Communication And Control Distance Between VSD And Motor
You will get efficient and thoughtful service from .
The distance between the VSD and the motor can be divided into three cases: long distance, medium distance and near distance. 20m or less is near distance, 20-100m is medium distance and more than 100m is long distance.
As the output voltage waveform of the VSD is not sinusoidal, the waveform contains a large number of harmonic components, the high harmonics will increase the output current of the VSD, which makes the motor winding heat up, generates vibration and noise, accelerates insulation aging, and may damage the motor; at the same time, the harmonics of various frequencies will generate radio interference, which may also lead to other equipment misoperation.
Therefore, it is good to close connect the VSD and the motor. However, due to the space limitation of the production site, there is certain distance between the VSD and the motor.
1. If the distance between the VSD and the motor is within 20m, the VSD can be connected with the motor directly; for distance from 20m to 100m, we need to adjust the carrier frequency of the VSD to reduce the spectrum and interference; and for distance more than 100m, not only need to moderately reduce the carrier frequency, but also need to install an output AC reactor.
2. In the highly automated factory, all the control equipment can be monitored in the central control room, the signal of the VSD system is also sent to the central control room, if VSD is installed in central control room, the general console and the VSD can be directly connected through the 0-5/10V voltage signal and some switching signals. However, the electromagnetic radiation of the high-frequency switching signal of the VSD will produce some interference to the weak current control signal, so it is not necessary to install the VSD in central control room. If there’s a little distance between the VSD and the central control room, we need to connect 4-20mA current signal and some switch; if the distance is farther, we can use RS485 serial communication to connect; if we want to extend the distance further, we can use communication intermediate relay to control 1km distance; and fiber optic connector can control 23km distance. With the communication cable connection, it is easy to realize multi-drive control system, which can meet the requirements of master/slave and synchronous control. This will greatly improve the data conversion rate. The extension of the distance between the central control room and the VSD cabinet will help to shorten the distance between the VSD and the motor, so as to improve the system performance with a more reasonable layout.
In short, when installing the VSD, we need to consider the distance between the central control room, the VSD and the motor to minimize the impact of harmonics and improve the control stability.
If you want to learn more, please visit our website.
If you are looking for more details, kindly visit medical electronics pcb assembly.