in detail what an electric motor is, the characteristics of an electric motor and how an electric motor works. It is worth checking!