Servo motor selection calculation methods

Changzhou Finer motor co.,Ltd

    The servo motor refers to the engine operating in the servo system, which is an indirect transmission device for subsidized motors. The servo motor developed by our company can control the speed, the position accuracy is very accurate, and the voltage signal can be converted into torque and speed to drive the object. The servo motor rotor is controlled by the input signal and can be quickly reacted. In the automatic control system, it is used as an execution component, and has the characteristics of small mechanical and electrical time constant and high linearity. Corner shift or angle speed output. It is divided into two categories: DC and AC servo motor. The main feature is that when the signal voltage is zero, there is no self -rotation, and the speed decreases at a constant speed as the torque increases.

First, Calculation method:
1. Confirmation of speed and coder resolution.

2. Calculation of the loading torque on the motor shaft and the calculation of the increase and subtraction torque.

3. Calculate the load inertia, the matching of inertia, so that the FINER servo motor can be used as an example. Some products can reach 50 times, but the actually smaller the better, so that the accuracy and response speed is good.

4. Calculation and selection of regeneration resistance. For servo, generally 2kW is more than 2KW, and external configuration is required.

5. Cable selection, encoder and cable double bend.

Second, Basic calculation of the power of the servo motor:

Output power p = 0.1047*n*t

In the formula N is the rotation speed, T is torque. The rotation speed is basically 3000 rpm.

Torque T = R*M*9.8

In the formula, R is a shaft radius, and M is the weight of the object.

Third,Select points for the power of the servo motor:

The power of the motor should be selected according to the power required by the production machinery, so as to make the motor run under the rated load as much as possible. If the power of the motor is selected too small, the "small horse big car" phenomenon will occur, causing the electric motor to overload for a long time, causing the insulation to damage it due to fever. Even the motor was burned.

If the power of the motor is selected too large, the "big horse car" phenomenon will occur. The output mechanical power cannot be fully utilized, and the power factor and efficiency are not high, which is not only unfavorable to users and grids. It also causes waste of electricity.

Fourth, the actual selection method of servo motor power:

1. To choose the power of the motor correctly, the following calculations must be calculated or compared:

Power P = F*V /1000 (P = Calculating power KW, F = required pulling force n, V = working line speed m /s)

2. For constant load continuous working methods, you can calculate the power required for the electrical motor:

P1 (KW): P = P/N1N2

In the formula, N1 is the efficiency of production machinery; N2 is the efficiency of motor, that is, transmission efficiency.

The power P1 found according to this formula is not necessarily the same as product power. Therefore, the rated power of the selected motor shall be equal to or slightly greater than the power obtained.

Fifth, need to consider torque (torque), motor power and torque calculation formula:

That is torque T = 9550 P/N

In the formula P -power, KW; N -motor rated speed, R/min; T -torque, nm.

The output torque of the motor must be greater than the torque required for work machinery, and generally requires a safety factor.

Mechanical Power Formula: P = T*N/97500

In the formula P: power unit W; t: torque, unit gram/cm; n: speed, unit R/min.

For more information, please contact FINER engineers. Thank you.