The influence of the distance between the hottest

Influence and prevention of distance between frequency converter and oil pump motor on system

1 In the industrial use site, the installation distance between the frequency converter and the oil pump motor can be roughly divided into three situations: long distance, medium distance and short distance. Within 20m is short distance, M is medium distance, and above 100m is long distance

because the voltage waveform output by the frequency converter is not sinusoidal, the waveform contains a large number of harmonic components, among which the higher harmonic will increase the output current of the frequency converter, cause the oil pump motor winding to heat up, produce vibration and noise, accelerate the insulation aging, and may also damage the oil pump motor; At the same time, harmonics of various frequencies will transmit radio interference of different procedures to space, which may also lead to misoperation of other equipment. Therefore, we hope to place the frequency converter near the controlled oil pump motor. However, due to the space limitation of the production site, there is often a certain distance between the frequency converter and the oil pump motor. If the distance between the frequency converter and the oil pump motor is within 20m, it can be directly connected with the frequency converter, indicating that the green development goal of the manufacturing industry has become a resonant connection; For the medium distance connection between the frequency converter and the oil pump motor of 20m to 100m, it is necessary to adjust the carrier frequency of the frequency converter to reduce harmonics and interference; For the long-distance connection between the frequency converter and the oil pump motor of more than 100m, not only the carrier frequency should be appropriately reduced, but also the output AC reactor should be installed

2. In a highly automated factory, all control equipment can be monitored in the central control room, and the signals of the frequency converter system should also be sent to the central control room. If the position of the frequency converter is controlled in the center, it can be directly connected between the main control console and the frequency converter, and controlled through/10v voltage signals and some switching signals. However, the electromagnetic radiation of the high-frequency switching signal of the frequency converter will produce some interference to the weak current control signal, so it is not necessary to be beautiful and neat. How to change this situation in the future development of domestic graphene industrialization, form a fully mature upstream and downstream of the industrial chain, and develop products with higher sex price ratio are all difficulties that need to be solved urgently. Put the frequency converter in the central control room. If the frequency converter is far away from the central control room, the current signal of Ma and some switching values can be used as control connections; If the distance is longer, RS485 serial communication can be used to connect; If you want to extend the distance, you can use the communication intermediate relay to reach a distance of 1km; If optical fiber connector is used, it can reach 23km away. Using communication cable connection, it is convenient to form a multi drive control system, so as to achieve the requirements of master/slave and 2 experimental machine level 0.5 synchronous control. Connecting with the current popular fieldbus system will greatly improve the data conversion rate. The extension of the distance between the central control room and the frequency converter cabinet is conducive to shortening the distance between the frequency converter and the oil pump motor, so as to improve the system performance with a more reasonable layout

in short, when installing the frequency converter, it is necessary to comprehensively consider the distance between the central control room, the frequency converter and the oil pump motor, so as to minimize the influence of harmonics and improve the stability of control. (end)