The Research And The Application Of The AC Frequency-convert Driver System Using On The Nip-web Paper Machine

This paper is a study and an analyse of the application of the AC frequency-convert driver system using on the nip-web paper machine. The technicology of the paper machine driver system has a very important site in the modern paper making industry. The conventional DC driver system is replacing by the AC frequency-convert driver system. It can completely meet the requirement of the multi-driver system of the paper machine, and it will also bring good influence to both society-effect and economy-effect, that applying advanced technicology of the driver system to the paper machine.This paper particularly introduces the main control theory of the AC frequency-convert driver system and the basic character of the nip-web paper machine dirver system. Because the AC asynchronous motor' synchronous speed is determined by the frequency, we can control the AC asynchronous motor' speed by changing the supply power's frequency.In modern paper mill, the machine runs continually, and 340 days per year. Only a little accident in the driver system can stop the machine, it may lost a lot of pulp and produce a lot of waste paper. Because it may take a lot of time to go back to the continually working status, this accident stopping machine may make a big loss to the factory. Base on this notion, people normally use AC frequency- convert driver system, which mostly should import. Although it has good quality and works stably, it cost so much and the maintenance is not convenient enough. As the project mentioned in this paper saved much investment by only importing the main organ and assembled it in local factory, And it can fulfilled the paper mill's requirement, there should be a very big market for this AC Driver System.This paper also explains how to limit the driver motor bearing's current in this project. After adopting the methods mentioned in this paper, we can use the bearing made in china to replace the expensive import one. As the driver system the the biggest source of the harmonious current in paper making factory, we should adopt multiform harmonious current restrained way to guarantee the whole system can work well. This paper also analyses some problem occured in the field-work.