To better achieve the performance of the servo motor, it is necessary to understand some characteristics of the servo motor.

Noise and unstable users When using servo motors in certain machinery, there are often phenomena such as excessive noise and an unstable load of the motor drive. When this problem occurs, the first reaction of many users is the poor quality of the servo motor. Because sometimes stepper motors or variable frequency motors are used to drive loads, noise and instability are much smaller. On the surface, it is indeed the cause of the servo motor, but after careful analysis of the working principle of the servo motor, we will find that this conclusion is completely wrong.

The AC servo system includes a servo drive, a servo motor, and a feedback sensor (generally the servo motor is equipped with an optical polarizer). All these components operate in a closed-loop control system: the drive receives parameter information from the outside, then sends a certain current to the motor, converts the motor into torque to drive the load, the load moves or accelerates or decelerates according to its characteristics, and the sensor measures For the position of the load, the drive compares the set information value with the actual position value. By changing the motor current, the actual position value is consistent with the set information value. When the speed change is caused by a sudden change in load, the polarizer will respond to the servo drive immediately after knowing the speed change. The drive will change the current value provided to the servo motor to meet the load change and return to the set speed.

The AC servo system is a fully closed-loop system with a very high response. The time lag between load fluctuation and speed is very fast. At this time, the transmission time of the mechanical connection device is indeed limited. Check the errors and alarm numbers on the drive, and then check the manual. If there is no alarm, the driver is naturally faulty. Of course, the servo may not be faulty, but the error of the control signal causes the servo system to not move. In addition to checking the errors and alarm numbers on the servo drive, and then looking for the manual, sometimes the most direct judgment method is a replacement, such as X-axis and Z-axis servo replacement (the same model can be used). or modify the parameters, such as locking the X-axis and not letting the system detect the X-axis. It should be noted that the X-axis and Z-axis are interchanged. Even if the model is the same, the imported equipment may have problems due to different loads and parameters.

Of course, if it is a domestic device, the servo parameters are usually not adjusted for use, and there is generally no problem. Pay attention to whether the power torque of the X-axis and Z-axis motors is the same, whether the motor wire rod is directly connected, and the electronic gear reduction ratio. Several questions about the AC servo motor: related, synchronous speed n1=60f/2p, asynchronous machine and slip rate s, nn1=(1-s)n1, the synchronous machine is a pole-pair number. The definition of the field weakening speed in the control is determined by the driver. The rated speed can be determined by several aspects: the reverse potential of the synchronous servo, the alternating frequency of the drive current allowed by the core material of the motor, the maximum power of the motor at the rated torque, and the maximum temperature rise. , The most important is the reverse potential; asynchronous motors are mainly limited by the maximum frequency allowed by the material and the logarithm of the extreme value. The definition of rated speed is determined by the electromechanical characteristics of the motor itself. Answer: AC servo usually refers to the servo-driven by a sine wave, and the brushless drive is equivalent to 6 rectifiers.