The meaning of low inertia and high inertia of servo motor
Moment of inertia = radius of rotation * quality
The low inertia is that the motor is relatively flat and the spindle inertia is small. When the motor is repeatedly operated with high frequency, the inertia is small and the heat is small. Therefore, low inertia motors are suitable for high frequency reciprocating motion use. But the general torque is relatively small. High inertia servo motors are relatively large and have large torques, which are suitable for high torque but not very fast reciprocating motion. Because of the high speed movement to stop,the servo driver has to generate a large reverse drive voltage to stop this large inertia, and the heat is very large.
Inertia is a measure of the inertia of a rigid body rotating around an axis. The moment of inertia is a physical quantity that characterizes the rotational inertia of a rigid body. It is related to the mass and quality of the rigid body relative to the distribution of the shaft.(Rigid body refers to an object that does not change under ideal conditions). When it is selected, it encounters motor inertia, which is also an important indicator of servo motor. It refers to the servo motor rotor itself inertia ,which is very important for the acceleration and deceleration of the motor. If the inertia is not well matched, the motor's motion will be very unstable.
Generally speaking, the motor with small inertia has good braking performance, and the reaction of starting and accelerating stops is fast, and the high-speed reciprocating property is good. It is suitable for some light load and high-speed positioning occasions, such as some straight-line high-speed setting organization. Medium and large inertia motors are suitable for applications with high loads and high stability requirements, such as some circular motion mechanisms and some machine tool industries.
If the load is large or the acceleration characteristics are relatively large, and the motor with small inertia is selected, the motor shaft may be damaged too much. The choice should be based on the size of the load, the magnitude of the acceleration, etc.to choose, the general selection manual has the relevant energy calculation formula.
The servo motor driver responds to the servo motor. The optimum value is the ratio of the load inertia to the motor rotor inertia. The maximum can not exceed five times. Through the design of the mechanical transmission, you can make the ratio of load inertia to motor rotor inertia close to one or less. When the load inertia is really large, the mechanical design cannot make the ratio of the load inertia to the motor rotor inertia less than five times.A motor with a large rotor inertia is called a so-called large inertia motor. To use a motor with a large inertia, the servo drive capacity should be larger to achieve a certain response.