Views: 0 Author: Site Editor Publish Time: 2022-09-16 Origin: Site
my country's paper industry has developed very rapidly in recent years. Similarly, the application of frequency converters in the transmission system of paper machines is becoming more and more common. This article introduces several commonly used frequency converter parameters and setting methods in papermaking transmission systems.
According to the requirements of the papermaking process, we already know some basic requirements of the paper machine for inverters. Now most general-purpose inverters can basically meet these conditions. However, if the parameters are set improperly, it will also affect the performance of the system, and even cannot operate normally. , for the general-purpose inverter, its main parameters and settings can be considered from the following aspects:
1. Operating frequency signal parameters
Setting the operating frequency of the inverter: The dedicated inverter can obtain the operating frequency from many of the following aspects.
(1) The actual operation control panel On the display control panel of the inverter, there will be buttons for increasing the operating frequency and decreasing the operating frequency, through which the operating frequency of the inverter can be changed. This is a digital setting of the operating frequency. Because this type of mode cannot actually change the operating frequency of the variable frequency governor on the spot, therefore, its application range is subject to corresponding restrictions, and it is only used in places where a single motor drives and does not often change the operating frequency. .
(2) Analog terminal general-purpose inverter
The analog terminals usually have two types of current and voltage input and current input. The current input usually has two types: 0~20mA and 4~20mA, which can be arbitrarily set in one or a variety of inputs. Convert it to a digital quantity with an A/D of about 10 bits. Using this form to set the operating frequency of the inverter can realize the actual operation of external control, and it can be changed in real time on the spot, but the analog quantity is easily affected during the transmission process, especially the current and voltage signals, which are more vulnerable. Influence, resulting in instability of the system operation, it is recommended to use the current signal, on the other hand, use the analog value to set the operating frequency, and also deal with the problem of speed synchronization in the automatic control system of the paper machine transmission system.
(3) Digital terminal
Such a method of setting the frequency, the variable frequency governors of various products have different opinions, such as ABB variable frequency governors are called electric potentiometers, and Fuji inverters are called raising/lowering basic functions, etc., in fact, they are It is said that the frequency converter's own multi-purpose digital input terminals are used to change the operating frequency of the frequency converter, and the rate of acceleration/deceleration can be adjusted. This method is more typical in the paper machine transmission system with an eight-cylinder paper machine. .
(4) Communication method
This kind of method to set the operating frequency of the inverter by serial communication is more common in the large-scale paper machine transmission system, such as RS-485 or CAN bus.